The University of Guelph’s Animal Health Laboratory recently published a summary of selected zoonotic disease diagnoses in its monthly newsletter. It’s an interesting summary of what’s gone through the lab in the last year. It also helps to remind us of the zoonotic potential of all of these pathogens, some of which are relatively common and can be found in a variety of species.
A female Corgi was presented to a Parker County, Texas veterinary clinic and subsequently diagnosed with rabies. Presumably, the dog was exhibiting neurological signs, died or was euthanized, and the veterinarian made sure the dog was tested for rabies (something that could become more complicated in Canada now that the CFIA has inexplicably dumped rabies investigation from their mandate).
Presumably, the dog contracted rabies from a skunk, since it brought a skunk carcass home with it a few weeks earlier, and that timeframe that fits with rabies' incubation period.
The dog's vaccination status wasn't reported, but it was probably not vaccinated against rabies. Rabies vaccination is not a 100% guarantee against contracting the disease (no vaccine is), but it's a very good vaccine, and failure of the owners to get the dog vaccinated is the most common contributing factor to rabies in dogs and cats. It's interesting that there were two other dogs in the family that were up-to-date, so it would be nice to get clarification of this dog's vaccination status.
Unfortunately, the dog was nursing a litter of five-week-old puppies at the time, and the puppies were euthanized. It's hard to say how likely it is that they had contracted rabies, but regardless, a six-month strict quarantine and hand-raising a litter of puppies don't exactly go hand-in-hand.
The report also says that two adults and a child are "currently under medical supervision and treatment as a precautionary measure," meaning they are getting a course of post-exposure prophylaxis, which consists of a shot of anti-rabies antibody and a series of four shots of rabies vaccine.
There's no guarantee, but effective vaccination might have prevented the death of the dog, euthanasia of five puppies, hassles with (presumably) a 45 day observation of the vaccinated dogs, and the angst and expense of post-exposure prophylaxis for three people. Rabies vaccination is well worth the investment!
I’ve written before about concerns I have with international rescue programs. We’ve been seeing various "foreign" diseases in dogs that have been imported to Ontario, and some of these could pose a risk to the broader dog population. I also have a hard time justifying someone spending a few thousand dollars to import a dog when we have lots of dogs right here in local shelters looking for homes. Often, people just want to be able to say they have an “[insert exotic sounding country here] rescue dog.”
There’s been a lot of discussion about stray dogs in Sochi, Russia, where there is a large stray population and reports of culls being undertaken by Russian authorities. Not surprisingly, even such a concerted effort isn’t going to get rid of all strays. More than a few people at the Sochi Olympics have bonded with local strays and are looking into bringing home a canine souvenir.
To me, this is a different situation than the one above, since these people have bonded with a specific dog (or dogs) and I can more easily justify the effort and cost to bring those dogs home.
However, disease risks remain the same.
Unfortunately, rules for importing dogs are very limited for most countries and don’t do much to protect the local dog population or public health. Typically, the only government concern is rabies, and even for that disease the rules are pretty lax.
- If it’s been vaccinated against rabies at least 30 days prior to entry, that’s all that's needed.
- If it has not been vaccinated, it can still be imported if the importer agrees to vaccinate the dog within 4 days of arrival and keep the animal confined for at least 30 days after vaccination.
- If the dog is less than 3 months of age (too young for rabies vaccination), it must be kept confined until 3 months of age, at which point it needs to be vaccinated and confined for 30 more days.
(I doubt anyone actually follows up to see if vaccination or confinement are done.)
Importing a dog into Canada
- This one’s even easier. If the dog is less than 3 months of age, it’s "welcome to Canada," since “Dogs do not require rabies vaccination or certification if they are less than three months of age at the time they are imported into Canada.”
- There is no quarantine or follow up.
So if you’re coming back from Sochi with a puppy, you’re not going to get a lot (or any) guidance from federal authorities. What should you do to protect the puppy, other animals and yourself?
- Take the dog to a veterinarian ASAP to identify any problems, and have it dewormed and vaccinated. Make sure it gets treated right away with praziquantel to eliminate any Echinococcus multilocularis (a highly concerning tapeworm) that might be present. (I have no idea what the prevalence of this parasite is in the Sochi area, but I’d err on the side of caution and assume the dog’s infected, particularly since a single dose of this very safe and inexpensive drug will eliminate it.)
- Keep the dog away from other dogs for at least a few weeks. That means staying away from parks and other areas where it may encounter local dogs. This helps to protect the other dogs AND the new arrival, since it takes time for vaccines to work and there may be some impact on the immune system from the stress of travel and adjusting to a new home.
- If the dog gets sick, get it to a veterinarian. Don't mess around.
- If the dog develops neurological disease, make sure rabies is considered. The incubation period can be months, and while we need to think about rabies in all neurological cases, it’s of particular concern in dogs imported from some other areas of the world.
If someone bonds with a dog while and Sochi and wants to bring it home, good for them. However, they should take some measures to reduce the health risks to their new furry friend, other animals and themselves.
Antibiotic resistance is a big deal. Lots of people and animals die because of it every year. It costs the healthcare systems (human and veterinary) tremendous amounts of money and it’s not getting better.
It’s been clear for years that we have to do a better job of using antibiotics responsibly, in both animals and humans. It’s a complex area, and people often spend too much time complaining about the "other" side (human vs veterinary) rather than trying to address their own problems. However, there are issues with certain practices that seem so straightforward I’m amazed they're allowed to continue and that they haven't already been addressed.
One such issue is the ability to buy certain antibiotics in large volumes over the counter at feed stores in some countries (like Canada), with no veterinary involvement.
Another is the plethora of fish antibiotics you can buy all too easily in pet stores (and which often end up being used on dogs and cats).
And today’s rant is about a group of products that's ongoing use boggles my mind: tear stain prevention products like Angels' Eyes. These are over-the-counter products marketed to reduce tear staining, mostly in small, white dogs. Yes, tear staining - an entirely cosmetic problem that has absolutely no impact on health. The scary part is that products like Angels' Eyes contain tylosin, an antibiotic of the macrolide family. (How much it contains is a bit of a mystery since that information isn't even included on the label.)
Does it make any sense to treat animals for a purely cosmetic problem for long periods of time (or lifelong) with a (presumably) low dose of any antibiotic, let alone one in a drug class that includes many antibiotics that are important for treating infections in people and animals?
In some countries, irrational antibiotic use like this is banned. More countries need to follow suit.
The American Heartworm Society (AHS) recently issued a release emphasizing that "Contrary to what owners may think, heartworm disease is a year-round threat" and encouraging people to use heartworm preventive medications year round.
I’m in Canada, not the US, but some US regions have a similar climate and similar issues to us. Also, some people try to directly apply US recommendations to Canada, so I’ve critiqued their reasoning below, from an Ontario context.
The AHS based the release on 3 "facts":
Fact #1: Pesky pests pay no attention to the calendar.
- Mosquitos and heartworm don’t pay attention to the calendar, but they do pay attention to the weather. The picture to the right is the view of our deck (prior to the last couple rounds of snow). I don’t think there are many mosquitoes hanging around out there. Yes, they are somewhere, since they don’t become extinct over the winter, but is mosquito exposure a reasonable concern now? No.
- Furthermore, development of Dirofilaria immitis (the heartworm parasite) in mosquitoes ceases at temperatures below 57F, a level we haven’t seen in a while (and likely won’t for a couple of more months). So, even if there are mosquitoes hanging around at the beginning and end of the "heartworm season" in temperate areas, if the parasite can’t develop, it doesn’t matter much.
Fact #2: Mosquitoes know when to come in from the cold. When weather changes prompt pets to spend more time inside, mosquitoes follow, keeping the possibility of heartworm transmission alive. This means that so-called “indoor” pets are as much at risk as their more outdoorsy counterparts.
- I’d like to see some data backing that up. I haven’t had a mosquito bite in a while.
Fact #3: Staying on schedule with heartworm prevention keeps pets safe.
- Potentially, but assuming every pet owner is forgetful and unable to figure out how to treat their animal once a month over a prescribed part of the year isn’t really a reasonable justification for a treatment regimen that uses more drug and costs more money.
- There is no evidence that 12-months-a-year treatment results in any better compliance than targeted seasonal treatment. (If I can’t remember to give it 6 months of the year, does adding 6 more months really help?)
- Around here, the vast majority of heartworm cases are in dogs that are not on heartworm prevention medications, not in dogs in which treatment failed, potentially because of compliance problems. Is it possible that some people would be more reliable with monthly treatment? Sure. It’s also possible that some people would be as bad (or worse) with year round treatment. It’s also possible that some dogs would go untreated altogether if their owners balked at the cost of year-round treatment.
The bottom line for me:
Heartworm’s a nasty disease and one that we need to prevent.
There are effective preventive medications.
Ontario isn’t Louisiana. In some areas of North America, year round treatment is absolutely needed. In others, the risk period is much shorter.
Decisions about the approach to prevention need to be based on the risk in the area, the duration of likely mosquito exposure, the outdoor temperature and the owner’s ability to comply with treatment. This is a discussion that needs to take place between pet owner and veterinarian on an individual basis.
There is no one-size-fits-all approach to heartworm prevention.
Merlin and I will each get hundreds of mosquito bites this year (surrounded by wetland as we are). He'll get his monthly heartworm prophylaxis during what I feel to be the "at-risk" time of year. That doesn't include today, when it was -21C this morning!
For the third time in the past year, Macon-Bill Animal Welfare in Georgia (USA) has a problem with canine parvovirus. The shelter is closed for two weeks in response to a puppy testing positive for this highly contagious virus that can cause serious disease in dogs (almost exclusively in unvaccinated puppies). At first glance, it may seem like an overly-aggressive response. A single parvo case isn’t too surprising in a shelter, and if appropriate routine precautions are followed, there are sound protocols to isolate parvo suspects and a good vaccination program, the risk to other animals can be contained.
In this outbreak, 14 puppies have been euthanized (though some reports differ). Again, the news reports are pretty crappy and it’s unclear whether all the puppies were sick or whether they were euthanized because they were exposed. The statement that parvovirus infection is "most times fatal for dogs" is wrong, since it’s usually treatable, but it certainly takes time, effort and money - things that may be of limited availability in a shelter. Also, if the shelter has inadequate facilities or personnel to properly treat and contain parvo, euthanasia gets considered more readily that in better equipped facilities.
The first report also says that the shelter refunded adoption fees of people who adopted puppies that subsequently died from parvo, so it does sound like there was probably a real (and possibly large) outbreak.
Closing a shelter is an extreme move but it’s sometimes required. It helps reduce the number of animals in the facility in order to make isolation of sick animals, separation of groups, management of exposed and infected animals and many other aspects of the infection control response easier. It also stops adding fuel to the fire, by halting admission of new susceptible animals that can get sick and thereby propagate the outbreak.
Some shelter outbreaks are the result of poor routine management (and some incompetence). Some are the result of inadequate response to an infectious animal. Some are an over-reaction to a limited and containable problem. Some will occur despite the best practices in the best facility. That’s the nature of infectious diseases. Any time there’s an outbreak, a shelter needs to figure out which of the above categories they fit in so that they can reduce the risk of future problems.
(For tracking of selected infectious diseases and outbreaks, stay tuned for the launch of WormsAndGermsMap. More information to come!)
A recent high profile dog-bite death in the US has refocused discussion on bites and their causes. Co-incidentally, a paper in a recent edition of the Journal of the American Veterinary Medical Association (Patronek et al 2013, Co-occurrence of potentially preventable factors in 256 dog bite-related fatalities in the United States (2000-2009)) also addresses this topic.
The authors of the study looked at 256 dog bite fatalities and, primarily using investigation reports from law enforcement agencies, looked at potential preventable factors. This was a pretty intensive effort compared to other studies, involving review of all available documentation and interviews with investigators and animal control officers whenever possible.
Here is a synopsis of some of their interesting results:
- The overall dog bite fatality rate was approximately 0.087 fatal bites per million person years (or 8.7 fatal bites per 100 million people per year) and 0.38 fatal bites per million dogs. That’s low, but that's small comfort if you’re one of the 0.087.
- Almost half of the victims were less than 5 years of age, with slightly more males than females.
- Few victims (6.6%) were the dogs’ owners, and owners were present at the time of the bite in only 4.7% of cases. In 74% of cases, there was no relationship to the dog (i.e. the animal was not owned by the victim, a friend or relative, or some other situation in which the person knew the dog).
- In slightly over half of the cases, the victim was deemed "unable to interact appropriately," mainly due to young age. In another 22%, the victim was deemed "possibly" unable to interact appropriately, due to being 5-12 years of age, or having cognitive impairment because of age, mental disability, intoxication or seizures.
- 87% of the time, there was no able-bodied adult present who could have intervened.
- 58% of the time, only a single dog was involved. However, 87% of infant deaths were from a single dog.
- 74% of bites occurred on the owner’s property.
Obviously, dog factors get a lot of attention when it comes to fatal attacks. Here are a few:
- Most dogs were 23-45 kg.
- 88% were male.
- 84% of dogs were not spayed or neutered.
- 38% of the time, the owner or caretaker was aware of prior dangerous behaviour by the dog, or had repeatedly allowed the dog to roam freely.
- In 21% of cases, there was evidence that the dog had been neglected or abused.
- Breed reporting, which is important because it’s such a high profile subject, was pretty poor. Media often reported different breed info, and media and animal control reports often differed.
Dog bites cannot be eliminated entirely but they certainly can be reduced. A variety of approaches are needed, including measures directed at dogs, dog owners, the public and authorities. Understanding potentially preventable or modifiable factors (e.g. neutering, supervision, addressing previous aggressive behaviour) is an important step to developing optimal preventive approaches.
As we were heading into our 5th day without power as a result of a nasty ice storm, the power came back on. It’s been a pain, but with the generator, fireplace and family to visit in unaffected areas, it’s more disruptive than anything.
Not everyone’s that lucky.
If you don’t have a generator or someone with power with whom to stay, what do you do (especially when the temperature dipped to -18C last night)?
Also, what do you do if you have pets?
You might be able to find someone with power to take them or you might find a kennel (if there is one with power and space, and if you can afford it). If not, what then? Warming centres have been opened up, but what would happen if we showed up at one with two dogs, two rabbits and a cat? (The sheep would have to get by on hay and snow, and the fish... well... they’d be screwed.) I doubt our menagerie would be welcomed.
So, you’re left with deciding whether to leave the animals at home with a big pile of food and hoping for the best, or staying behind with them.
It is a serious issue, and I can virtually guarantee there are people toughing it out in freezing houses because they didn’t have any place to put their pets.
When large-scale natural disasters occur, animal care can be an even bigger issue. I heard a figure once about the number of people who died in Hurricane Katrina, having refused to evacuate as it approached because their pets couldn’t be evacuated with them. I’m hesitant to repeat the number since I haven’t been able to find it in a well-documented source, but even if it’s a gross over-estimate, it’s still huge.
It’s also relevant on a smaller scale, on many fronts, such as homeless people staying out of shelters because they can’t take their pets (commonly dogs) with them.
Making plans for management of pets is important for situations such as these. Some people dismiss it as “why would you want me to waste time, energy and money saving a few dogs and cats when people are at risk”? Those individuals are missing the point. The goal isn’t to save the dogs and cats (though that’s a nice side-effect) - it’s to remove barriers to assistance that may be in place when people are unwilling to leave their animals behind. It’s not simple, since you have to consider a lot of things like feeding and housing animals, keeping them controlled, making sure there are no problems with bites or people who are fearful or allergic to animals, and taking precautions to prevent zoonotic diseases.
It’s not easy and it needs to be planned in advance - not during a crisis - but it’s something that needs to be done.
I write about Capnocytophaga canimorsus regularly... disproportionately so, since it’s a rare cause of disease in people. However, though rare, when disease does happen it’s usually serious, and cases illustrate some important basic concepts that apply more broadly to other zoonotic diseases from pets.
The title of this post is from the latest edition of the Canadian Journal of Infectious Diseases and Medical Microbiology, which includes a report describing a single case of Capnocytophaga infection in a person (Popiel et al 2013). In that respect, it’s not particularly remarkable, but some common themes and a few interesting statements that appear are worth considering.
The case report is about a 56-year-old male who presented with fever, headache, joint pain and nausea. He had some other health problems and was a heavy drinker (a major risk factor for Capnocytophaga infection). He developed Capnocytophaga meningitis and deteriorated quickly, but fortunately responded to treatment. The family dog had bitten the man on a finger a week earlier. As is common, it was a minor bite and one that was likely dismissed as inconsequential. However, a minor bite is all that’s needed to drive Capnocytophaga into the body.
The paper starts with the sentence “In 1976, Bobo and Newton (1) described a syndrome that would forever change mankind’s relationships with their canines.”
I think that’s completely false. I’d wager that >99.99% of people have never heard of this bacterium. Most veterinarians haven’t either, and I suspect the same could be said about most physicians. So, I don’t see how it could have had a major impact on how people interact with dogs.
In some ways, I’d like this statement to be true, if it meant that people paid more attention to zoonotic diseases and improved basic disease prevention practices (e.g. hand hygiene, having high risk individuals avoid contact with saliva, good bite prevention and bite care). In other ways, I’m glad it’s not true, were it to result in people being paranoid of this bacterium (that’s found in the mouth of pretty much every dog) and limiting the positive aspects of pet ownership and contact.
More information about Capnocytophaga can be found on the Worms & Germs Resources - Pets page.
It’s flu season so I’ll take advantage of the time to talk about flu of a different type… canine flu.
Canine flu is different from seasonal flu in people. It’s caused by canine influenza A H3N8, and has spread around the US is a rather meandering and unpredictable manner. It’s caused major problems in dogs in some areas, while other areas have been completely unscathed.
Influenza in animals is a concern for animal health, but there are also human health concerns because of the ability of many influenza viruses to cross species barriers.
The human health risk posed by canine flu has been unclear, but it’s been assumed to be low. One reason is that there have been no credible reports of disease in people working with infected dogs (although that’s a far-from-convincing degree of evidence). More importantly, from my standpoint, is that canine influenza originated from, and is still closely related to, equine influenza H3N8. This virus is widespread in horses internationally (and has been for a long time) and it’s not of much zoonotic concern.
However, it’s always good to have more information, and a recently published study (Krueger et al, Influenza and Other Respiratory Viruses 2013) explored this area further. The researchers looked at 304 people who were regularly exposed to dogs and 101 people who did not have canine exposure, and they looked for antibodies against H3N8 influenza in the subjects’ blood.
There were no differences in antibody levels between the two groups, suggesting no evidence of flu transmission from dogs to people.
The study would be more informative if they knew whether any of the people had been exposed to dogs with influenza (or respiratory disease, in general), so conclusions from the study are somewhat limited. The study targeted people at higher risk for exposure to dogs with flu, such as show dog owners, racing greyhound caretakers and similar groups, which is good. More useful would be a study looking at owners or caretakers of dogs with canine flu and comparing them to other dog owners and people with no dog contact (although that’s not easy to do).
So, we’re still left with some questions but no convincing evidence that canine flu is a human health risk. That being said, it would be better not to have it circulating in the dog population where a co-infection of an animal (or person) with H3N8 and a common human flu virus could result in a new virus that is more easily able to infect people and to which there’s little resistance in the human population. New flu viruses are potentially a big problem, as the bird/pig/human pandemic H1N1 flu virus showed a few years ago.
A little knowledge can be a bad thing. We see that with zoonotic diseases. Awareness is great. However, a little bit of awareness can be a problem if it’s enough make people paranoid but not enough to help them understand the real risks. This can lead to excessive and illogical responses (often ending with "...get rid of the cat").
Sound guidelines for preventing infections written by authoritative groups help a lot. An example of that is the recently updated Guidelines for the prevention and treatment of opportunistic infections in HIV-infected adults and adolescents. As a collaborative set of guidelines from the US Centers for Disease Control and Prevention (CDC), the National Institutes of Health, and the HIV Medicine Association of the Infectious Diseases Society of America, it carries a lot of weight - as it should.
It’s a monster of a document of 416 pages. Pet contact gets a little bit of room and probably just the right amount. Enough to say "it’s something to think about," "we’ve considered the issues" and "here are some basic things to consider.”
Here are their specific recommendations:
Hand-washing also should be recommended in association with the following activities: after handling pets or other animals, gardening or having other contact with soil; before preparing food or eating; and before and after sex (BIII).
HIV-infected individuals—particularly those with CD4 counts <200 cells/μL [i.e. people who have advanced disease]—should avoid direct contact with diarrhea or stool from pets (BIII).
Gloves should be worn when handling feces or cleaning areas that might have been contaminated by feces from pets (BIII).
HIV-infected individuals also should avoid other sources of Cryptosporidium oocysts as much as possible (BIII). These include working directly with people with diarrhea; with farm animals such as cattle and sheep; and with domestic pets that are very young or have diarrhea. If exposure is unavoidable, gloves should be used and practices for good hand hygiene observed.
The letters and numbers indicate the strength of evidence. B means there’s moderate evidence supporting the recommendation and III means it’s based mainly or exclusively on expert opinion, not research trials.
Note that nowhere does it say "get rid of the pet" or "avoid contact with animals altogether." Rather, it endorses the use of basic hygiene practices and common sense. In reality, all these recommendations could apply to any individual, not just people with HIV infection.
The preamble to the pet section includes a great statement:
Health-care providers should advise HIV-infected persons of the potential risk posed by pet ownership. However, they should be sensitive to the psychological benefits of pet ownership and should not routinely advise HIV-infected persons to part with their pets. Specifically, providers should advise HIV-infected patients of the following precautions.
…and those precautions are:
HIV-infected persons should avoid direct contact with stool from pets or stray animals. Veterinary care should be sought when a pet develops diarrheal illness. If possible, HIV-infected persons should avoid contact with animals that have diarrhea.
When obtaining a new pet, HIV-infected patients should avoid animals aged <6 months (or <1 year for cats) and specifically animals with diarrhea. Because the hygienic and sanitary conditions in pet-breeding facilities, pet stores, and animal shelters vary, patients should be cautious when obtaining pets from these sources. Stray animals should also be avoided, and specifically those with diarrhea.
Gloves should always be worn when handling feces or cleaning areas that might have been contaminated by feces from pets. Patients should wash their hands after handling pets and also before eating. Patients, especially those with CD4 cell counts < 200 cells/μL should avoid direct contact with all animal feces to reduce the risk for toxoplasmosis, cryptosporidiosis, salmonellosis, campylobacteriosis, E. coli infection, and other infectious illnesses. HIV-infected persons should limit or avoid direct exposure to calves and lambs (e.g., farms, petting zoos). Paying attention to hand hygiene (i.e., washing hands with soap and water, or alcohol-based hand sanitizers if soap and water are unavailable) and avoiding direct contact with stool are important when visiting premises where these animals are housed or exhibited.
Patients should not allow pets, particularly cats, to lick patients’ open cuts or wounds and should take care to avoid any animal bites. Patients should wash all animal bites, animal scratches, or wounds licked by animals promptly with soap and water and seek medical attention. A course of antimicrobial therapy might be recommended if the wounds are moderate or severe, demonstrate crush injury and edema, involve the bones of a joint, involve a puncture of the skin near a joint, or involve a puncture of a joint directly.
Patients should be aware that cat ownership may under some circumstances increase their risk for toxoplasmosis and Bartonella infection, and enteric infections [although I’d argue data supporting a broad statement of cat ownership increasing those risks that are largely lacking]. Patients who elect to obtain a cat should adopt or purchase an animal aged >1 year and in good health to reduce the risk for cryptosporidiosis, Bartonella infection, salmonellosis, campylobacteriosis, and E. coli infection.
Litter boxes should be cleaned daily, preferably by an HIV-negative, non-pregnant person; if HIV-infected patients perform this task, they should wear gloves and wash their hands thoroughly afterward to reduce the risk for toxoplasmosis. To further reduce the risk for toxoplasmosis, HIV-infected patients should keep cats indoors, not allow them to hunt, and not feed them raw or undercooked meat. Although declawing is not usually advised, patients should avoid activities that might result in cat scratches or bites to reduce the risk for Bartonella infection. Patients should also wash sites of cat scratches or bites promptly and should not allow cats to lick patients’ open cuts or wounds. Care of cats should include flea control to reduce the risk for Bartonella infection. Testing cats for toxoplasmosis or Bartonella infection is not recommended, as such tests cannot accurately identify animals that pose a current risk for human infection.
Screening healthy birds for Cryptococcus neoformans, Mycobacterium avium, or Histoplasma capsulatum is not recommended.
HIV-infected persons should avoid or limit contact with reptiles (e.g., snakes, lizards, iguanas, and turtles) and chicks and ducklings because of the high risk for exposure to Salmonella spp. Gloves should be used during aquarium cleaning to reduce the risk for infection with Mycobacterium marinum. Contact with exotic pets (e.g., nonhuman primates) should be avoided.
I'm getting ready for next week's ASM/ESCMID conference on methicillin-resistant staphylococci in animals, for which I'm involved in a plenary session about critically important antibiotics in companion animals. The whole area of antibiotics and animals in complex and controversial (and made worse by political agendas, lack of evidence and confusion about different issues).
Anyway, one thing that often gets overlooked is the difference between companion animals and food animals in how antibiotics are used, what regulations are in place, and what differences should be present between species. Just discussing antibiotics "in animals" isn't adequate, because a pet dog is very different from a feedlot steer in many respects, and many of the issues around antimicrobial use are different as well.
One question that's going to be up for debate is "should antibiotics that are used in serious resistant infections in people be used in animals?"
My answer to this important question has evolved a bit over the years. It's "yes, but..."
The but is the important part.
- As a veterinary clinician, I see the need to treat my patients (or the patients I'm providing advice on).
- As someone who works in the field of antimicrobial resistance, I see the issues with drug use and resistance.
- As a parent, I don't want my kids to develop a serious infection that I may have played a role in fostering.
- As a pet owner, I understand the desire to try to save the life of a pet.
That doesn't even cover all the issues, but it shows the variety of standpoints that need to be considered.
Back to the question at hand. As I said, my answer is yes, but with disclaimers:
- We need to use antimicrobials only when required.
- We need to use antimicrobials properly.
- We need to take measures to reduce infections overall (so that less antimicrobial use is required).
At our veterinary teaching hospital, we have a restriction policy for vancomycin, an important human drug. For it to be used in an animal, the following criteria must be met:
- The offending bacterium must be susceptible to vancomycin (duh!).
- There must be no other reasonable antibiotic options that are likely to work.
- There must be a reasonable chance of survival with treatment.
- Systemic treatment of the infection is needed (i.e. it can't just be treated with local therapy).
- The clinician must get approval from infection control (i.e. me).
That has happened twice in the past 12 years. Both cases were dogs with life-threatening abdominal infections; they were each treated with a short course of vancomycin and survived.
That's probably 10-14 days of vancomycin use per ~200 000 patients. I don't know what the comparable numbers would be for people in Guelph General Hospital down the road, but their use would be staggering compared to ours. Also, the risk of resistance with each use is presumably much higher for each human patient since they are in an environment where vancomycin resistant bugs are present (and therefore can be selected for with treatment). Vancomycin resistance is exceedingly rare in our hospital population, further decreasing the risk.
Is there some risk? Certainly. Use inevitably carries some risk.
Does our 2 / 200 000 use constitute a reasonable human health risk? I can't see how it does.
So, is antibiotic use in animals something we can just ignore? Absolutely not. It's a big problem, just like antibiotic use in people. However, just as all animal species issues aren't the same, all types of antibiotic use aren't the same.
Are there other things we can focus on to reduce resistance? Absolutely.
- A 1% improvement (i.e. decrease) in use of fluoroquinolones in animals would probably have a dramatically greater effect on resistance in human and animal pathogens than a complete ban on vancomycin. Fluoroquuinolones are a commonly used drug class in animals that is also important in people, and one in which resistance is certainly an issue.
- A 1% improvement (i.e. decrease) in use of of fluoroquinolones in humans would probably have an even greater effect.
- Better infection control, preventive medicine and other practices could potentially have an even greater impact by reducing infections and therefore the need for any drug therapy, and delaying the treat-resistance-more treatment-more resistance cascade.
Some people would say that any drug that's of any relevance in humans should not be used in animals. Some veterinarians would say no one should control their prescribing practices. Like most things, I think there's a happy (and more effective and practical) middle ground. It's not the status quo, though. We need to have discussions about how to control antimicrobial use in all species, including humans, and not just pointing fingers at the other side. We also need to discuss how to improve infection control to reduce the need for antimicrobials, and how to improve the way we use antimicrobials when they are required. In order to have good discussions, we also need proper data (something that's still lacking).
Different opinion? Feel free to comment (or show up in Copenhagen next week).
A few days ago, I received a question about whether bathing a young child and a dog together in the bathtub is a bad idea.
It’s not really something I had considered before because, despite having 3 kids and 2 dogs, it’s never crossed my mind to toss them in the tub together. Anyway, I guess it’s a reasonable question since apparently some people are doing it. So, here’s my thought proces:
Is there a risk?
Sure. We know there’s always some risk of disease transmission when interacting with an animal. Generally, the risk is quite low and therefore the pet contact is still worth it because of all the other positive aspects, but in some situations, the risk goes up. We know that risks are higher with young children, and that bacteria present in the intestinal tract of dogs are probably the most common issue.
Is the risk a realistic concern?
Yes I think so. When a dog is bathed, presumably there’s going to be some contamination of the water with fecal-origin bacteria from the animal’s rear end and/or haircoat. There’s also a pretty good chance that contaminated water would be ingested by the child, considering how often toddlers put bath toys in their mouths or drink the water.
What’s the benefit?
Of bathing a child and dog together? None that I can think of.
Is it an avoidable risk?
This one’s easy. Yes. Don’t bathe pets and children together. That’s the best way to avoid the risk and seems like a common sense recommendation to me.
It's that time of year again… time for the US annual rabies surveillance report in the Journal of the American Veterinary Medical Association (Dyer et al 2013).
- There were 6162 cases of rabies diagnosed in animals in 2012. (This is a 2.1% increase from 2011, but I don't put much stock into changes like that when the tested cases only represent a minority of the animals with rabies.)
- The vast majority (92%) of rabid animals were wildlife, with raccoons "winning" at 32% of all animals diagnosed. They were followed by bats (27%), skunks (25%), foxes (5.5%), cats (4.2%), cattle (1.9%) and dogs (1.4%)
- A variety of other animal species were also diagnosed as rabid, including bison, llamas, bobcats, deer, a cougar, a mink, groundhogs, opossums and beavers. That just shows how any mammal is at risk. I was surprised at the number of rabid groundhogs (42 in 10 states).
- While dogs accounted for only 1.4% of cases (84 animals), a disproportionate number were found in Puerto Rico (18), with relatively large numbers also in Texas (16), North Carolina (9), Georgia (7) and Oklahoma (7). Presumably this relates to a combination of lower vaccination rates and a higher level of endemic rabies in the wildlife population in these areas. It appears that none of the rabid dogs were properly vaccinated against rabies, although vaccination history was not known for many.
- Rabid cats were mainly found in areas where raccoon rabies was common. Pennsylvania had the most rabid cats (15.6%). Other commonly affected areas were Virginia, North Carolina, New Jersey and Georgia.
- The distribution of rabies virus types was pretty much as expected. Raccoon rabies virus predominated on the east coast. Skunk rabies covered the central US, overlapping with fox rabies in the southern regions. Fox rabies was also dominant in the Nevada and Arizona area, while skunk rabies predominated in central to northern California. Fox rabies dominated in Alaska and the mongoose rabies virus strain was found in (not surprisingly) Puerto Rico.
Some Canadian data were also reported:
- There were 142 confirmed rabies cases in animals, 84% of which were wildlife.
- There were 18 rabid cats and dogs, 4 livestock and one person. The person was infected with rabies while abroad, in Haiti.
- No rabid raccoons were found - something that has been the case since 2008.
And in Mexico…
- There were 12 cases of rabies in dogs, and those involved the canine rabies virus variant which is not present in Canada or the US.
Take home messages:
- Rabies... still here (and not going away any time soon).
- Vaccinate your animals.
- Stay away from wildlife.
Image: Distribution of major rabies virus variants among mesocarnivore reservoirs in the United States and Puerto Rico, 2008 to 2012. (click for source: Dyer et al. J Am Vet Med Assoc 2013)
I’m not a big fan of the title of a paper in the latest edition of the Canadian Journal of Infectious Diseases and Medical Microbiology…”Pets are ‘risky business’ for patients undergoing continuous ambulatory peritoneal dialysis” (Yahya et al 2013), even though it’s an interesting paper that actually takes a reasonable approach to zoonotic disease risk from pets. I get a little concerned with titles like this that might reinforce certain excessive fears that some physicians have (usually from lack of understanding) regarding pets and zoonoses.
The paper is a case report of a 49-year-old man with kidney failure who was undergoing peritoneal dialysis at home. Peritoneal dialysis involves infusing fluid into the abdomen and then draining it, to help flush toxins out of the body. This requires an indwelling abdominal catheter that is placed through a small hole in the body wall. Any time a tube gets stuck into the body, there’s some risk of it acting as a pathway for infectious organisms to also get in. Good management practices are essential to reduce the risk of infection in these cases, but good practices are not always used.
In this case, the person had a dog and a cat in the household. Over the course of about eight months, the man developed four different infections. One was caused by Pasteurella multocida, a bacterium that is very common in the mouths of cats. Another was caused by Enterobacter cloacae, a bacterium that is found in the intestinal tract of a variety of species, so it may or may not have been a pet-associated infection. The last two were both Capnocytophaga infections. This bacterium is ubiquitous in the mouths of dogs, and to a lesser extent cats.
How did these bacteria cause the infections?
The patient was adamant that the pets didn’t have contact with the dialysis tubing and that they were not present when he performed dialysis. However, he admitted that his hand hygiene practices weren’t always great, so presumably he contaminated his dialysis tubing with bacteria on his hands that came from the pets (either directly or from contaminated household surfaces).
Did the infections really come from the pets?
There was no testing of the pets to confirm it, but Pasteurella multocida and Capnocytophaga canimorsus are clearly pet-associated bugs, so I don’t have much doubt that pets were the source.
So, are pets risky in situations like this?
Yes, but so are lots of things. The key is whether we can effectively manage the risk.
Does the presence of pets in the house increase the risk of a person undergoing peritoneal dialysis getting an infection?
We don’t know. I’m not aware of anyone looking at this specifically. However, since people are still able to publish single case reports of pet-associated infections, it’s fair to assume that pet-associated infections in these patients are relatively rare (and therefore make interesting case reports).
Should people undergoing peritoneal dialysis at home get rid of their pets?
I can’t support that (unless no onein the household really has any affection for the pet, in which case why not eliminate the risk by finding it a new home). Infections seem to be rare and basic practices (especially good hand hygiene) can presumably reduce the risk even further.
The authors conclude with some nice, balanced recommendations. “Our data support the recommendations by Rondon-Berrios and Trevejo-Nunez (2), Weiss and Panesar (12), Pers et al (10), Schiller et al (6) and Sol et al (3) that PD patients who own pets be made aware of the need for proper hand hygiene before PD bag changes and the risk of zoonotic infection if these precautions are not taken. The need to ensure pet oral secretions do not come into contact with PD equipment and the threat of these infections should be clearly communicated to PD patients. We recommend strict hygiene guidelines be emphasized and periodically reviewed with PD patients who have pets.”
I’ve been holding off on writing about this one for a while since it’s been unclear what’s happening, but a strange disease situation appears to be ongoing in Ohio dogs.
There’s old adage in medicine: an uncommon presentation of a common disease is much more likely than presentation of an uncommon (or new) disease.
- aka common things happen commonly.
While this is certainly true, emerging diseases continue to just that. This one seems like it really is something new, and something to which we need to pay attention.
Reports have been coming in for a few weeks about severe and sometimes fatal gastrointestinal disease (e.g. vomiting and diarrhea), and deaths were occurring, particularly in dogs that were not treated early in disease. The usual suspects were ruled out, and eventually there was suspicion that the cause might be a circovirus.
Until recently, circovirus was only known to be a problem in pigs (where it’s a very big problem). Then, in 2012, a canine circovirus was reported in dogs in California with severe gastrointestinal disease, as well as some healthy dogs. Circovirus wasn’t proven to be the cause of illness, but it was quite suspicious that this could be a canine pathogen.
Because of the similarity in disease signs in the Ohio dogs and the ones from California, circovirus testing was done and apparently the virus has been detected.
This doesn’t mean that the virus is what's making the dogs sick. Since the virus can also be found in some healthy dogs, its role in disease is unclear. Certainly, it’s not a virus that causes disease in every dog that is exposed. So, at this point, we’re still a bit (or more than a bit) in the dark. Yet, there’s enough evidence to indicate that we need to investigate this virus, see where it is, where it’s going and figure out how to control it.
How can you protect your dog?
It’s not really clear, but basic infection control practices are probably the key at this point in time. The virus is spread through contact with feces of infected dogs.
- If your dog is sick, keep it away from other dogs and places where other dogs go (e.g. the dog park).
- If your dog is sick, take it to the vet. (Make sure they know why you’re coming in so that they can take appropriate precautions to isolate your dog, rather than having you hang out in the waiting room with other dogs while waiting to see the vet.)
- Keep your dog away from sick dogs.
- Pick up your dog’s feces. Always. Even if it’s healthy.
Nothing fancy or really anything beyond what people should normally be doing, but this situation is a good reminder of why we should use basic infection control practices routinely.
I haven’t heard of any concerns about this disease in Canada, but rapid investigation and communication are important, so any concerns about possible cases will hopefully be sent my way.
This is an increasingly common question, as methicillin-resistant Staphylococcus pseudintermedius (MRSP - essentially the canine version of the high-profile human "superbug" MRSA) has expanded greatly in the canine population. As more dogs get MRSP infections and even more become inapparent carriers of this bug, more dogs that are carriers will need surgery (both elective and non-elective). Since MRSP is now a leading cause of surgical site infections in dogs, there's concern about what to do with these carriers, particularly when it comes to elective surgeries like spays and neuters.
My answer to the question is... maybe.
If the dog has an active MRSP infection (e.g. skin infection), I'd say "hold off for a while" if possible. I don't like elective surgeries being done on animals with active infections (this applies to almost any kind of infection, not just MRSP). If an animal has an active MRSP infection, it might increase the risk of the surgical site becoming infected because of the greater overall burden of MRSP on the skin and elsewhere.
If the dog doesn't have an active infection (e.g. is a healthy carrier after having gotten over a previous MRSP infection), I'd say "go ahead."
- Spay-associated infections are quite rare.
- We don't use antibiotics prophylactically (i.e preventatively) for spays (or at least, they shouldn't be used for this kind of low-risk procedure - unfortunately some people still use them inappropriately).
- MRSP is no more likely to cause a spay infection than methicillin-susceptible S. pseudintermedius. It's just harder to kill when an infection occurs.
- Methicillin-susceptible S. pseudintermedius can be found on almost all dogs.
So, if infections are rare, despite the fact that S. pseudintermedius is present on pretty much all dogs and that we don't use drugs to kill S. pseudintermedius during (or after) spays, there should be no added risk of infection by the antibiotic-resistant version of this bug.
Every dog is carrying lots of different bacteria that can cause an infection at any time. That's why we use a variety of surgical antisepsis practices (e.g. clipping, scrubbing, sterile instruments, proper operating room) to help prevent a critical number of bacteria from getting into the sterile surgical site where they can start to cause problems.
This strategy doesn't necessarily apply to surgeries where antibiotics are used prophylactically and where staph are the main causes of infection, especially in situations like orthopedic procedures where MRSP infections are common and can be very hard to treat. What to do in those cases with an MRSP-positive animal is a tougher question, and we're working on an answer to it at the moment.
This one's not very surprising since it's the typical fake service dog scam, but it made me laugh. While on a completely unrelated website, I saw an ad on the page that said something like "Trouble walking on the beach with your service dog? Check us out." Unfortunately, I did.
The website sells the typical "service dog" paraphernalia - at a pretty high price. To start off, the site takes you through a series of questions.
1) Do you currently have a physical impairment?
2) Do you currently have a mental impairment?
- No (although my kids might have a different opinion on that one).
3) Do you have a record of a physical impairment or mental illness in the past that substantially limits one or more of your major life activities?
4) Are you regarded as having a physical impairment of mental impairment in the past that substantially limits one or more of your major life activities?
- "No, you probably do not quality"
So far, so good. That's the right answer.
But... (I love the rest...)
"However, this is a self-assessment and reasonable minds can come to different conclusions. You may wish to take our Disability Self-Assessment Test again. Alternatively, you may wish to visit our Products page and see whether it nonetheless may be helpful to you."
In other words, try again and make up a fake answer, or just go ahead and give us money for something like the $200 "Deluxe [fake] Service Animal ID Kit".
Alberta Health Services Medical Officer Dr. David Strong has urged the public to take precautions after a Calgary-area puppy was diagnosed with rabies. The five-month-old puppy came from Nunavut and had not been vaccinated against rabies. All those with whom the puppy had contact have been assessed and it doesn't sound like anyone required post-exposure treatment.
Since rabies is endemic in wildlife in the region, finding rabies in a puppy (especially when the puppy was presumably exposed elsewhere) doesn't mean that there's any greater risk to the public than there was before the case was identified. The imminent concern is the presumably limited number of people and animals with which the puppy had contact while it may have been infectious, but it's always useful to remind people about rabies and precautions they should take to prevent rabies exposure. In the infectious disease world, we often have to take advantage of high profile incidents to drive home some basic principles that we'd like people to pay attention to all the time.
Key rabies prevention points include:
- Avoid contact with wildlife.
- Keep your pets away from wildlife.
- Ensure your pets are up-to-date with their rabies vaccination.
- Make sure any bites from wild or domestic mammals are reported to public health so that it can be determined whether rabies post-exposure treatment is required.
Pretty basic. Common sense goes a long way with infectious disease prevention.
We've just posted a new info sheet about Capnocytophaga. One member of this bacterial group in particular, Capnocytophaga canimorsus, makes the news periodically because it can cause devastating infection in some individuals, like the Ottawa woman who lost three limbs after one of her own dogs accidentally bit her. This kind of severe infection, which is also sometimes called dog bite septicemia, is actually quite rare, but people with certain risk factors such as diabetes, alcoholism, and particularly lack of a functional spleen are at much higher risk. The bacterium very commonly lives in the mouths of dogs and cats, and is considered a part of the normal oral microflora in these animals. People are therefore commonly exposed to Capnocytophaga, yet infection is rare, but because it can be so catastrophic it's important to know the facts, especially if you or someone you know may be at higher risk.
You can read more about Capnocytophaga on the new info sheet, which you can find along with all our other info sheets on the Worms & Germs Resources - Pets page. You can also read about Capnocytophaga in the posts in our archives.
One of our most frequent pieces of advice on W&GB when it comes to kids is to always make sure they are supervised when they are around pets. This is important for at least two major reasons, one being avoiding potential high-risk contacts when it comes to infectious disease transmission (e.g. face-to-mouth, hand-to-bum), and the other being reducing the risk of injury (and subsequent infection) from bites and scratches. Children often don't know or aren't aware of the signs that a pet is stressed or uncomfortable, essentially forcing the pet to take progressively more drastic measures to get its message across, potentially ending in a snap or a bite. The problem is a lot of the time the supervising adult also doesn't know these signs, and thus many a bite or scratch may happen even when a parent is watching carefully from only a few feet away.
Yesterday I came across an excellent post on this very topic on another blog written by Robin Bennett, a certified professional dog trainer (CPDT-KA) in Virginia. Her post was very aptly entitled "Why Supervising Dogs and Kids Doesn't Work." Click on the title to see the entire post, but here are a few of the great points she makes:
- Watch for inappropriate child behaviour. In Robin's words, "Don’t marvel that your dog has the patience of Job if he is willing to tolerate [being poked, prodded, yanked, pulled, pushed, etc]. And please don’t videotape it for YouTube! Be thankful your dog has good bite inhibition and intervene before it’s too late."
- Intervene early. If the dog loses that loose, wiggly body posture and starts to stiffen up, don't wait until the animal has to escalate its message to growling or snapping to step in.
- Support the dog's good choices. If the dog chooses to move away from a child because it is uncomfortable, support that choice and don't let the child continue to follow the animal. If the pet can't get away, it may scratch or bite to try to make the child go away instead. Don't force the dog to make that choice. (This applies equally to cats or any other pet!)
It's very important for pet owners to educate themselves about basic pet behaviour, whether they have dogs, cats or other animals, and to teach that same information to their children. Another great program that teaches kids how to behave around dogs, and unfamiliar dogs in particular, is the "Be a tree" program, details of which can be found on the Doggone Safe dog bite prevention website.
So, Amy and I get home from soccer practice, and she gets in the house and yells “The dog pooped on the floor."
My thought: “That’s annoying.”
Amy: “..and it’s EVERYWHERE!”
My thought: “Great. One of the dogs has diarrhea.”
My next thought: “Oh crap… the Roomba.”
In case there was any doubt, it was made very clear that Roomba, the robotic vacuum, very effectively covers the entire floor surface. At least it was set up only to clean part of the house and not any carpeted areas.
My next thought: “What do I do now?”
I’m far from a germaphobe, but I really don’t want a lot of dog poop residue all over the floor. So, I picked up the chunks and did a couple rounds of mopping with a general household cleaner. Cleaning is the key aspect of disinfection. Physically removing debris gets rid of the vast majority of bugs that are present, and that greatly reduces any risk of pathogen transmission. Fortunately we don’t have any infants crawling around the floor or any high-risk individuals in the household, so that also reduces the concerns. If we did have a baby crawling around, I’d probably be more diligent and thoroughly disinfect any potentially contaminated areas with a good environmental disinfectant. As it is, I’ll probably stick with a few rounds of thorough cleaning with a good general cleaner/sanitizer.
How to disinfect a Roomba though... that's a different story.
The latest Worms & Germs infosheets are all about some common and not-so-common members of a particular group of parasites: tapeworms. There are a number of different groups and species of tapeworms that can infect pets, people, and other domestic animals, and sorting through which is which can be tricky, so we created a Tapeworms infosheet to help sort out the details.
There is one group of tapeworms in pets that is a particular concern from a zoonotic disease perspective. These parasites belong to the genus Echinococcus. Normally these tapeworms circulate in the wildlife population, mostly in wild canids such as foxes and various prey species, but they can also affect domestic dogs (and sometimes cats) that scavenge or hunt the same prey. In most cases the pet does not become sick, but people who are exposed to the tapeworm eggs in the pet’s feces can develop slow-growing cysts known as hydatid cysts or alveolar hydatid cysts. Over time these cysts can become very large and difficult to treat. There is also now evidence that one Echinococcus species (E. multilocularis) may be spreading - in 2012 a dog in Ontario was found to be infected with the cystic form of E. multilocularis (which is unusual in itself), but the animal had no history of travel outside of the province, therefore it was most likely infected via local wildlife.
Because echinococcosis can be such a severe disease in people, we created an additional infosheet focused on just Echinococcus. Both infosheets can be found on the Worms & Germs Resources - Pets page.
Image: Dozens of Echinococcus granulosus tapeworms from the small intestine of a dog. Although these adult tapeworms are tiny compared to some other species, this species can cause significant problems in people through the formation of hydatid cysts. (Photo credit: Ontario Veterinary College)
The word "ironic” gets used a lot, often incorrectly.
Alanis Morrissette’s hit song “Ironic” is a great example of this since she (ironically?) describes situations that aren’t really ironic, they just suck (i.e. winning the lottery and dying the next day isn’t ironic, it’s just bad luck).
Anyway, irony doesn’t have much to do with the topic at hand, apart from picking on the title of a news report “In ironic twist, dogs of local rabies survivor Jeanna Giese are exposed to bat that tested positive for the disease.” It’s not really ironic, but it’s an interesting story.
If anyone knows about the implications of rabies, it’s Jeanna Giese. She will forever be remembered in the medical world as the first person to be successfully treated after developing rabies. When she was 15, she picked up a (rabid) bat and was bitten. Not knowing any better, the family cleaned the bite wound but did not take her to a doctor. A little over a month later, she developed neurological disease. At that point in time, rabies was still called "invariably fatal," but she was treated with an experimental protocol that involved, among other things, putting her in a coma and treating her with antiviral drugs. Remarkably, she survived. More remarkably, she didn’t just survive, she was able to go back to school, learn to drive and function normally. (As a result of her miraculous recovery, rabies is now termed "almost invariably fatal.")
Jeanna has become an advocate for both animals and rabies awareness, using her personal experience to get her message across. Well, now she has one more personal experience to add to her repertoire.
Recently, she found a bat in the enclosure that houses two of her dogs. The bat was dead and covered in dog bite marks. Presumably in no small part because of her heightened awareness of rabies, she submitted the bat for rabies testing - and it was positive. So, her dogs were considered exposed. “How many people in the entire world can honestly say that a rabid bat has affected their lives twice in nine years?” she asks. Fortunately, her dogs were vaccinated against rabies and therefore they only have a relatively short observation period at home to go through, as opposed to a strict six month quarantine or euthanasia.
Awareness of rabies is the key, whether you’re trying prevent exposure of yourself, your family or pets. It’s also an area that needs improvement. As Ms. Giese said, "It's not surprising people know little about rabies... I didn't. You can't walk into a counselor's office and just pick up a pamphlet about rabies. I'm teaching kids that it's out there and what to do. Had I known what I know now, I would have made a different decision (about picking up the bat in 2004)."
Ironic? No, but a good story nonetheless.
I've written (whined, lamented, and complained) about this before, but it's rearing its ugly head again: fake service dogs. Essentially, it comes down to self-centred people who think they should be able to do whatever they want, and the inevitable fallout that can occur for people that truly rely on service animals.
It goes like this:
- I want to take my pet anywhere I go.
- I am the Centre of the Universe, so what I want must be provided.
- I pay some other selfish/greedy/unethical person to provide me with a badge, tag or other identifier that says my dog is a service dog.
- I take my pet wherever I go and if anyone questions me, I say "SERVICE DOG" as my get-of-out-jail-free card.
It's been going on for a while.
It's stupid and selfish.
It compromises real service dogs.
How? Service dogs are very well-trained animals that do an important job. They should have widespread access to places where regular pets are banned. However, when any idiot with $50 can get some form of service dog ID, there are going to be problems with some of these animals (e.g. disruption, bites) and the public, business owners and legislators may not realize the difference between a real and a fake service dog. Accordingly, if there is enough disruption (or a high profile event), there's the potential for problems (e.g. banning) for service animals that are truly needed.
A recent New York Post article highlights the issues with fake service dogs and shows an astounding degree of selfish behaviour. I always assumed that people who got fake service dog IDs would be quiet about it, because deep-down they know it's wrong or to avoid facing any negative public opinion.
Not Brett David, who enlightens us with comments such as
"I was sick of tying up my dog outside."
"He's been to most movie theaters in the city, more nightclubs than most of my friends."
"I don't care who you are, a teacup Yorkie will trump a black [American Express] card when you're trying to pick up a girl."
Or Kate Vlasovskaya, who isn't worried about people checking up on her fake service dog ID because "With all of that effort [required to find out anything], they will probably just let you in."
I'll bite my tongue here because anything else I have to say won't be good.
A colleague recently let me know about an article in the journal Infection Ecology and Epidemiology entitled “Human wound infectious caused by Nesseria animaloris and Neisseria zoodegmatis, former CDC Group EF-4a and EF-4b" (Heydecke et al 2013).
These are new bugs to me…
The article outlines an effort to characterize these bacteria from people with wound infections, most from dog bites. Thirteen bacterial isolates were studied - 11 were determined to be N. animaloris and 2 the related bacterium N. zoodegmatis. The authors concluded that localized infections occur most often, but severe complications can sometimes develop and that recovery is often slow (probably because of suboptimal treatment).
The true role of these bacteria in disease is unclear, since they might be missed by diagnostic labs or misinterpreted as being contaminants (and therefore not tested further or reported). These bugs tend to be resistant to quite a few antibiotics, so identifying them promptly is important to get the right treatment started.
There’s never a dull moment in infectious diseases. We’re constantly hearing about new pathogens. Sometimes, it’s because people just rename bugs about which we already know a lot. Sometimes, it’s because we realize that what we thought was one bacterial species is actually more than one. Sometimes, it’s because we realize that something we’ve dismissed as innocuous is truly a potential problem (so we start paying attention to it). Finally, sometimes truly new microorganisms are identified. With bacteria, the latter usually happens when someone first figures out how to identify an organism that’s been around for a while, but true emergence of new microorganisms can occur.
Anyway, whenever a new bug is found, it’s important to figure out how relevant it is. In this case, in the end, we’re still left with the main point being that the mouths of our domestic pets are cesspools of bacterial badness. Most often, our skin and immune system are able to prevent this from being a problem. However, when bites occur (or in other situations, such as licking wounds or when people have compromised immune systems), the potential for disease increases. Yet, it doesn’t really matter what the bug is - the key prevention points are the same:
- Reduce the risk of bites by good animal training, good animal handling and common sense.
- Promptly and thoroughly wash any bite wounds.
- If you have a compromised immune system, make sure you talk to your physician about any risks of pet contact and what to do in the event of a bite.
This report doesn’t mean that dogs are any higher risk to people than they were before. It just means we have a new name for a risk that’s been present for a while.
ProMed-mail usually posts a monthly recap of rabies cases in the US. The most recent one (like most of them) doesn't have anything too astounding, but it provides some good reminders.
Skunk attacks baby
A five-month-old baby that was outside in a car seat was bitten in the face several times by a skunk. The skunk was killed and tested positive for rabies. This is a high risk situation because it involves a young child and bites to the face. Because of that, the incubation period would potentially be very short so prompt treatment of the baby would be needed (and presumably post-exposure treatment was started right away).
Rabid family dog attacks
Five people were bitten by their pet dog, which was subsequently identified as being rabid. This should be a reminder that rabies exposure is still a concern with pets, that pets should be vaccinated, and that rabies exposure must be considered after any bite.
Fox + bite + electric hedge clippers = ...
A Virginia man was bitten by a fox, and he then killed the fox with hedge clippers (probably not a pretty sight). The bite did not break the skin (although the man did pass out afterward... not sure whether that was from fear of the bite or the aftermath). Anyway, the fox is only being reported as "presumed" rabid. Given the time frame of the encounter and the press release, I would have thought they'd know the rabies status of the animal, if it was tested. In the absence of knowing that the fox was not rabid, they'd have to assume that it was and take appropriate measures. Since the bite didn't break the skin, the bite shouldn't be considered rabies exposure; however, depending on how gory the subsequent fox-clipping was, there might have been exposure to infectious tissues by other means, and post-exposure treatment might have been indicated anyway.
Calf bites, animal health personnel screw up
Rhode Island health officials are trying to track down anyone that might have been exposed to a calf that lived next door to a popular ice cream shop. The calf bit someone and was quarantined. However, it died the next day and in a pretty major screw-up, local animal health officials didn't notify the state until 3 days later. By that time, the calf's body was too decomposed to be tested for rabies. So, it must be assumed that the calf was rabid.
A few take home messages:
- Rabies is still around... think about it.
- Vaccinate your pets.
- Avoid contact with wildlife, and if wildlife is behaving abnormally (e.g. attacking), rabies must considered.
- Make sure all bites from mammals are reported so that the need (if any) for rabies post-exposure treatment can be determined.
- Hedge clippers are not the best euthanasia tools.
Dogs have had some bad PR lately because of some high-profile bites and bite infections in people. So, in the spirit of fairness, I’ll write about a dog as a victim of an attack… from a cat.
Any infection characterized as "necrotizing" is bad. Necrotizing essentially means "dying," and any time you put "dying" in front of the name of a tissue or body part, you can assume the condition is pretty high on the "badness" scale.
In this case, the dog was a three-year-old Whippet that was bitten on the chest by a neighbour’s cat. The dog developed necrotizing cellulitis due to Pasteurella multocida, a bacterium that is commonly found in the mouths of cats, and one that not uncommonly causes cat bite infections in people as well. Within 24 hours of the incident, there was redness, swelling and pain over the area of the bite. The skin lesion progressed rapidly, with death of the skin over the affected area and development of large, deep skin ulcers, similar to what can happen in people with this kind of infection. Fortunately, the dog was successfully treated with intravenous antibiotics and survived.
Why did this dog develop necrotizing disease?
The reason one infection with P. multocida becomes necrotizing while another infection with the same bacterium does not is unknown The same is true for most cases of necrotizing fasciitis (aka flesh eating disease) in people, which is usually caused by Group A Streptococcus or by Staphylococcus aureus. While saying it's "bad luck" is highly unscientific, it’s about all we can say in most cases, since there are often no obvious factors that would predispose the affected individual to severe disease, and the bacterial strains that cause necrotizing infection are usually the same as those that cause mild disease and that are found in healthy individuals. So the "bad luck" explanation is about all we have to offer at this point.
The title gives it away: "Single, uninsured Ottawa mom loses three limbs to rare illness."
My first thought? Another Capnocytophaga canimorsus infection.
That's what is was - another rare but devastating infection cause by this bacterium, which can be found in the mouth of pretty much any dog.
People get exposed to C. canimorsus very commonly, but rarely does disease develop. The news article doesn't provide a lot of information from a medical standpoint. There's no mention of whether the woman in this case had any of the common risk factors for C. canimorsus infection, but it's highly likely. The big risk group is people who don't have a working spleen, as the spleen is an important immune organ that helps fight off infections by certain microorganisms, such as this one.
One notable statement from the article is "Since 1976 only about 200 septic shock cases caused by Capnocytophaga canimorsus have been reported worldwide, Health Canada says." I'm not sure from where that information came, and it might be something that is written on a Health Canada site, but you have to take statements like this with a grain of salt. Specifically, what does "reported" mean? Usually, they're talking about published case reports. However, most infections don't end up in the medical literature. This one presumably won't either, since (devastating though it was for the patient) it's probably a rather typical C. canimorsus infection. Considering how often there are news reports about these infections and the number of calls and emails I get about them, 200 cases over the past 20-30 years is a massive underestimation. That's not to say that C. canimorsus is common, a serious threat to the average person or something that's on the rise. It's just not as rare as some people may think.
Pet owners who don't have a spleen (or whose spleen isn't functional), have a compromised immune system or are alcoholics are the big risk group for serious infections by this bacterium. These individuals should:
- Know about C. canimosus
- Make sure their physician knows they own a pet
- Avoid contact with dog saliva, and
- Make sure that they seek medical care after any bite (not matter how minor it may seem)
Something I often discuss when doing infection control talks is needlestick injuries. The contrast between the approach to needlestick injuries (and blood exposure in general) in veterinary and human medicine is pretty astounding. In humans, there are strong educational campaigns, careful reporting, testing and treatment protocols, and increasing use of "safety engineered sharps devices" like retractable or guarded needles. In veterinary medicine, getting stuck with a needle is often considered "part of the job" and "no big deal". A study we did of veterinary technicians a few years ago found that 74% of techs had suffered a needlestick injury in the past year (Weese & Faires, Canadian Veterinary Journal 2009). I’ve had many such injuries during my career, pretty much all before I started to focus on infection control, and I honestly didn’t put much though into them (beyond ”oh crap, that hurt!”).
There are some valid reasons for the differences between human and veterinary medicine when it comes to needlestick injury prevention, not the least of which is the risk of HIV and hepatitis B virus transmission. In some ways, getting people to pay attention to needlesticks in veterinary medicine is tough because we don’t have viruses such as these in our patients. Needlesticks can cause pain, significant trauma and rarely severe (including fatal) problems (e.g. from drug reactions or infections), but the vast majority are rather inconsequential. However, a line that I frequently use is: “We don’t have an analogue of HIV or hepatitis B… at the moment. New diseases continue to emerge and you never want to be the index case.”
Is this really a risk? Well, yes. Beyond some new disease that could emerge and be a serious problem, we also have new issues being identified from bugs that we’ve known about for a while. Recent concern has been expressed about transmission of Bartonella species. This is a strange group of bacteria that are commonly found in cats and dogs. Bartonella henselae is the cause of cat scratch disease, a well-known problem, but Bartonella are attracting a lot more attention these days because they are being implicated in a range of often vague human diseases. Bartonella can be found in the blood of healthy cats (and to a lesser degree dogs), raising questions about whether a needlestick could result in transmission of these bacteria to people.
Two case reports highlight these concerns.
The first one (Lin et al, Vector Borne and Zoonotic Diseases 2011) tells the story of a veterinarian who developed a fever of unknown origin and back pain. Ultimately, he was diagnosed with Bartonella henselae infection which they speculated may have been transmitted following a needlestick injury. The needlestick link is weak here though. As a veterinarian, there are lots of other opportunities to be exposed to Bartonella henselae. It’s not uncommonly present in the blood of healthy cats and the main route of exposure is through fleas. Fleas feed on the cat, pick up the bacterium, then shed it in their feces. Cat scratches are a common route of transmission as the contaminated flea feces may be driven into the body. The veterinarian in the report didn’t recall having been bitten or scratched recently, but recall bias is an issue since scratches are common and often forgotten if not severe. Flea exposure wasn’t queried. Also, the needle with which he was stuck was a clean needle that had not been used yet. It still could have been the source of infection if it acted like a scratch, driving infected flea dirt on his skin into the wound, but I don't think this report is very strong.
The second article (Oliveira et al, Journal of Veterinary Internal Medicine 2010) describes infection by a different Bartonella speces, B. vinsonii berkhoffii, also in a veterinarian. The person was taking an aspirate from a mass with a needle and syringe and was poked in the finger as the dog was struggling. Five days after the needlestick, the person was still healthy. A blood sample was taken from the person and Bartonella was not found. However, by day 34 after the incident, the veterinarian reported having had frequent headaches for the past week, fatigue and some intermittent numbness in one arm. Bartonella vinsonii berkhoffii was detected in the person’s blood at that time. There was also an increase in anti-Bartonella antibodies between the two blood samples, which supports an active infection. The bacterium was not found in the tumour aspirate, but as a dog-associated bacterium and one that is rarely identified in people, and with the timing of exposure and disease, it’s quite suggestive that the needlestick was the source.
These may just be two reports, but they may just be the tip of the iceberg, because disease caused by Bartonella infections is often vague and probably routinely gets missed. There’s also increasing evidence of wide-ranging types of infection that may be overlooked, so people (and particularly veterinary staff) need to be aware and pay attention to the potential risk.
Needlestick injuries shouldn’t be considered part of the job. There are risks, but a little common sense goes a long way.
Information sheets on both cat scratch disease and needlestick injuries (and how to avoid them) are available on the Worms & Germs Resources - Pets page.
A few weeks ago, I did a talk about Schmallenberg virus for a government group. It was an unusual talk for me since it was about a disease that I’ve never seen, and a virus that as far as we know is not even present in North America. While I’ve been monitoring the issues with Schmallenberg virus in Europe, it was a good opportunity for me to look into the subject more thoroughly. One reason to do so is just academic interest, as someone who deals with infectious diseases. Another is because foreign diseases have a habit of becoming non-foreign, and that’s a serious concern with Schmallenberg.
Schmallenberg virus was first identified in 2011 along the Dutch-German border, so it’s a "new kid on the block." The virus is spread by insects called biting midges, and the disease affects ruminants (mainly cattle, sheep and goats). It causes two main problems: 1. diarrhea and decreased milk production in adults, and 2. adverse effects on the developing fetus in pregnant animals (causing abortion, stillbirths, and deformed calves/lambs/kids). The virus has rapidly spread across all of Europe and is now a major issue in some regions.
One important question about this virus is from where did it come? The answer is not clear. It’s important to figure this out to help determine where the virus might go. A midge hitch-hiking on a plane could be one way for the virus to make it to North America. However, a recent report from Sweden raises a few interesting questions.
Researchers at the Swedish Institute of Agricultural Sciences tested blood samples from 100 dogs. They found antibodies against Schmallenberg virus in 2 of them, and both positive samples were from the same dog that lived in an area where the virus has been found in ruminants.
What does this mean? It’s not clear yet.
- It might be of no consequence at all. It could just mean that an infected midge bit the dog and the dog’s immune system mounted an immune response to kill the virus.
- It can’t be dismissed that it could cause similar disease in dogs as in ruminants. I think that’s unlikely but it’s possible.
- Another concern is if, after being bitten, the virus can reproduce and reach reasonable levels in the dog’s blood (like it does in ruminants), then the dog could be another source of virus for more midges. It might not mean much in endemic areas where there are already lots of infected ruminants harbouring lots of virus. However, dogs travel more than ruminants, and if the virus can live in this species (whether or not it causes disease), then an infected dog could carry the virus to another country or continent. That’s my concern.
It’s incredibly easy to get a dog into Canada. That’s why we’re seeing various imported diseases in dogs, such as leishmaniasis. There’s not even a basic requirement (as in some countries) to mandate treatment for the concerning parasite Echinococcus multilocularis. So, there’s certainly going to be no testing for Schmallenberg virus (nor would this be practical). If European dogs can become infected and be infectious for a period of time, it’s quite plausible that dogs could be a source of international transmission. Fortunately, infected ruminants only shed the virus for a short period of time, so if dogs can be infectious, they’d hopefully following the same course. However, ever if they only shed for a few days, it’s still possible that they could be shipped across the ocean and find a waiting midge. Stranger things have happened with infectious diseases.
The New York Times has a nice article on hospitals that allow patient's pets to visit. This is a controversial area, with policies (when they are actually present) that range from wide-open access to complete prohibition. Like most things in life, there's a middle ground that's the most reasonable.
The positive aspects of people being allowed to have their animals come visit are pretty obvious, since people may have close bonds with their own pets and having a chance to see their pets might make a big difference to their mental state/well-being, particularly for someone who is chronically ill.
The negative aspects are less clear. We certainly know that pathogens can be transmitted from animals to people (and in the other direction too), and people in hospitals are often at higher risk of infection and complications thereof. There's a list of pathogens we worry about, but there's a serious lack of data to help determine the severity of the risk - and how to reduce it. Organized pet therapy programs are great because they are structured and there can be a lot of scrutiny and training of the pet and handler. Visits by patients' own animals are inherently less controlled, since the individual animal and handler don't undergo the same degree of assessment and training.
I get asked to review visitation guidelines frequently, and a reasonable middle-ground can usually be found. These are some snippets from the NYT article that highlight common points.
A doctor’s order allowing the family pet to visit is typically necessary...
That's a good approach, although it's not often used. This lets the doctor decide if it is reasonably safe to have the pet visit, i.e. the patient is not at a very high risk of infection. The weak link here is sometimes the doctor, because sometimes the doctor doesn't understand the risks associated with pet contact and may not identify a concern. Other times, the doctor may not understand the relatively low risk and the potential benefits, and therefore default to banning visitation without giving it much thought. I think that's less common these days but still an issue.
...as is an attestation from a veterinarian that the animal is healthy and up to date on all its shots.
The first part is great: making sure there are no health or behavioural issues with the animal that would pose an increased risk. The second part is very common but largely represents a lack of understanding of the issues. Too often, "has he had his shots?" is the main question that's asked about the animal, despite the fact that it's largely irrelevant from a zoonotic disease standpoint. Yes, we want to make sure the pet's rabies vaccination is up-to-date, but the other core vaccines are irrelevant from a human health standpoint (although they're very important for keeping the animal healthy overall).
Most institutions require that dogs — the most common visitors, by far — be groomed within a day or so of a visit and on a leash when they walk through hospital corridors.
Standard and logical policy. Grooming might help reduce the burden of bacteria, fungi and parasites on the haircoat, as well as a lot of loose fur and dander that could otherwise contaminate the hospital environment.
Cats must be taken in and out of the institution in a carrier.
Logical. Some cats do well on leashes but it's better to have a cat in a carrier when taking it through a strange area. It also helps prevent other people from coming into contact with it.
If a dog or cat wants to get up on a patient’s bed, a covering is laid down first.
Good policy, and it protects both the patient and the animal.
If an animal seems agitated or distressed when it comes into the hospital, staff members who meet the family and escort them to the patient’s room have the right to turn it away.
This has two important components. One is that the visitation is supervised, which is great. The other is that staff are given the ability to intervene in the unlikely even that there are problems.
If the patient shares a room with someone, that person must agree before a pet may visit.
This is often overlooked. Roommates might be afraid or allergic, and in those situations, visitation shouldn't happen in a shared room. There might be a way to do the visit in another room, so it doesn't necessarily preclude the visit from happening. This has to be broached in advance and in a manner that the roommate doesn't feel pressured into consenting. It's best done by having the patient's healthcare providers approach the other patient and/or the other patient's family.
There's always some risk with animal hospital visitation. That's never going to be eliminated, but a lot of common sense practices can reduce the risk to a very low level, hopefully to the point that the risk is overwhelmed by the benefits. A little structure and a lot of common sense go a long way.
It's maybe a sad statement that reading about someone whose diseased toes were gnawed off by their dog doesn't shock me anymore. It's not an everyday event but it's far from rare. An Indiana man learned about this the hard way when he woke up thinking his dog was licking his toes, when in fact, the dog had eaten them.
As is typical in cases like this, the person is a diabetic and had a foot infection, which contributed to the dog being attracted to the toes and the person not feeling the midnight snacking. Presumably, the person will be fine with some wound care and antibiotics. In fact, the dog may have just altered the manner of amputation if the toes were that severely affected. They may have been coming off one way on the other in the near future, but this is still not the desired approach.
A couple of questions come up sometimes in cases like this.
Is the man at risk of any infections from the dog?
- Certainly, there are concerns. This should be treated just like a bite since there was obviously contact between dog saliva and broken skin. Antibiotics were presumably already being used because of the toe infection, so that might have been enough, but antibiotic treatment would be needed in a situation like this given the type of exposure and the person's compromised state.
- Rabies is unlikely but it still has to be considered. This is just like a bite, so a 10 day observation period of the dog would be indicated. There's almost zero risk of rabies here, but when we're talking about rabies, "almost" isn't good enough.
Is the dog at risk of catching anything from the owner?
- This is perhaps the more likely of the two concerns. The dog was licking and eating infected tissue. Many of the bacteria that cause this type of infection can also infect dogs. The odds of the dog developing disease from this are pretty low. It's more likely the dog would become a carrier of the bacterium for a while (e.g. in its mouth, nose, or intestinal tract). If the dog is otherwise healthy, it's probably not going to suffer any consequences, but knowing what bacterium was causing the toe infection would help with that risk assessment.
While dogs amputating toes is rare, it's surprising how often I hear about people who let their dogs lick diabetic ulcers. As well, I've heard of people who have looked down and realized their dog or cat was gnawing on their toes (not amputating - at least not yet - but chewing away nonetheless). Usually, these are diabetics. Usually, nothing bad will happen. However, a dog's mouth contains many different bacteria that can cause severe illness given the right situation, and chewing on a toe of a diabetic patient in particular would fit into that "in the right situation" category.
Several dogs at a Miami humane society were quarantined last week because of concerns (or possibly panic/over-reaction) about methicillin-resistant Staphylococcus aureus (MRSA). MRSA in dogs is a concern because it's an important cause of infection in both people and animals. However, it's an opportunist, meaning it typically doesn't cause disease when it encounters a normal, healthy person or animal. In fact, a small percentage (~1-3% probably) of the human and pet populations carry this bacterium in their nose without knowing it, and the vast majority never suffer any consequences.
It's often tough to strike the right balance when dealing with an MRSA issue. We want people to realize that it's an important cause of disease and that it needs to be taken seriously, but we also want people to keep it in perspective and not freak out.
The Miami shelter report seems to be on the "freak out" side, particularly on the part of the local media.
It's not really clear what's happening based on this fairly poor article. The shelter's Chief Medical Officer, Dr. Maureen Swan, is quoted as saying there's a routine respiratory disease cluster in the shelter, but MRSA rarely causes respiratory disease in dogs. The article then adds Dr. Swan said it was "not the highly contagious MRSA virus." I have no idea what that means, and MRSA is not a virus.
My suspicion is that they have respiratory disease caused by the typical bacterial and/or viral pathogens that are commonly found in shelter dogs, and that they isolated a methicillin-resistant staph that just happened to be hanging around in that particular dog (since such bacteria normally live in the mouth, nose and skin). It's also not really clear whether this is MRSA. The article says MRSA, but the first thing I ask when I get an advice call about MRSA is "what staph species does the report say was isolated?". Most often, it's Staphylococcus pseudintermedius or another staph. These bugs can still be relevant, but they don't carry the same human health risk as MRSA, so it's important to know exactly what's been found.
Finding MR staph, including MRSA, isn't unheard of in a shelter. It's just one of many reasons that good general infection control practices are needed in these facilities. When MRSA is found, taking some extra precautions is reasonable because of the potential for disease and transmission to people, but too often people panic. It's understandable based on concern about MRSA and the scary stories people can find with a quick Google search. Not uncommonly, there's a combination of an short-term overly aggressive response while at the same time failing to improve basic infection control practices, which are the most important.
More information about MRSA can be found on the Worms & Germs Resources - Pets page.
An abstract for the upcoming CSTE (Council of State and Territorial Epidemiologists) conference in California describes a rare but concerning case of Brucella canis infection in a child. All I have to go by is the abstract (since the meeting hasn’t happened yet and I won’t be there anyway), but it provides an interesting outline.
Brucella canis is a bacterium that is (not surprisingly, given the name) associated with dogs. It’s present in dogs internationally, with higher rates of infection in strays and shelter dogs. It can cause a variety of problems in dogs, most often abortion, stillbirth and birth of weak puppies, but also things like reproductive failure and genital inflammation in males, and diskospondylitis (a kind of back problem). After a dog gets infected, the bacterium can localize to genital tissues, where it tends to hang out, resulting in intermittent shedding of B. canis in urine, vaginal discharge, fetal fluids, semen and, to a lesser extent, some other tissues. Humans can then be exposed via contact with these fluids. The main risk to humans comes from handling breeding dogs, particularly female dogs that have aborted puppies. However, people seem to be relatively resistant to B. canis infection, and there are actually only a small number of reports of human infections with this bacterium.
The risk to average pet owners is very low, but as this report shows, low doesn’t mean zero. This abstract deals with an infection in a 3-year-old child from New York city. The family had acquired a Yorkshire terrier puppy from a local store in March 2012. As is expected, there was close contact between the child and the puppy.
Near the end of April, the child was taken to an emergency room because of fever and difficulty breathing. Bacterial infection wasn’t the main suspect and he was discharged without antibiotics (presumably having improved from how he was at the time of admission). However, a blood culture was collected and it came back positive for Brucella canis. While the boy had been doing well, he was treated with 45 days of antibiotics to try to make sure the bacterium was eliminated, since it can cause chronic problems.
In a step that’s too often overlooked in zoonotic disease occurrences, there was an investigation of the source. That’s not surprising since this is a rare and concerning bacterium, and it’s pretty clear that pet contact tracing is required. The puppy was healthy but the bacterium was isolated from its blood. Because of the test result, the puppy was euthanized. (There’s no mention of whether this was at the owner’s request or based on the recommendation of public health personnel.)
The source of the puppy was a major concern, since it’s important to make sure that there aren’t other infected puppies around. The puppy came from a "commercial breeding facility" in Iowa - yet another instance of the potential for widespread national and international distribution of pathogens from large commercial pet operations. The facility was quarantined but there’s no more information in the abstract about whether other positive animals were found, whether infected puppies may have been sent elsewhere in the country, and what measures were taken to correct the problem.
A littermate of the New York puppy was sold by the same store. It also tested positive for B. canis and was treated.
This is a rare incident, but it highlights some points for me:
- Large commercial breeding facilities for dogs are unnecessary and create increased risk of disease in animals and by extension people. Yes, this could occur with a small private breeder, but the more animals, the more risk of infectious disease, and the larger the facility, the larger the potential impact should a disease issue develop.
- Proper counseling of people whose pets are diagnosed with a zoonotic pathogen is needed. I don’t know the story at all about why the first puppy was euthanized, but it might have been avoidable. What to do with animals that are healthy but shedding potentially concerning pathogens is a tough area to address. That’s particularly true for a bug like B. canis, since it can be hard to eliminate.
- Good communication is needed between the medical field, public health, veterinary medicine and the public. It’s hard to say how smoothly this investigation actually went, but it shows a good response to a rare but potentially serious problem.
- People that sell animals need to keep accurate contact information from purchasers. It’s good to see that they were able to track down the owners of the original puppy's infected littermate. Contact tracing is important with infectious diseases and it can be exceedingly difficult at times.
- There’s an inherent risk in pet ownership. We know that and have to accept it. The child was high risk because of his age. That doesn’t mean we don’t let kids have pets, but we have to understand the risk and use some basic hygiene practices to reduce that risk. Would it have had any impact on this case? Who knows, but it never hurts to improve.
Studies that look at risk factors can be pretty variable in terms of what they tell you, the impact they have and how accurate they are.
Some findings are pretty logical, clear and indicate something that should be done.
- Smoking is a risk factor for [insert many diseases here], so to reduce the risk of [whatever disease], stop smoking.
Others make sense but don’t necessarily lend themselves to an effective intervention.
- Being male is a risk factor for cardiovascular disease... not much I can do about that.
Sometimes, you have to remember that a risk factor for one thing doesn’t provide a clear answer when a broader context is considered.
- Moderate consumption of red wine can reduce the risk of various conditions, but alcohol consumption can also increase the risk of other conditions.
Sometimes, how the study is designed and performed can really affect the results.
- If I did a large study of the general population in Guelph, I could presumably show that going to a hospital greatly increases your risk of death. Does that mean you shouldn’t go to the hospital? No, because I could presumably also show that if you have chest pain and go to a hospital, you’re more likely to live. Knowing the study population and what question is really being asked are critical.
Sometimes, something that’s found to be a risk factor isn’t really the risk factor, but it’s associated with something else that is.
Sometimes, something can be "statistically significant," but of limited consequence.
- If doing something increases the risk significantly, but only by 0.0001%, does that mean anything?
Why do I write this? Because these are some of the things that we have to think about when assessing risk factor studies. While one Toronto radio station loves to give 10 second snippets on some new risk factor medical study, you can’t determine much about the study itself from a sound-bite (or internet post). You need to think about the details regarding how the study was done. Nevertheless, risk factor studies can provide useful information, but consider the results carefully, whether they are relevant, whether they indicate changes need to be made or whether they indicate that we need to look at the issue further.
The first study compared dogs from northern California that had or didn’t have leptospirosis. They found a few things:
- There were differences in geographic distribution of the lepto cases and controls. That makes sense since we know lepto varies regionally, but living in different areas might also be associated with different behaviours and contacts (e.g. wildlife contacts).
- There was a temporal cluster, with more cases occurring between May 2003 and May 2004, compared to the rest of the 2001-2010 study period. That makes sense too since we see variation in cases within and between years.
- These results don’t change anything, but are an indication of what work needs to be done next. Looking at why things vary geographically and temporally might be important for figuring out how to reduce the risk of disease. It also indicates regions where more efforts to educate pet owners (and veterinarians) are indicated, and where vaccination is more important.
The second study looked at dogs from Kansas and Nebraska, with and without leptospirosis. They also found a few risk factors.
- Lepto was more common in houses lacking complete plumbing facilities. Presumably, this is a proxy for something else. Poor plumbing doesn’t likely result in lepto in dogs. Rather, it presumably means that a dog living in a house with poor plumbing has some other factor that increases its risk. For example, incomplete plumbing may be more likely in lower socioeconomic (i.e. lower income) households, which might then correspond to other more direct risk factors for the dog (e.g. poorer nutrition, less veterinary care). It could also be that houses lacking complete plumbing tend to be in a different area where there’s more exposure to wildlife reservoirs. A couple of other indicators of poverty status were also significant, highlighting the potential impact of owner poverty on pet health.
- Dogs that lived within 2500 m of a university or college, or a park, were also at increased risk. The park risk factor makes sense since they could be exposed to sites infected by wildlife reservoirs (e.g. raccoons). Living close to a university or college is tougher to figure out. Maybe it’s associated with economy, as students are typically at lower income levels. Maybe it’s because colleges and universities usually have lots of green space that might harbor wildlife.
So, these studies tell us some new information, reinforce some previous knowledge (or perceptions) and raise some new questions that we need to answer. By themselves, they won’t result in major changes in how we try to prevent lepto in dogs, but little steps is typically how science progresses.
As someone who works with zoonotic diseases, I often find myself fighting battles on both sides of the issue. One side is trying to increase awareness about zoonotic diseases (i.e. those caused by microorganisms that are transmitted between animals and humans) and getting people to think about the potential role of animals in human infection. However, I often also have to deal with trying to keep things in perspective, and prevent people from over-reacting to disease risks. Part of this is helping people understand that disease transmission is typically a two-way street. While animal-to-human transmission is usually the greatest concern, human-to-animal transmission of a variety of bugs also occurs, and this can cause problems for the animals, and for people who subsequently have contact with those animals.
A recent paper in the journal Mycoses (Van Rooij et al 2013) highlights one such scenario. The paper describes ringworm in a dog that was associated with the fungus Trichophyton rubrum, which is not the typical ringworm species (Microsporum canis) that we find in dogs. Trichophyton rubrum is a common cause of infection in people, particularly tinea pedis (athlete’s foot) and onychomycosis (fungal infection of finger and toe nails). The authors did something that’s often lacking in reports of animal-human transmission: they actually tested both the person and the pet. Here, they found that the owner was a carrier of this fungus. They were able to isolate the fungus from his skin and determined that he likely had an asymptomatic infection that was subsequently transmitted to his dog. (He’d previously had untreated and self-resolving athlete’s foot, and presumably remained a carrier after that). Since this ringworm species is predominantly found in humans, it’s a reasonable assumption that it started with the person and the problem was only identified when the dog developed disease. In this case, the dog was old and had been treated with corticosteroids, both of which probably affected it’s immune system and made it more susceptible to this uncommon cause of canine disease.
It’s important to remember that while zoonoses are important, pathogens go both ways.
In the end, we’re all animals.
The first true confirmed canine influenza virus (CIV) was the H3N8 canine flu that evloved from H3N8 equine flu. That's the virus that spread to and amongst dogs in various parts of North America. The general consensus has been that only this strain should be called CIV, since it's been the only true dog-adapted influenza virus that's developed the ability to stay and circulate in the dog population.
More recently, another canine flu virus has emerged in dogs, this time a type H3N2 in Asia. H3N2 is a common human flu type, but birds are the ultimate reservoirs of all flu viruses, and based on the genetic relationship of H3N2 from dogs and birds, it's thought that this virus came to dogs from birds.
Anytime a new infectious disease is encountered, it's important to figure out who/what it can infect. When H3N8 CIV emerged, it was shown that even though it came from horses, it was no longer adapted to readily infect horses. So, knowing a virus' origin or typical infection trends can be useful but it doesn't necessarily tell you the whole story.
Cats and ferrets are susceptible to many different types of influenza viruses, and are good species to look at when figuring out if a virus can spread to other domestic animals. A study in the recent edition of Influenza and Other Respiratory Viruses (Kim et al, May 2013) looked at transmission of H3N2 CIV between dogs, cats and ferrets.
In that study, researchers infected dogs with CIV and kept them in close proximity to cats and ferrets, but without direct contact. They also infected cats and ferrets to see whether they could transmit the virus to other cats or ferrets.
Here are some highlights from the study:
- All directly infected animals developed some degree of illness, with cats and dogs typically developing sneezing, coughing, increased respiratory effort and nasal discharge, and ferrets only developing sneezing.
- Cats could become infected by being in proximity to both infected dogs or infected cats.
- Ferrets didn't get infected when exposed to infected dogs.
- Ferrets did not develop disease after exposure to an infected ferret but 2/3 developed antibodies against CIV, meaning the virus had been transmitted, but not able to cause disease.
- Cats shed higher amounts of virus than ferrets.
- Dogs stopped shedding the virus by day 8 after infection. That's not surprising since influenza shedding is short-term with H3N8 CIV. It shows that use of good infection control measures, particularly isolation, can be a key component of canine flu control.
- Dogs with H3N2 CIV are potential sources of infection for cats and ferrets.
- Cats that are exposed to the virus can get sick and be sources of infection for other animals, presumably including dogs. Cats may be another truly susceptible host for this virus.
- Ferrets seem pretty resistant to the virus. It probably takes fairly high level exposure for them to get infected and they are less likely to be of concern for subsequent transmission.
Interspecies transmission of flu viruses, and other viruses, is obviously an issue. Most of the attention is paid to the bird-pig-human cycle, for good reason. Birds are the reservoirs of all influenza virus variants, pigs are susceptible to both human and bird flu viruses and can act as a "mixing vessel," and humans are the species we're ultimately most concerned about. However, the potential for disease in pets and for pets to be reservoirs of influenza for people or other animals shouldn't be neglected. I've frequently had discussions with colleagues in the medical and public health fields about the need for parallel companion animal surveillance when plans are made for emerging infectious disease surveillance and response (e.g. SARS, H1N1 flu, novel coronavirus). They typically respond with general enthusiasm, but interest and application aren't the same, and actually getting plans in place to perform coordinated parallel surveillance hasn't happened. Studies like this are just one more piece in the puzzle that indicate the need for broader surveillance and consideration of pets.
Surprise, surprise - Meg has a hot spot.
"Hot spots" (aka focal bacterial pyoderma) are common skin infections in some dogs. Meg has underlying skin issues and lately has spent a lot of time wallowing around in ponds (because that's what she likes to do). With her skin issues, potentially weaker immune system because of her advanced age, and frequent wetness, she's a bacterial skin infection waiting to happen.
The latest hot spot is under her neck, and was evident by some colour change in the area (picture #1) and a bit of scratching, along with an odour if you get really close. These signs can easily be missed, especially early on, as the infected site is a bit hidden. Often, people only notice when it gets really wet and stinky, or when the dog scratches at it incessantly. Clipping the area revealed a more extensively affected area (picture #2) and a couple of focal spots with some pussy discharge. (It's quite amazing what can be hiding under an animal's fur!)
A hot spot is caused by a bacterial infection, and it's almost guaranteed that it's a staph infection (most likely Staphylococcus pseudintermedius). I took a swab from the affected area for culture. That's probably not critical in a case like this, especially when I'm going to treat it topically and without antibiotics, but since I can do it myself, it never hurts to have the information with regard to what bug is responsible (particularly if the infection comes back again).
The approach to treating hot spots is pretty straightforward, and owner compliance is key. Here's the plan:
Clip the area
- This helps identify the extent of the problem. It also (very importantly) helps keep the area dry and facilitates topical treatment.
Keep the animal from traumatizing the site
- That's been easy so far with Meg since she's not really scratching at it. If she was scratching, we'd need to put on an Elizabethan collar or use some other form of protection. In some cases, corticosteroid anti-inflammatories are needed to control the itch (and thereby the scratch).
Keep it dry
- Easier said than done. Despite being old and lazy, Meg is very motivated when it comes to lounging around in whatever water she can find (including the other night at 3:00 am... don't get me started on that one). Other than that, since the site is clipped now, keeping it dry is not a major problem.
- This is a bacterial infection, but the advantage of skin infections is that skin's on the outside. We can treat it topically and avoid using oral or injectable antibiotics. There are various things that can be done this way, usually involving bathing, wiping or spraying the area with topical antiseptics. We're using an antiseptic spray on Meg.
- Nothing major. It's unlikely that the cause is something zoonotic (and if it's MRSA, she presumably got it from someone in the family!). The staph that typically cause these infections are common inhabitants of canine skin. They rarely, if ever, cause infections in the absence of some inciting cause so Merlin (the other dog) and Finnegan (the cat) are unlikely to get an infection from Meg in this situation.
- A little handwashing goes a long way.
Hopefully I don't get to write about the massively increasing hot spot next week.
Cranimals Organic Pet Supplements has launched an at-home urinary test kit for dogs and cats that lets you "Monitor and track your pets health in an accurate and economical way, avoiding costly, unnecessary trips to the vet" (while not avoiding costly, unnecessary supplements, I assume).
The test claims to diagnose urinary tract infections (UTIs) by "detecting blood, leukocytes (AKA white blood cells) and nitrite in animal urine." Unfortunately, it cant.
- Blood in the urine does not necessarily mean there is an infection (i.e. this is a non-specific sign). In fact, a minority of cats with blood in their urine have an infection. They are much more likely have another problem like idiopathic cystitis that needs to be treated differently than an infection.
- Urine test strips for white blood cells are notoriously useless in animals. Maybe they have a better, more useful version, but I doubt it. The best way to detect these cells in the urine is to look for them using a microscope.
- Nitrite can be produced by bacteria in the urine but it has little to no diagnostic value in dogs and cats.
There's no mention about any specific evaluation of the test (i.e. they haven't checked to see if the test actually does what it's supposed to). By the look of the picture, it seems to simply be a urine dipstick in a fancy holder marked up a couple thousand percent to make money. Actually, it seems to be an inferior type of dipstick since it only tests for 3 things, two of which are useless.
Not surprisingly, the test is to be used in conjunction with their supplements (which probably explains why a supplement company decided to enter the diagnostic testing business).
The test isn't exactly cheap either: $39.95 for dogs and $49.95 for cats (the only difference to me being the cat kit comes with a bit of non-absorbent litter to put in the litterbox to collect urine, with a nice markup there too). While marketed as a way to save money on veterinary bills, think hard about what it will really do. Beyond potentially providing misleading information that could impact proper care, it will probably end up costing owners more:
- If the test is negative and the pet has urinary tract issues, it needs to be seen by a veterinarian to find out what's going on.
- If the test is positive, the pet needs to be seen by a veterinarian to get treated. No competent veterinarian is going to prescribe a treatment based on an at-home test like this. So, the full range of testing will be done anyway.
Ultimately, if the pet is sick, it needs to see a veterinarian. If it's not sick, there's no indication for testing like this.
If you want to know some real facts about diagnosing UTIs in dogs and cats, check out the International Society for Companion Animal Infectious Diseases Guidelines for diagnosis and management of UTIs in dogs and cats.
If you still think this test is worth the money, I've got some great oceanfront property in Saskatoon that I'll sell you (see photo). The water skiing is particularly good in January.
This is an increasingly common question, because MRSP is increasingly common. I've had two calls about it this week, and it's only Wednesday.
It's a good question to ask because MRSP (methicillin-resistant Staphylococcus pseudintermedius) is a highly drug-resistant bacterium that causes a lot of problems in dogs, and because of the high profile of its relatively distant relative, MRSA (methicillin-resistant Staphylococcus aureus), in people.
The short answer is: Yes, MRSP can infect people
BUT... (and it's a big and important but):
It's exceedingly rare and the overall risk is very low.
Here's my reasoning behind this answer:
1) Reports of MRSP infections in people are very rare.
- I think there are only two such published reports at the moment. There have probably been more infections than the number that are published, and there's the potential for MRSP to be misdiagnosed by some human diagnostic labs (meaning some MRSP infections may be mistaken for something else), but I think it's fair to sayl this a very rare infection in humans.
2) MRSP is not well adapted to infect people.
- MRSP is not inherently any more likely to cause infection than methicillin-susceptible strains of S. pseudintermedius (MSSP).
- MSSP can be found on basically every dog.
- A large percentage of the human population has contact with dogs every day.
- So, a large percentage of people encounter MSSP every day. Yet, reports of MSSP infection in people are very rare. To me, that indicates that this bacterium is poorly adapted to be a human pathogen.
3) Veterinary dermatologists are not extinct.
- MRSP is very common in dogs with skin infections. In some practices, it's the main cause of these infections.
- That means veterinary dermatologists encounter a lot of MRSP every day.
- I have yet to hear a report of a veterinary dermatologist getting an MRSP infection (carriers yes, disease no). I wouldn't be surprised if there actually have been some infections, but dermatologists can be considered the canaries in the mine when it comes to human MRSP risk, and I'm not aware of any real issues.
4) All dogs are biohazardous
- While this may not comfort the people calling me who are worried about the health of their families, it's important to put things into perspective. All dogs are carrying multiple microorganisms that could cause disease in people under the right circumstances (and the same goes for all cats, horses, people etc. for that matter).
- If you screened the average dog, you'd find things that are of greater concern that MRSP. In fact, MRSP probably barely cracks my "Top 10 List" of things I'm worried about the average dog spreading.
So, yes, there's a risk of MRSP infection when a person has contact with a dog infected with or carrying MRSP. There's also a risk of infection from methicillin-susceptible S. pseudintermedius, the version of the bug that basically all dogs carry, and a whole range of other bugs.
There will never be a zero-risk pet when it comes to zoonotic diseases. It's impossible. The risks may be very low but we can never eliminate all risk, just like we can never eliminate all risk from walking down the street. For some people, that slight degree of uncontrollable risk might be too much to handle, and they probably shouldn't own a pet. For most, the positive aspects of pet ownership outweigh the risks, and some basic hygiene practices (e.g. handwashing, avoiding licking, avoiding contact with the dog's mouth, nose and bum) can reduce that already low risk even further.
Merlin’s been a great dog so far, but despite that, there’s no need to propagate his genes. So, Monday was the big day… neuter time! As expected, since returning home he’s been feeling sorry for himself, but otherwise so far, so good.
Being someone who deals exclusively with infectious diseases and does surgical site infection (SSI) research, I have to think about his risk of developing an infection and how to prevent that.
Infection rates after neuters are very low. Actually, I can’t say that with confidence since we don’t have good data to back it up. We just finished one of the largest surgical site infection surveillance studies in dogs and cats, but being based at a tertiary care referral hospital, we didn’t get any data on neuters. I’m not aware of any private-practice-based studies that have assessed SSIs in dogs and cats, so my initial statement is just based on the fact that I don’t hear much about SSIs after neuters, and when I talk to people in primary care practices, they don’t report many of these infections. They occur, but they probably are truly rare.
However, rare doesn’t mean it will never happen, so pet owners need to be aware of what they can do to reduce the risk of post-operative infections (and then actually do it).
It’s been said in human medicine that the most critical time for preventing (or causing) SSIs begins and ends in the operating room. I think that’s true for animals as well, so there’s not much that the pet owner can do about that part except choose a good veterinarian, and not be afraid to ask pointed questions about the clinic's infection control measures. The pet owner’s major role is taking care of the animal after surgery. Here are a few things that I need to do for Merlin:
- Restrict his exercise for a few days. Trauma to the incision site will increase inflammation and the chance of an opportunistic infection developing.
- Keep him from swimming (or more accurately, wallowing in the swampy areas and ponds around home). Keeping the incision dry is important for good wound healing.
- Keep him from licking the wound. This a huge factor and one that people often mess up. Yes, he hates his Elizabethan collar (i.e. the head cone). However, it’s important that he wears it to keep him from damaging the incision site and seeding it with bacteria from his mouth. It’s a matter of short-term pain (annoyance, actually) for long-term gain.
- Keep an eye on the incision. A little inflammation (e.g. redness, swelling) is normal. If it increases or any discharge develops, that might indicate a developing infection. If that occurs, getting him re-evaluated ASAP is important.
- Make sure he goes in for his recheck, and that it’s done on time. This is important to detect problems in a timely fashion and to remove his sutures. (Merlin will presumably get his "recheck" at home, since the two DVM degrees Heather and I have hopefully give us the collective ability to remove a few stitches ourselves and determine if the incision is healing okay.)
None of this guarantees Merlin won’t get an infection, but these measures are all important. There is a non-preventable fraction of infections - meaning some will occur despite everything you do. However, a large percentage of SSIs are preventable and these basic practices can help.
While this morning's -7C temperature and snow don't exactly make me think about sandboxes or wandering around barefoot, warmer weather will presumably occur someday and the risk of outdoor exposure to parasites will start up again.
Since nothing says summer like hookworms, here's a new info sheet all about hookworms, including information on cutaneous larva migrans. The sheet can also be found on the Worms & Germs Resources - Pets page, along with info sheets on many other topics.
Business Mirror, a Philippine news website, had a recent article entitled "Rabies: deadlier than ever". That's a bit like saying Decapitation: now an even worse idea. Rabies isn't 'deadlier than ever,' since it's hard to get deadlier when the disease is already almost invariably fatal.
Anyway, beyond quibbling about the title, there are some interesting parts to the tragic story.
The article describes the death of a young boy. He was attacked by a dog while playing in his front yard in the Philippines. After the attack, he was taken to the hospital where, while he treated for some large scratches, he was not treated for rabies exposure because there were no bites.
This isn't too surprising, since it's an area in which there are some education gaps and misconceptions. The main risk for rabies transmission from dogs is from bites, since the virus is present in high levels in saliva, and bites directly inoculate saliva into the body. Rabies contaminated saliva deposited on intact skin isn't a risk. Rabies virus shouldn't be hanging out on a dogs paws, so it's easy to see how the transmission risk from scratches might be overlooked. However, during an attack, saliva contamination of the skin and a scratch that breaks the skin can both occur, thereby inoculating rabies virus into the body just like a bite.
Presumably that's what happened here, because 2 months after the attack, the boy developed rabies. It started with severe itchiness over the site of the scratch, and he was dead two days later.
We can't play around with rabies. If there's potential that an animal interaction led to rabies exposure:
- The animal must be identified and either euthanized so its brain can be tested, or (if a dog or cat) quarantined for 10 days to ensure that it does not exhibit any signs of rabies.
- If the animal can't be identified and quarantined or tested (or if it's positive for rabies), proper post-exposure treatment is required.
More information about rabies can be found on the Worms & Germs Resources - Pets page.
“Is MRSP zoonotic?” That’s a question I get all the time. MRSP (methicillin-resistant Staphylococcus pseudintermedius) is a canine staph (a bacterium) to which people are exposed all the time. Yes, it can infect people, but only very rarely, particularly when you consider how often they’re exposed. Nonetheless, human MRSP infections can occur.
My typical answer to the question is “Yes, but…” followed by an explanation of the overall low risk. My general line is:
- It can be transmitted to people.
- Human infections are very rare
- There’s no use panicking over MRSP or being draconian when you have an infected animal.
- At the same time, no one wants a highly resistant infection, so some basic measures should be used to reduce the risk of transmission.
Issues are also greater when people with compromised immune systems are involved, and a recent paper highlights this.
The paper (Savini et al, Journal of Clinical Microbiology 2013) describes MRSP infection in a 65-year-old man who was immunocompromised because of a bone marrow transplant. He developed a wound infection, and his physicians and the diagnostic lab did a pretty comprehensive study of the bacterium they isolated from the wound, ultimately determining it to be MRSP.
The man lived “close to a pet dog and farm cows," whatever that means. The dog was probably the source, but unfortunately (as is common) no efforts were made to see if the dog was carrying MRSP, to see if the cows were positive for MRSP (since this bug can rarely be found in cattle), or to type the isolate to see how it compares to strains that are typically found in animals.
Will this report change my answer to the first question? No. It gives me another example of a human MRSP infection, but such events are still exceedingly rare and this individual was highly immunocompromised, having graft-vs-host disease after his bone marrow transplant.
We don’t need to be afraid of MRSP, but we need to realize there is some risk, and the risk is presumably higher for certain people (e.g. very young, very old, people with compromised immune systems). We therefore need to use some basic infection control and hygiene practices to reduce the incidence of transmission of MRSP and other potentially harmful microorganisms from animals to people.
More information about MRSP can be found on the Worms & Germs Resources - Pets page.
Following outbreaks of campylobacteriosis in a Canberra, Australia nursing home, health officials have recommended banning puppies from aged care facilities. Two outbreaks that involved at least 15 people occurred in one such facility last year, and a healthy puppy was identified as the cause. Unlike many reports in which people try to blame an animal source without any evidence, they isolated Campylobacter jejuni from the puppy and people. That, along with ample previous evidence of a role of puppies in this disease, is pretty strong evidence that the puppy was the problem.
They concluded that puppies shouldn't be aged care companions because of "high rates of Campylobacter carriage and shedding, their social immaturity, susceptibility of elderly residents to infection and poor outcomes." Such a conclusion is not really that surprising or novel, actually. The 2008 international guidelines for animal visitation in hospitals recommend that only adult dogs and cats should be used for these activities, for several good reasons:
- Puppies are biohazardous. It's just biology. Young animals are at much greater risk of shedding various bacteria that can cause disease in people, such as Campylobacter.
- Contact with puppies and kittens has been clearly demonstrated as a risk factor for diseases like campylobacteriosis.
- Compared to adult animals, puppies and kittens are more likely to poop on the floor.
- Puppies and kittens are also more likely to nip or scratch through playful behaviour.
This is not to say that everyone should avoid puppies and kittens, after all they are cute and entertaining, and a great pet in many situations. The risk is higher in certain populations, such as people living in nursing homes, and while puppies are fun, similar positive impacts can be obtained by well-run visitation programs using older animals. That's the approach that being taken in Canberra, as trained adult dogs will still be allowed to visit aged care homes (hopefully as part of a structured program).
Lately there has been a run of pet treat recalls due to Salmonella contamination (with the latest one courtesy of "Diggin' Your Dog"), but it shouldn't come as much of a surprise. Salmonella contamination of raw animal-based pet treats has been reported for years. It's not just a risk to dogs, since outbreaks of salmonellosis in people from handling treats have also been reported. Despite some good moves by the industry to improve the situation (e.g. better manufacturing practices, more products being irradiated), treats still need to be considered high-risk for being contaminated with Salmonella and other bacteria.
So, what can be done to reduce the risk?
- Buy individually wrapped or pre-packaged treats. Treats from bulk bins are higher risk because one contaminated item can cross-contaminate many others. Also, bins are often continually topped up without cleaning or disinfection so contamination can persist.
- Choose products that have been irradiated. There are still some baseless fears about irradiation, but there is absolutely no evidence that irradiation of food is harmful and it can effectively kill pathogenic microorganisms.
- Avoid feeding raw animal-based treats that have not been irradiated to animals at higher risk of becoming sick or having a serious infection. This includes elderly animals, puppies, pregnant and nursing dogs, dogs that are immunocompromised (e.g. undergoing chemotherapy) or dogs that have chronic intestinal disease. Also, they should not be fed to dogs that have contact with high risk people, such as those that live in households with infants, elderly individuals, pregnant women or immunocompromised individuals. Also, they shouldn't be fed to dogs that visit human hospitals. One study showed that dogs fed raw animal-based treats had a 12-times greater likelihood of shedding Salmonella (Lefebvre et al 2008).
- Wash your hands after handing pet treats.
If in doubt, or if your dog or family fits into one of those high risk groups, stick with processed treats that have been cooked or make your own cooked treats.
Some people like to send me links to internet sites to see if they can get a rise out of me. There are a few usual suspects (both senders of information and places I get sent to) but a new one for me was tlcpetfood.com
For some reason, this site has a series of FAQ's completely unrelated to pet food. Some are rather bizarre, such as "My dog keeps getting pneumonia, and we just found out her internal organs are on the wrong side. Help? "
Many of the answers are fine. That's because they're plagiarized... verbatim text taken from reputable sites (mainly AAHA's Healthy Pet site) without attribution. Besides the whole violation of intellectual property aspect, it's at least good that the advice is sound.
Some of the other answers they provide (likely the ones that aren't plagiarized) are considerably less sound.
The one that got sent to me was "Is it okay for my dog to lick my son's face?"
This is actually a common question and a reasonable one. There's no perfect answer to it, but there are definitely some imperfect answers, such as this one:
(It starts out okay...)
Yes, it probably is.
- I'd agree with that statement.
(Then goes downhill quickly...)
The only disease that dogs and humans can pass back and forth through saliva is beta strep throat, which is relatively rare.
- This is a myth that just won't go away. There's no evidence that pets are relevant sources of strep throat. Furthermore, there are many other pathogens that can be transmitted from dogs' saliva to people. Disease isn't common but it does occur and it can be fatal in some situations.
And if your son has a weakened immune system, you may want to be careful about exposing him to the normal bacteria that's present in the saliva of healthy dogs.
- Good advice. (However, if their statement that strep is the only thing that can come from dogs was actually true, this one wouldn't make any sense.)
My response to this common question is that I don't particularly like being licked by my dog. It's a personal thing and not a germaphobic response. It's unlikely to harm me as an adult with a (hopefully) functional immune system. I don't hover around my kid to make sure they don't get licked, but I don't encourage it either.
Licks to young kids (especially around the face), licks that have contact with skin lesions or mucous membranes (e.g. mouth, nose) or licks to people with compromised immune systems (including people that do not have a functioning spleen) are higher risk. Strep throat isn't a concern, but many other things are. There's a cost-benefit. If it's an important part of someone's bond with his/her animal, that's fine. Individuals just need to understand the risks, and be aware of when the risks are higher. Part of that is getting good advice, which can be a challenge on the internet.
Don't get me wrong. I'm all for pet therapy and animal visitation in hospitals - when it's done logically. I've been involved in research in the area, helped develop international guidelines and am chair of the medical advisory board of one of the largest pet therapy groups in the US. Animals can do great things in hospitals and we need to support good visitation programs. But that doesn't mean I check my brain at the door and think that all animals in all hospital situations are a good idea.
A colleague sent me a link to a Medscape News article entitled Woof! Does Fido Belong in the Hospital Delivery Room?
- My first thought was... not a chance. (My second, third and fourth thoughts were no better.)
The situation in the article isn't that clear cut though, since the English woman who wanted her dog in the delivery room had a trained therapy dog that helped her with an anxiety disorder. So, if this was truly a trained therapy dog (some people unfortunately make that claim just as an excuse to take their dog everywhere, and compromise people that truly need these animals), it would be justifiable since this is a service dog, not a companion, and we need to support access of service dogs.
However, it raises questions about whether this will open the door to requests for pets to join in the birthing process, now that we've moved from the era when dad paced outside the room to a time when half the family may be present, live-streaming the event to the internet and posting on Twitter.
What are some issues here?
A delivery room is a busy environment. Things can be nice and happy and relaxed. There can also be yelling (personal experience there), lots of activity and other things that might scare or upset the dog. I'm not worried about the dog's feelings here, but what a startled or upset dog might do (e.g jump, bark, bite, pee, try to run away).
Not all deliveries are smooth and things can go from good to bad quickly. The last thing that's needed is another distraction (e.g. the aforementioned dog jumping, growling, barking, peeing, etc.) when medical personnel are dealing with a life-threatening delivery complication.
A newborn is a high risk person for infectious diseases. Every dog is shedding multiple microorganisms that can cause disease. Usually, the risk is low. However, when you have a highly susceptible person (or persons, including the mother here to a lesser degree since post-partum infections are a concern), we don't want them exposed to pathogenic bacteria if we can avoid it. Yes, it's an ever-present risk in a hospital, but why add to the potential risks? It would seem illogical to have delivery personnel in full protective gear (e.g. gowns and gloves) with a dog potentially aerosolizing bacteria nearby through breathing, coughing, barking, shaking, and tail-wagging. People would also likely contaminate their hands often by touching the dog. Yes, medical staff can be to told to avoid contact with the animal and wash their hands, but we know from previous research that hand hygiene by medical personnel after animal contact is very (very!) uncommon.
Also, we know that a baby's first bacterial encounters have a major impact on its developing bacterial microbiome (that is, the composition of normal bacterial populations at various body sites, something that's important for good health and development). Babies born by C-section have much different microbiomes for a long period of time compared to those born by vaginal delivery. Do we really want to confuse the picture more by having some of the first bacteria encountered being Fido's bacterial flora? It's not going to make the baby start barking, but I'd rather the baby not be exposed to various bacteria from a dog seconds after it's born.
In my opinion, visitation is more important the longer the person is in hospital, the more lonely they are and the more upsetting or depressing the situation is. Delivery is typically a short-term, happy hospital stay. What's the real benefit here for your average dog owner?
Personal pets in any hospital situation is a controversial area. Unlike dogs that are part of proper visitation programs, these dogs tend not to have any health screening, behaviour screening or other type of assessment. There's also no handler training. You might say "well, the dog's just visiting its owner so that's not a big deal." However, the dog has to go from the parking lot to the room and back again. What are the odds that the dog's not going to encounter lots of other people in the process, let alone potentially distracting or scary situations. Do you want your elderly immunocompromised relative to ride (or be stuck in!) a hospital elevator with an aggressive or otherwise high risk dog? Or to have you child that just had surgery step on a pile of dog poop? There are clear screening, training and supervision criteria for hospital visitation dogs, and they are there for a reason.
Back to the article. Dr. Arthur Kaplan, the author, sums things up nicely:
"I think there are risks, and I think the risks are pretty significant. I am not sure that we should open the door to every barnyard creature we could think of to be present at birth, even when the mom-to-be says that she would like to have her pet there. But at the same time, I think there are arguments that, for some people, such as the woman in England who has a special relationship with her pet, or perhaps a woman who is blind, a case can be made."
In Canada (like most places), there's no semblance of a formal surveillance program for infectious diseases of companion animals. We're left with anecdotes and whatever short-term research projects we can put together to try to figure out what's happening in our companion animal populations. Not ideal, but better than nothing.
Over the past month or two, I've been hearing more rumblings about canine parvovirus infections in dogs in Ontario. Nothing too dramatic, just a spike in calls and emails about cases, mainly typical parvo cases (e.g. disease in young and un- or inadequately-vaccinated puppies, outbreaks in groups like shelters and breeding kennels) with some cases that seem more severe and some in dogs that seem to have appropriate vaccination history or in older dogs. It doesn't seem to be due to a focal outbreak, since these may be occurring in a few different regions in Ontario. This type of anecdotal information is far from definitive but enough to start asking questions.
I'm not the only one who's been hearing this. The Ontario Veterinary Medical Association has had enquiries and has been receiving more information from Ontario vets, so they have put out a press release indicating that something might be going on with regard to parvovirus in the province, and emphasizing the need for proper vaccination and preventive medical care for dogs.
So is something happening in Ontario? I'm still not sure. Sometimes situations like these are just because people are talking and we're hearing more about little clusters that go on all the time under the radar. However, this could be real and caused by a variety of factors such as decreasing vaccination rates, increased parvovirus circulation in some regions or a change in parvovirus strains.
The only way to truly figure out what's happening is to get more data. That's not an easy proposition since surveillance networks aren't established and there's no money to do any disease surveillance like this. However, Ontario veterinarians who are seeing parvo cases can feel free to provide more info and to send samples for typing.
I tend not to write about recalls but the recent, large and expanding pet treat recall has lead to a lot of questions that are worth discussing. At last report, treats manufactured by Kasel Associates Industries Inc from April 20-Sept 19, 2012 were potentially contaminated with Salmonella and recalled. Not surprisingly, most of the recalled treats are things like pig ears, bully sticks and jerky strips made from raw animal products. The impact on pets isn't clear beyond a vague statement about "a small number of complaints of illness in dogs who were exposed to the treats." Anyway, here are some common questions I've been hearing:
My dog ate a recalled treat, will it get sick? Maybe, but probably not. It's not clear how many treats were really contaminated, so it's quite possible that most products weren't contaminated. Furthermore, the dose of Salmonella that a dog ingests is important. Low-level contamination is less of a concern, particularly in otherwise healthy dogs. The strain of Salmonella itself also plays a role since some strains seem to cause more serious disease or cause disease at lower doses than others. I haven't seen much information about the strain (or strains) involved here.
If my dog gets sick, what will happen? That's highly variable. Salmonella can cause disease ranging from vague (e.g. a little depressed and decreased appetite) to classical intestinal disease (e.g. diarrhea +/- vomiting) to rare but severe systemic disease (e.g. sudden death, bloodstream infection with subsequent overwhelming body-wide infection or focal infection of different body sites like joints).
Should my dog be tested for Salmonella? Not if it's healthy. The main question is what would be done with the result. If positive, it wouldn't mean that anything needs to be done or even that disease is likely to occur. A negative isn't very helpful either since a single sample is far from 100% sensitive. The key point is that we treat disease, not culture results. If the dog looks healthy, it's not going to be treated, regardless of the culture result. You'd also need to have the isolate tested to see if it's the same as the strain in the recalled treats if you wanted to determine whether treats were the source, and that testing is not readily available.
Should my dog be treated with antibiotics? As you can guess from the paragraph above - no. There's no evidence that antibiotic treatment of an exposed dog or a healthy carrier reduces the risk of disease or shortens the shedding time. In fact, it might even make things worse by disrupting the normal protective intestinal bacterial population, which might make disease more likely or make it harder for the body to eliminate Salmonella. Treatment might also encourage development of antibiotic resistance, something we don't need any more of with Salmonella.
What can I do to reduce the risk of disease? Not much. If a dog has eaten a Salmonella-contaminated treat, there's not really anything that can be done after the fact beyond watching for signs of disease.
So... what should I do? Relax and watch. The odds of a problem are low. If a problem develops, odds are it will be mild. That's not to say that severe disease can't or won't happen, it's just that it's unlikely and there's nothing that you can do after exposure anyway. Identifying signs consistent with early disease (e.g. lethargy, decreased appetite, diarrhea) and getting prompt veterinary care should help reduce the risk of complications or serious disease.
A proposed Florida bill would require shelter operators to produce monthly and annual euthanasia reports. The reported goal of the effort is to "reduce euthanasia of unwanted animals." But how? The idea has various pros and cons.
Potential good points
More transparency: Euthanasia rates are often considered the "dirty secret" of the shelter world. In reality, it's not the shelters' fault that animals are being euthanized. It's society's fault because of overpopulation. Shelters should be reporting these numbers (and ensuring they are accurate), not as part of a "we kill fewer than you do" competition, but to highlight the challenges, increase public awareness and to work toward improving the shelter system.
More data: The more we understand the epidemiology of adoption, euthanasia, disease and other events in shelters, the better. Knowledge helps us figure out better ways to run things.
Potential bad points
Animal welfare: Will shelters resist euthanizing sick or injured animals that would otherwise be euthanized to keep their rates lower? If an animal is very sick, will there be the temptation to let it die rather than euthanize it, if deaths are not reportable but euthanasias are?
Overpopulation in shelters: If shelters try to avoid euthanising animals because the rates are reportable, there will be more animals in the shelters - likely more than they can actually handle. More animals in a shelter does not mean more adoptions. Overcrowding leads to many problems such as increased disease risk, deceased quality of care, decreased human contact and increased shelter operation costs.
Outbreak potential: Yet another issue related to overcrowding is when you cram in as many animals as possible (often using carriers and other temporary housing stashed anywhere there's spare space) and decrease the time you spend with each animal, you create great potential for a disease outbreak. The more animals are present, the more likely the outbreak will take hold and the harder it will be to control.
Needless transfers: Will shelters try to transfer animals that are unadoptable to areas where this law is not in effect, simply to be euthanized outside of the recording system? Beyond the humane aspects of putting the animal through the stress of a transfer for no real reason, shipping shelter animals is notoriously high risk for shipping diseases along with them.
Cherry-picking: This already happens with some shelters, but one way to keep euthanasia rates low is to refuse to admit animals that are not likely to be adopted. Turning them away doesn't help the animal or society (and may result in more animal suffering, among other things, if the animals are simply abandoned), but it keeps euthanasia numbers low.
Will this work?
Shelters don't euthanize for fun. They do it because there is a finite number of homes available and the number of animals coming into shelters (especially cats) is way beyond that. This bill will not magically create millions of new homes for shelter animals. So, how will it "reduce euthanasia of unwanted animals"?
A representative of a group working to reduce shelter euthanasias added "We do not believe that it is the conscious will of the people of the state of Florida to kill over 50% of the lost and homeless shelter pets each year." It's not their conscious will but what can/will they do about it? Euthanasia numbers might help spur interest in adopting from shelters, and if so, that would be great. But the fact is that if 50% of animals in shelters are being euthanized, it's because they don't have homes.
Probably a well-intentioned but poorly thought-out approach to the pet overpopulation problem.
It's not hard to find news articles about animal bites. That's because they are very common, sometimes incite controversy (e.g. to euthanize the offending animal or not) and occasionally cause severe injury or death.
Here's a sampling of some recent reports:
- The University of Arizona Medical Center is reporting a steady increase in dog bites, with an almost doubling of bite numbers between 2008 and 2012. Three-hundred and twenty-eight (328) people were admitted with bites last year, including both children and adults. Most were bitten on the hands and fingers, and most were bitten by their own dogs. There were no deaths reported in 2012, but there was one in 2011, a man that was bitten in the neck and arm by his own pit bull cross.
- Sixty-three dog bite deaths were reported in Mumbai, India, over the past 5 years, out of a total of at least 90 000 people who are bitten annually.
- A Stoney Creek, Ontario mother is lobbying to have her neighbour's two German shepherds euthanized after they attached her 10-year-old son. The dogs were on leashes and being held by a friend of the owner's 14-year-old son when "The dogs became startled" and the boy was bitten on the arm and face. The dogs' owner argues that only one dog was involved, but figuring that out will be next to impossible. This raises a few different issues. One is the fact that a child, and not even a child of the owner, was responsible for the control of two large dogs in a public place. Another is what lead to the bite. The owner accuses the boy of taunting the dogs in the past, but even if that were true, previous taunting (what did he do? accuse the dogs of having a chihuahua for a mother?) isn't an excuse for biting.
While we often focus on dog bites, pretty much any animal with a mouth can bite. Records from a New South Wales, Australia, ambulance service reveal some more unusual calls for help in response to animal interactions. These include:
- A call because of a "deep bite on the hand" with "serious bleeding" after a woman was bitten by a Guinea pig. They were also called for a Guinea pig bite to a 4-year-old boy. The fact that Guinea pigs would bite isn't surprising, but the fact that the bite would lead to an ambulance call is.
- A call for a cat bite that severed an unnamed artery of an 80-year-old man. Hopefully it was a small artery.
- While not a bite (although cattle can bite), ambulances were called when a cow hit a 83-year-old man in the stomach, lifting him 3 feet in the air, and when a water buffalo tossed another man.
- Other animal associated calls included incidents caused by critters including a blue-ringed octopus, a catfish (would love to have the story about that one) and a goanna (a type of Australian monitor lizard - had to look that one up).
- And (not surprisingly, for Australia) there were shark bites, including a spear fisher who was "nudged" by a grey nurse shark attracted to the fish he had caught, and a more serious attack by a bull shark that resulted in loss of a finger and a serious leg laceration.
- Snake and spider bites weren't even listed in the report for some reason.
Understanding why bites occur is important to preventing them, and it's different in different areas. In North America, where most dog bites are from family pets, better training of the dog and people in the household is critical. In a place like Mumbai, where there are tens of thousands of stray dogs living in close confines with people and where many bites are from strays, a different approach is needed. Bites from pocket pets usually result from improper handling or trying to break up a fight. Shark bites are also another story. Ultimately, a lot of prevention is common sense, which unfortunately is not always that common.
ProMed Mail's monthly US rabies update often contains some interesting cases, and the last one is no exception.
A llama in Georgia became aggressive, started biting itself and was spitting at one of its caretakers. A spitting llama certainly doesn't mean rabies (I have dodged enough llama spitballs to know that) but any sudden change in behaviour, especially with aggression, should raise some major red flags. Here, the llama was diagnosed as rabid and the person that was spat on is receiving post-exposure treatment.
A bobcat attacked a man and boy in Massachusetts, and not surprisingly, was diagnosed with rabies. In this case, the bobcat pounced on the man, bit his face, clawed his back and held him in something akin to a bear hug, before moving on to the man's nephew. Wild animals don't typically attack except under extenuating circumstances (e.g. being cornered, protecting offspring), so this type of event should be considered a rabies exposure until proven otherwise. The man shot the bobcat and it was confirmed as rabid.
In an all-too-common scenario, a family that took in a stray kitten ended up needing post-exposure treatment because the kitten was rabid. They found the sick kitten and tried to nurse it back to health, but it died the next day. Fortunately, animal control arranged for rabies testing, something that could have easily been overlooked if no one thought about rabies and just assumed the kitten was sick for some other reason. Two dogs in the household were also considered exposed, but fortunately had been properly vaccinated, so typical recommendations would be for a 45-day observation period versus 6 months strict quarantine or immediate euthanasia had they not been vaccinated.
In a similar scenario, two women are undergoing post-exposure treatment after being bitten by a stray kitten they were trying to catch. After they caught the kitten, they took it to a local Humane Society, where it was euthanized because of the bite. This ended up being an efficient approach, but more often there would be a 10 day observation period of an animal that had bitten someone, to see if it developed signs of rabies. If signs occurred the animal would be euthanized and tested for rabies, but if not then (theoretically) the animal would not have been shedding rabies virus at the time the bite occurred. Immediate euthanasia after a bite is not the typical recommendation, so I wonder whether the kitten was already showing some signs of disease. Otherwise, it wasn't a textbook approach to bite management but it ultimately resulted in the right outcome.
These cases have a few recurring themes:
- Changes in animal behaviour should lead to consideration of rabies.
- Be wary of stray animals. It's best to stay away from them. If you end up taking in a stray, if it gets sick and dies, ensure that it is tested for rabies.
- Vaccinate your pets because you never know when you'll encounter rabies.
1) Do you know what a bully stick actually is?
2) Do you know what's in it?
A recent study headed up by Dr. Lisa Freeman, published in this month's Canadian Veterinary Journal (Freeman et al., CVJ 2013;54:50-54), looked into this by asking people what they thought bully sticks were made of, and testing the treats for calorie count and bacterial contamination.
The answer to question 1 is: bully sticks are raw, dried bull penis (which explains the need for a cuter name).
- Only 44% of people surveyed knew that.
Also, bull penis is considered a by-product, yet 71% of people that fed bully sticks to their dogs said they avoid by-products in food.
- This just shows a lack of understanding about what by-products are and their nutritional value. Many people classified things that are prohibited from by-products as being by-products, such as hooves, horns, road kill and euthanized pets. By-products aren't always bad and can, in fact, have good nutritional value. Also, they can be environmentally friendly and ethical since they are often made from nutritionally valuable parts of the animal that might otherwise be thrown out, thereby providing food for pets without taking anything out of the human food supply chain.
"What's in it?" was approached from 2 standpoints:
Firstly, caloric content was assessed.
- Treats often get ignored when thinking about a pet's caloric intake, but calorie-dense treats can certainly contribute to obesity. Fifty percent of people surveyed underestimated the calorie counts of bully sticks. The average caloric density was 3 calories/gram, and given the variation in size of bully sticks, total calorie counts for a single stick ranged from 45-133 calories (9-22 calories/inch). So, yes, size matters.
Secondly (my bit part in this study), we looked at contamination by a select group of bacteria.
- Salmonella wasn't found, which was encouraging since high Salmonella contamination rates have previously been found in some treats (mainly pig ears), and contact with pet treats has been implicated in some outbreaks of salmonellosis in people. We found Clostridium difficile in 1 treat (4% overall). That doesn't worry me too much since it's increasingly clear that we encounter this bacterium regularly. With common sense and handwashing, it's probably of little risk, but in some people (e.g. elderly, people on antibiotics, people with compromised immune systems) it might be more of a concern. We also found methicillin-resistant Staphylococcus aureus (MRSA) in one sample. This was a "livestock-associated" MRSA strain that can cause infections in people, but the risk is unclear. Theoretically, it's a potential source of exposure. If someone got MRSA on their hands from the treat then touched their nose (where MRSA likes to live) or a skin lesion (where it can cause an infection), then it could potentially cause a problem. Overall, the risk is probably quite low, but it's another reason to wash your hands after handling treats.
None of this means dog owners need to avoid bully sticks. It does mean that you should pay attention to what you feed your pet, think about treats when considering your pet's caloric intake (especially if your dog is overweight), keep treats away from high risk people (e.g. don't use a bully stick as a teething toy) and wash your hands after handling dog treats (of any kind).
Photo: A variety of bully sticks (also known as pizzle treats) often fed to dogs as chew treats (photo credit: Gergely Vaas 2006 (click for source))
I seem to write about this bug a lot - disproportionately for a rare cause of infection - but it just keeps getting attention. Reading the title of a recent article "Woman loses legs, fingers to rare infection from dog bite," it was an easy guess that the infection was caused by Capnocytophaga canimorsus. That's the type of dramatic disease this bug can cause, and as hard as it is to say "lucky" about someone that loses digits or limbs, they are lucky since death rates are very high with this infection.
Capnocytophaga canimorsus is a strange little bacterium. It's found in the mouth of pretty much every dog, so people get exposed to it quite commonly, yet it rarely causes disease. However, when it does cause disease (often after an otherwise inconsequential bite), it's bad.
In the most recent report, a 48 year old woman received some minor bites breaking up a fight between two family dogs. The next night, she had a fever and was vomiting, and things went downhill from there (click here to read the full story). An unusual aspect of this case was that the woman didn't have any of the risk factors that are typically present in a person who gets a Capno infection, such as not having a spleen, being an alcoholic or having an immunosuppressive disease. It is unclear why this bug, which is normally quite innocuous to an otherwise healthy person, almost killed her.
An infectious disease physician at the hospital made a few recommendations:
"If a person experiences a dog or cat bite it’s reasonable to have it examined, especially if it’s swollen, painful or red."
- Pretty good advice. It's never a bad idea to get a bite examined, and in some situations, it should be mandatory (e.g. bites over the hands or face, bites to immunocompromised individuals).
"It’s important for the public to not only closely watch animal bites but also to make sure pets are current on their shots and that the owners are up-to-date on tetanus shots."
- Good general advice, but not really related to Capno.
"Dog owners should use caution when trying to break up a fight between animals, she said. Instead of reaching near a dog’s mouth, pull the tail, she advised."
- I'm not so sure about this one. Grabbing a tail of a fighting dog sounds like a good way to get bitten, although reaching near the mouth of a fighting dog would be just as bad or worse.
"Animals that are the source of such infections don’t need to be euthanized, Mondy said, but the dog that bit Sullins was put down for various reasons, including increasing aggressiveness and concerns about exposing babies in the family to the animal."
- Capnocytophaga should never be a reason to euthanize a dog since basically every dog is a carrier. It doesn't matter if there's a baby in the house or not. If the dog's dangerous because of its biting, that's a different story.
This article, along with various other recent reports, makes me ask a couple of questions:
Are Capnocytophaga canimorsus infections getting more common?
- I don't know. It's possible, as disease trends can change. It could also be that reporters are picking up these cases more often since they tend to be dramatic.
Are more low-risk people becoming infected?
- This one concerns me a bit. Traditionally, when I saw a report of Capnocytophaga in the literature or lay press, I could guarantee I'd eventually come across a statement about the person not having a spleen, or less commonly being an alcoholic or having some other immunocompromising problem. Again, it may just be my impression but I'm seeing more reports where a risk factor isn't apparent. It could be that an immunocompromising problem is there but is not known, but this report, along with some other recent news articles and a published case report, raise concern about the potential for this bug to cause disease in the absence of traditional risk factors.
This doesn't mean owners should fear their dogs, since it's still a very rare problem. However, it re-inforces the need to:
- Reduce the risk of bites through proper training (of both the dog and people who interact with it).
- Use prompt and proper first aid measures after any bite.
- Ensure that people who are at high risk for infection, particularly people without a spleen and those with compromised immune systems, always seek medical attention promptly after a bite.
A recent article in the Toronto Star detailed an "underground railroad" that helped get stray dogs out of Afghanistan and into homes in North America and the UK. While it's a nice heartwarming Christmas story, the Scrooge side of me starts asking questions about whether this is a good thing. To me, there are two different scenarios here:
One is the military person who befriends a stray dog while on deployment and wants to bring it home with him/her. I get that. A bond has developed between the specific person and dog, and I completely understand the rationale.
The other scenario, which is the one that raises my concerns, is when this type of action expands to groups that start "rescuing" random Afghan dogs that are then shipped back to Canada for adoption. This is an ongoing issue which has come up with dogs coming from a variety of countries under various circumstances (e.g. Hurricane Katrina dogs). This is very different than the first scenario above. While it's certainly great for most of the adopted dogs, I have a harder time justifying it. Here's why:
Cost: Thousands of dollars are spent on each dog. Is that a wise investment? Could these funds be used differently to help more animals?
Local shelters: It's not like we need to encourage immigration of stray dogs because our shelters are lacking in dogs. I don't know of any shelters that complain about a shortage of dogs for adoption. How can we justify spending thousands to import dogs when we already have an oversupply here? Does adoption of an imported dog (that cost thousands) result in euthanasia of an additional local dog, since there's a finite owner population?
Disease: Thanks to Canada's basically non-existent control over canine importation, this creates disease risks. If I wanted to do a study of Salmonella shedding by dogs in Afghanistan and have fecal samples from healthy dogs sent to me, I'd have to: A) Get an import permit from the Canadian Food Inspection Agency (CFIA); B) Have a facility inspection performed to confirm that my lab fulfills containment level 2 practices; and C) Get an import permit from the Public Health Agency of Canada. To import the whole dog, poop and all, I just need to produce a rabies vaccination certificate. If the dog is less than 3 months of age, I don't even need that. We've seen leishmaniasis in Ontario recently from dogs imported from Greece. There were major concerns about heartworm from "hurricane Katrina" dogs that were imported from Louisiana. A dog incubating rabies was imported by a US military person a few years ago. This is more than just a theoretical risk.
I'm not saying don't do this, I'm saying let's think about the costs and the benefits, and if it's to continue, let's make sure we have some logical and practical control measures in place.
Are the overall benefits worth the risks? Do people really want those dogs, or do they just want to say they own an Afghan rescue dog? What's the infectious pathogen burden in imported dogs? What diseases occur in imported dogs? Who's tracking these issues? (Answer: no one.) Should any regulations be put in place to reduce the risks?
Heartwarming story, but one that should at least raise some questions.
About 500 people have sent me this article over the past week, so I guess I should get around to making some comments. The article entitled "Using a dog’s superior olfactory sensitivity to identify Clostridium difficile in stools and patients: proof of principle study" (Bomers et al 2012) is in the Christmas edition of BMJ, an edition in which they typically publish something fun or light. The study describes the use of a dog trained to sniff out C. difficile, an important cause of diarrhea people, especially hospital patients. The premise is that dogs could be used as a rapid and cheap way to diagnose C. difficile infection, and therefore allow for earlier treatment and implementation of enhanced infection control measures.
There were 3 components of the study:
1) Detection of C. difficile on a culture plate
The dog was trained using culture plates containing C. difficile. That's how they have to start, but detecting C. diff on a culture plates is pretty easy. I can do that, and my nose is nowhere near as good as a dog's. Clostridium difficile has a very characteristic odour on a culture plate and odour is one of the methods that's commonly used to determine whether C. difficile might be present on the plate.
2) Detection of C. difficile in stool
For this, the researchers set the bar pretty low. A positive fecal sample was considered one that was culture-positive positive on a test to detect the C. diff toxins. We know toxin tests are pretty insensitive (they give a lot of false-negatives), which is why there's a major movement to replace them with molecular tests. By requiring the sample be positive on both culture and toxin test, it means that the samples had to have been quite positive to be considered (i.e. they didn't test the dog with "weaker" positive samples that may have had less C. diff and C. diff toxin in them). That weakens the results a bit, but they're still interesting.
They presented the dog with 50 positive and 50 negative samples. The dog gave a positive response to all 50 positive and a negative response to 47/50 negative samples.
3) Detection of C. difficile in patients
Here's where it gets more interesting and potentially more relevant, since the real value in a sniffer dog would be to detect C. diff directly from patients, as a rapid and cheap screening tool.
For this part, they enrolled 30 patients with C. difficile infection and 270 controls. One problem I have is that 94% of their controls were non-diarrheic. It raises questions about whether the dog is detecting C. difficile or just diarrhea, since the groups don't just differ by their C. diff status, as would be most appropriate for a control group. The more differences there are between the groups, the greater the potential that a difference other than the one of interest (i.e. C. diff status) is actually the thing that's being detected. There' a big difference between a dog that can detect C. difficile and a dog that just detects diarrhea.
Another issue is that some C. difficile strains don't produce toxins and are not able to cause disease, but they'd presumably be detected the in the same way based on odour, in contrast to tests that are based on detection of the bacterial toxin or genes that encode toxin production.
Anyway, the dog correctly identified 25/30 (83%) cases and 265 (98%) controls. Not as good as current molecular tests but pretty remarkable, nonetheless.
Overall, it's an interesting story and shows how good a dog's nose can be, how smart (some) dogs are, and how thinking outside the box can result in some interesting ideas. Though I don't think diagnostic testing companies have much to worry about at this time in terms of competition from sniffer dogs.
Cool concept. Fun paper. Not coming to a hospital near you in the near future, but not something to completely dismiss.
My youngest daughter Erin is in every-other-day kindergarten and goes to a child care centre on her non-school days. Overall, it's a great place - excellent people, great learning environment and she enjoys herself.
During the initial interview at the centre, what I do for a living came up and we got into a discussion about pets. The person doing the interview talked about how they had policies against bringing in animals because of potential risks and the difficulty in doing it right (e.g. right animals, right supervision, adequate hygiene, informed consent, knowing fears and allergies). In reality, their policies are not quite as strict as they say. I didn't get too worked up about the parent who was apparently bringing a young puppy in for visits. Erin's getting outside the high-risk window now (she turned five this year), she's not afraid or allergic, and she knows how to interact with dogs. Odds were pretty low that anything bad would happen, but it still wasn't right because I doubt there was much supervision or understanding of the dog's health status. As a puppy, he/she was at higher risk for shedding various infectious agents, as well as more likely to bite, scratch and poop on the floor. It's also a risk for high risk dogs owned by people who visit the daycare (e.g. if the puppy happened to be shedding parvovirus and the kids transferred it on their hands or clothes to puppies in their households, like our puppy Merlin). Anyway, like I said, not a great idea but nothing to get too worked up about.
The next issue was a bigger deal. As I was picking Erin up yesterday I saw a bulletin board display that highlighted a recent trip to a pet store by the younger kids. On it was (predictably) pictures of these young kids handling reptiles, including turtles. As I've said before, reptiles can be good pets. But, they are clearly high risk pets and high risk people, including kids less than five years of age, shouldn't have contact with them.
I assume the parents of these kids had to sign a consent form. It probably said something like:
"We will be visiting ___ Pet Store to see and learn about animals."
It probably didn't say....
"We will be visiting ___ Pet Store, where your child may be handling high risk animals."
It definitely didn't say...
"We will be visiting ___ Pet Store, where, contrary to recommendations from the CDC as well as virtually every other public health organization that has put pen to paper, your child will be handling animals that have a high likelihood of being covered in Salmonella. Someone might try to ensure that she washes his/her hands after... maybe... We are optimistic that your child will not join the tens of thousands of people that develop reptile-associated salmonellosis every year and we really hope he/she isn't one of the handful of small children who die from it. Good luck! Please sign here."
There's a difference between a consent form and informed consent.
There's an educational value of interacting with animals and there are animal encounters where the risk exceeds the benefits.
I have no doubt that the field trip was arranged with the best of intentions; however, this shows that there is still a need for education of child care providers about pets and zoonoses. The pet store needs to be considered too, since they probably do this regularly. They should know better, and every pet store employee should know basic information about zoonotic disease risks and preventive measures associated with the pets they sell. Pet store visits aren't inherently bad, but they're "pet stores," not "petting stores," and it should be a look-but-don't-touch interaction.
People sometimes accuse me of being a kill-joy, but they miss the point. My girls would have more fun if we let them roll around in the van while driving rather than restraining them in car seats and booster seats (as often happened when I was growing up). I want my kids to have fun, but I'm not going to let them do things that are that dangerous. I want my kids to have pets and interact with animals, but I want it to be as safe as possible. There will always be a risk of infection or injury, and as someone who's informed and as their parent, I can define the degree of risk that I am willing to accept for them. Child care agencies have to look out for the welfare of the children they supervise. Zoonotic disease exposure prevention is part of that. It's not a matter of taking the fun out of life, it's making sure that we provide safe fun.
Life with Merlin has been busy but going pretty well. There's been no pee on the floor in the past 48 hours so we're making progress. Speaking of pee (which, sadly, I seem to do a lot), we need to decide about leptospirosis vaccination for Merlin.
A good preventive medicine program is important for every pet. There's no "one size fits all" version - the program needs to be tailored for every region and pet/owner combination. We have Merlin's deworming covered. I gave him a booster vaccine the other day, which covers distemper, parvo and a couple of respiratory viruses (adenovirus type 2 and parainfluenza). Rabies vaccination will be coming soon, when he's a bit older (at least 3 months). Now that we have the "core" components covered, we need to think about the elective aspects. One of those is vaccination against leptospirosis.
When thinking about vaccination, it's a cost-benefit decision. The costs and benefits can be hard to accurately assess, but a few basic questions are key: Is there a risk of exposure? Is the disease of concern? Is there a safe and effective vaccine?
Is there a risk of exposure?
Leptospirosis, a potentially life-threatening infection caused by different types of Leptospira bacteria, has been called a "re-emerging" disease in many parts of North America since rates of infection have increased over the last 20 or so years.
Leptospirosis certainly occurs in dogs around here. We don't see a lot of cases but it's far from rare and it can be nasty.
Wildlife are the main reservoir. Infected wildlife shed the bacterium in their urine, and urine-contaminated water and wet areas are the main sources of infection. Raccoons are the biggest concern around here, and there is certainly no shortage of raccoons around my house (including in the garage sometimes). Since Merlin is a Labrador, he's bound to spend a lot of time swimming in ponds and wallowing around in wet areas on our property... prime sites to be contaminated by pee from infected wildlife. So, there's a reasonable chance that he'll be exposed.
Is the disease of concern?
There's no doubt here. While it's uncommon, it can be nasty. Life-threatening infections can occur and kidney failure is a major problem. Treatment of lepto can be difficult and expensive.
Is there a safe and effective vaccine?
Lepto vaccines have had a bad rap. Older vaccines weren't very effective (often not protecting against the strains that are of concern) and were associated with a high rate of adverse reactions. Those former concerns have persisted in some people despite the fact that there's a new generation of vaccines that are much more effective and safer. The new vaccines are better designed, better tested and cover a broader range of strains. There's quality research indicating that they work. Like any vaccine, they're not 100% effective but they are quite good overall.
Information about adverse reactions is harder to get. Adverse event reporting is sporadic at best, but the available information doesn't indicate that these vaccines cause a greater incidence of adverse reactions than any other vaccine. Any given vaccine can cause a problem in any given dog, but the overall risk is low.
So, don't tell Merlin but another set of vaccines is in his future.
As I mentioned the other day, I took a fecal samples from Merlin, our new puppy, to see what I'd find and show how you have to be careful with interpreting diagnostic test results. In addition to an unconcerning (for me) amount of clostridial bacteria in a fecal smear, Campylobacter was also isolated on bacterial culture. It's important to note that Merlin has not developed any diarrhea this whole time.
Interpreting Campylobacter results can be tough. This bacterium is an important cause of diarrhea in dogs and people, and contact with puppies is a known risk factor for human infection. So, should I be concerned for Merlin or the rest of the family?
The answer in this situation is no.
Why? All Campylobacter are not created alike. There are two main groups of Campylobacter: catalase-positive and catalase-negative. Catalase-positive species, most notably C. jejuni and C. coli, are the main concern in both animals and people. Catalase-negative species tend to be of little to no concern and are very common. We isolated a catalase-negative species from Merlin, one that's not been associated with disease in dogs or people.
Understanding test results and ensuring that testing makes sense is critical. If a lab just reports "Campylobacter positive" as is the case with some (especially labs that just offer PCR (molecular) testing), I wouldn't know what to think of the result. I need to know the species, or at least catalase-positive vs catalase-negative, to put the results into context and come up with a plan. In this case, the plan is to do nothing (or at least nothing we weren't doing already).
More information about Campylobacter in pets is available on the Worms & Germs Resources page.
Life with Merlin is going fairly well and the house training has been surprisingly good (so far). He was straining a bit to poop yesterday so I was wondering if diarrhea was on the way. Diarrhea wouldn't be too surprising since he's had a pretty good shock to his system with a big lifestyle change and a new diet (gradually transitioned, but a change nonetheless). But, so far, so good.
This morning, I collected a fecal sample from him. I'm getting it checked for parasites, as I mentioned the other day. I also did fecal cytology, out of curiosity and because I can do it easily and quickly in my lab. Fecal cytology is a controversial area for diagnosis of bacterial intestinal disease in dogs. Some people use it to diagnose "clostridial" disease and certain other problems. A common statement is that seeing more than 5 clostridial organisms per high power field under the microscope is indicative of a problem. However, a recent American College of Veterinary Internal Medicine consensus statement on the diagnosis of bacterial enteropathogens basically said that this "rule" is pretty useless (disclaimer: I was one of the authors). Yet, some people continue to use it.
Why do I think it's useless?
- There's no evidence indicating that it's accurate. All of the (very few) studies that have looked at this test in dogs have found it to have no usefulness for diagnosis.
- On a fecal smear, you look at a couple of hundred bacteria. That's a miniscule percentage of the trillions of bacterial present in the animal, and there's no assurance that bacteria are equally distributed, so there's no way to tell if what you see is truly representative of the entire bacterial population (it probably isn't).
- There are a few hundred species of Clostridium. Only a few species are known to cause disease. Many of the others are probably important components of the intestinal bacterial population that are important for gut health, so they should be there.
- You can't identify a Clostridium species by looking at it under a microscope. It looks like a purple rod when using a typical Gram stain. The "bad" clostridia look no different than the "good" clostridia. Also, there are many other bacteria that have the same appearance. So, finding lots of "clostridia-like" organisms is incredibly non-specific - it really doesn't tell you much of anything.
Back to Merlin's poop sample: When I looked under the microscope, I could see lots of clostridia-like organisms. Certainly, there were more than 5 per high power field. Yet, he's bright, alert, eating well, and has formed stool. Yes, something could be brewing but I don't see any real sign of that. Some people would treat him with an antibiotic such as metronidazole based on this cytology finding alone. I think that's a bad idea because he's not sick, I doubt he's getting sick, I have no evidence that he has an intestinal bacterial disruption that needs to be treated and the last thing i want to do is mess up his developing intestinal bacterial population with an antibiotic. That's just asking for trouble.
So, no antibiotics for Merlin. Dewormer... that's another story.
The new puppy, now named Merlin, is keeping things busy around here. (Note to self: avoid getting a new puppy during miserable weather. Standing in pouring, driving rain at 4 AM is not fun. Okay, enough whining.)
Yesterday, I wrote about the new puppy's deworming plan. One thing I forgot to mention was the rest of the "herd." By that, I mean Meg, our 11-year-old Lab. Herd health gets a lot of attention in food animals and to a lesser degree in horses, but many concepts remain important for pets. Specifically, when you introduce a new member into the herd, you might change disease risks or required preventive measures for other members of the herd.
Meg lives a pretty cat-like existence. She sleeps, eats, walks far enough to go outside to pee and, well, that's about it. As an older dog who has very rare contact with other dogs, her risk of exposure to many microorganisms, such as parasites, is limited. However, since we brought a new little furry vector into the house, Meg might be exposed to some things that haven't been much of a concern in the past. Her habit of eating whatever she can find (including poop), increases that risk further. So, what's the herd health plan?
It's not too detailed, actually.
- One thing is making sure that we deworm Meg and we don't just focus on the puppy. She might be exposed to anything the puppy is/was shedding. We're usually pretty lax on deworming her in the winter months, but she'll get a couple of doses of dewormer alongside the puppy.
- Poop removal. Since Meg's a notorious poop-eater, we'll want to remove Merlin's waste promptly. That's pretty straightforward. If she can't find it, she can't eat it. It's also important to make sure that old feces aren't left around, because some parasites require time in the environment to become infectious, so regular feces removal prevents accumulation of infective forms of some. The current temperature is at the lower limit of where Toxocara eggs are able to develop into infectious larvae, and the risk will probably be pretty minimal as the temperature drops over the next few days, but it's not hard to make sure the yard gets cleaned up.
- If we find something in the puppy, then we'll have to consider whether Meg might be exposed or at risk too, and decide whether she needs to be tested or treated.
The other aspect of the herd is the non-canine component of the household (i.e. the kids). The key points for that, in terms of zoonotic parasites, are cleaning up feces from the yard, avoiding fecal contact, hand washing, treating the dogs appropriately to reduce parasite shedding and other basic feces-avoidance measures.
Hide the kids’ toys, tune up the carpet cleaner, get ready for some sleep deprivation… there’s a new dog in the house. Last night, the yet-to-be-named ("he who shall not be named" having been rejected by Heather) little yellow critter arrived. Meg (the existing dog) seems relatively content, or at least resigned. The cat... not so much, but he's already established who's the boss.
So, while I'm momentarily not trying to convince the puppy to pee outside, I’ll take this opportunity to hopefully practice what I preach and describe what we’re doing for things like vaccination, deworming and other infectious disease-related topics.
To start things off: What’s the deworming plan?
- Roundworms (Toxocara canis) are the main concern in puppies. It’s generally a good idea to assume that a young puppy has roundworms, regardless of from where it came and how well cared for it was.
- Canadian parasite treatment guidelines are to treat puppies with a drug that will kill Toxocara worms at 2, 4, 6 and 8 weeks of age, then monthly until 6 months of age. Our little guy is 9 weeks old and has already been treated a couple of times for roundworms, plus he's had one treatment for coccidia (a different parasite that was found on a recent fecal exam). He’ll get another dose of pyrantel pamoate in the next day or two, then monthly until he’s 6 months old. (If someone gets a puppy and it hasn’t been treated like this or its vaccination history isn’t known, it is recommended to give 3 treatments 2 weeks apart, then monthly until 6 months).
- A fecal exam will be done on the puppy in the near future. It’s not an emergency since it won’t impact what I do at the moment in terms of treatment, but it’s good to see if there are any parasites that aren’t killed by the chosen dewormer (e.g. tapeworms) and to detect resistant parasites (i.e. Toxocara eggs still found in feces after appropriate treatment).
- No flea treatment now since he doesn’t have any evidence of a flea infestation and it’s not very likely he’ll be exposed to fleas before the spring based on the current climate where we are.
- No heartworm treatment until the spring either. The Canadian Parasitology Expert Panel (CPEP) recommentaion is for dogs to receive monthly heartworm preventive treatments beginning at a maximum of two months of age. So, I’m not really following that one, but given the time of year, the low prevalence of heartworm in the area he's from and the fact that the puppy wouldn’t have had too much risk of mosquito exposure because of its age and indoor housing, the risk of heartworm exposure this season is very low.
More updates to come, and hopefully not too many descriptions of how to clean puppy feces off of various surfaces.
I’m at the International Conference on Equine Infectious Diseases in Lexington, Kentucky at the moment, and will try to write about some of the highlights. One interesting discussion yesterday was about canine and equine influenza. It’s well established that canine flu (A/H3N8) originated in horses and subsequently became established in dogs. Canine flu virus is closely related to, but different from, its equine flu virus parent. That raises questions about whether canine flu virus could be transmitted back to horses. The question has significant implications for what should be done with dogs that might have canine flu that may have contact with horses, and for canine-horse contact in general, especially with performance horses.
A study by Yamanaka et al. (Acta Vet Scand 2012) looked at dog-horse infectivity of canine flu by putting infected dogs in stalls with healthy horses for 15 days. All dogs were sick and shedding canine influenza virus, but none of the horses got sick, shed the virus or mounted an antibody response. This study only involved three horse-dog pairs, so we have to be careful that we don’t go too far with the conclusions, but it suggests that while canine flu started off as horse flu, it has changed enough that infected dogs aren’t much of a risk to horses.
But... (yes, there’s usually a "but" with infectious diseases) dogs are susceptible to "normal" equine influenza. It’s uncommon, but dogs can be directly infected from horses with the classical equine H3H8 flu virus. In such a situation, dogs might pose a risk to horses because they are carrying the equine virus, not the adapted canine version.
- If a dog has influenza that is known to be non-horse associated (i.e. typical canine flu) then there’s probably little concern for horses.
- If a dog has influenza and there’s no clear dog link (or there’s a link with infected horses), it’s reasonable to assume that the dog could transmit the virus to horses.
However, why take the chance? It seems logical to ban any dog with a suspected respiratory infection from horse barns. It also makes sense to ban dogs from barns with equine flu cases. It’s an easy, cheap, minimally disruptive and potentially useful flu control measure that might help reduce transmission of this important virus in both directions.
People sometimes get freaked out by the concept that they have approximately 10-times as many bacterial cells on them as all their own body cells combined.
- Yes, our cells are a minority in our own bodies, and amongst the trillions of bacteria we carry are many that could kill us given the opportunity.
Yet, we have somehow managed to survive, both individually and as a species. So, keeping things in perspective is important and, in reality, we need much of that bacterial population to keep us healthy.
Just like every person is carrying many bacteria on any given day that can cause illness or infection, every animal is carrying many different microorganisms that can infect a person. While infections from pets do happen, they are uncommon - we're not seeing dog owners dropping like flies on the street, which is a testament to our immune system and other body defenses and barriers (e.g. intact skin).
So, when studies come out describing various bugs at various sites in various animals, you have to put them into context. It's not that the studies are bad (my lab does a lot of work trying to define the complex bacterial populations of sites like the intestinal tract, oral cavity, respiratory tract and skin), it's that we need to think about what the results really mean and avoid sensational headlines in the press.
A recent paper in the Archives of Oral Biology (Yamasaki et al. 2012) is an example of this. The study looked at mouth bacteria in dogs and their owners. They used molecular testing developed for human oral samples and focused on bugs that have been implicated in dental disease - not the range of bugs that are more often associated with zoonotic infection. Not surprisingly, they found lots of different bacteria in the mouths of the dogs, including some bacterial species that were present in both dogs and their owners. No methods were used to type the bacteria to see whether the strains found in dogs and people were the same or whether dogs and people just normally have those bugs present, independently, in their mouths. However, we know that transmission of certain bacterial between people and their pets is a relatively common event, and it wouldn't be surprising if the same applies for oral bacteria, through direct contact (e.g. kissing/licking) or through indirect contact (e.g. a person touching a dog's face then his/her own face).
So, this was an interesting study... nothing earth-shattering but the first side-by-side comparison of oral microflora in people and dogs, and it provided some useful information for future research. The authors rightly discuss the limitations and things that need to be done to further investigate this, such as looking at strains and evaluating the bacterial population in relation to types of contact that people and dogs have (e.g. do certain activities increase the likelihood that people and pets share oral bacteria). They conclude by writing "In summary, we found that the distribution of periodontopathic bacterial species in dogs and their owners is diverse, though several species including P. gulae may be transmitted during close daily contact. Therefore, our findings could be significant in understanding the relationship between the oral health of humans and their companion animals"
Yet, headlines like "New study warns against kissing your dog" don't really reflect the true content... not uncommon but unfortunate.
I get asked about dogs licking a lot. My general line is that I don't particularly like to be licked but for the average healthy person, I don't get worked up about it. My kid were playing with puppies yesterday and were getting licked. I didn't fire up the power washer to hose them down after. If I had an infant, an immunocompromised child or some other high risk person it would be a different story. Licking around the ears is something I like to see avoided because of some links between this activity and certain ear infections in kids, but overall it's a relatively low risk situation that some people enjoy.
When I give talks about methicillin-resistant staphylococci, I almost invariable get into a discussion of the risks of methicillin-resistant S. pseudintermedius (MRSP) in people. This bug is becoming increasingly common in dogs and because it's so resistant to antibiotics, there's concern about whether it can be transmitted to people.
My usual answer is that there is a low risk of MRSP infection in people, but not no risk. MRSP is no more likely to cause an infection in a person compared to it's antibiotic-susceptible counterpart, regular S. pseudintermedius (the resistant version is just harder to treat). Most dogs carry susceptible S. pseudintermedius in their mouths, nose, skin, ears and/or intestinal tracts, so people in contact with dogs are very commonly exposed. Yet, human infections seem to be quite rare. There are periodic reports in the medical literature about S. pseudintermedius infections in people, but they tend to be single case reports, and when someone can publish a report of a single infection in person, you know it's pretty uncommon (since if it was common, no journal would be interested).
That's my long-winded way of introducing a recent case report in the Journal of Clinical Microbiology (Hatch et al. 2012). The patient in the report was an elderly man with underlying disease, so someone who was at high risk of infection from bugs that don't often affect otherwise healthy people. He had skin lesions, sore joints and a bloodstream infection, and "S. intermedius" (I'll get to the name issue later) was isolated from his blood. Fortunately, he was successfully treated. He owned a dog and that was (reasonably) considered to be the source of the bacterium, but no testing was done to look into that. So, from a disease standpoint, it's not really a surprising case - just another in a series of very rare infections that have happened.
The other issue here is the fact that the authors (along with the diagnostic lab, the journal's reviewers and the editor) are behind the times and don't realize that it's virtually guaranteed that this person didn't have a S. intermedius infection. Rather, it was presumably S. pseudintermedius, or perhaps another similar staphylococcus. It wouldn't have much of an impact on this particular case, although not knowing the species probably also indicates the lab doesn't know that there are different breakpoints to determine if the bug is methicllin-resistant, and there's the potential they would miss methcillin-resistant S. pseudintermedius and use an inappropriate and ineffective treatment (fortunately that didn't happen here).
I've had a few (well... more than a few) calls about potential risks to animals from the large Canadian E. coli O157 beef recall. The main concern is for dogs that are fed potentially contaminated raw meat that has been recalled, but there is also potential for exposure through cross-contamination if people in the household consumed any suspect products, and through dogs getting into garbage containing meat packaging. The other issue is whether dogs and cats can become exposed, start shedding the bacterium in their feces and subsequently infect people. Contamination of a pet's food bowl leading to human exposure is also a potential concern, especially considering the fact that as few as 10 of these E. coli bacteria can cause infection in people.
Overall, these risks are quite low. The contaminated meat is primarily a human concern. The role of E. coli O157 in disease in dogs is pretty unclear, but there's no evidence it's a significant problem. Experimentally, disease can be induced in dogs fed relatively high numbers of E. coli O157, but natural disease seems to be rare (including in dogs on beef farms where exposure is probably relatively common). I think it's reasonable to suspect that this strain of E. coli can cause disease in dogs, but it doesn't happen very often. We also don't recognize hemolytic/uremic syndrome (HUS) in dogs (the severe form of E. coli O157 infection that can cause kidney disease in people).
The risk to people from recalled meat is real. The risk to people from pets is pretty remote. Studies have not identified pet contact as a risk factor for human E. coli O157 infection. Dogs have been implicated as vectors in a limited number of specific household situations, albeit with rather weak evidence and only when focused on people and animals on beef farms.
Overall, the risks to pets and from pets are pretty limited. The main concern with the recalled meat is human disease. That being said, I wouldn't recommend people feed recalled meat to animals instead of disposing of it, since there is a possible though slight risk to both humans and animals.
A Wyoming (USA) dog has died of necrotizing fasciitis (more popularly and dramatically known as "flesh-eating disease"). This isn't unheard of in dogs, but it's a pretty rare disease. The six-year-old Great Dane's infection apparently raised some concern because of the diagnosis of necrotizing fasciitis in three people in the area. However, there is no known connection between the dog and the human cases.
While not anything new, the case is noteworthy for a few reasons, not the least of which is the high mortality rate associated with this disease. A few different types of bacteria can cause "flesh-eating disease," but streptococci are most common. The news reports say the dog had Group A strep, which is quite surprising and raises a lot of questions, such as:
- Was it really Group A strep? Most of these infections in dogs are caused by a related bug, Streptococcus canis, which is a Group G strep. Group A strep is essentially unheard of in dogs and I have to wonder whether the bacterium was misidentified by the lab or the reporting is inaccurate.
- If it actually was Group A strep, what's the public health concern? Group A strep is a common bug in people (the one that causes strep throat) but invasive infections like necrotizing fasciitis are a much bigger concern, and potential dog-human transmission would have to be considered.
- If this was Group A strep, are public health authorities taking the same steps was they would in response to finding Group A strep necrotizing fasciitis in a human in the household (such as the Public Health Agency of Canada's Guidelines for the Prevention and Control of Invasive Group A Streptococcal Disease?) This would make sense to me.
- If this was really Group G strep (the most likely scenario), did the dog receive a fluoroquinolone antibiotic before the infection set in? It doesn't sound like that was the case from the article, but knowing for sure would be interesting. Most cases of Group G strep necrotizing fasciitis that we see are associated with enrofloxacin treatment of an initially mild infection, since this drug can induce increased virulence in Group G strep.
Regardless of whether it was Group A or Group G strep, it's an unfortunate situation for the dog and the family, but people shouldn't be too concerned because this is a very rare, sporadic disease in dogs and one that has not been linked to any risk to other species.
.Dirofilaria immitis is the parasite that causes heartworm in dogs (and rarely cats). This mosquito-borne parasite can cause serious disease in dogs, and a lot of effort is spent trying to prevent heartworm infection. It can also cause disease in people who are bitten by a mosquito that has fed on an infected dog, but human infections are quite rare and of limited health risk. The main concern with regard to human infection is that it can create a small mass in the lungs. The mass itself isn’t usually a problem, but if it gets seen on an x-ray, it may appear very similar to a lung tumour, potentially leading to the use of more invasive diagnostic techniques (e.g. lung biopsy) to rule out cancer.
Dirofilaria immitis is not the only species of Dirofiliria. In fact, there are mulitple different Dirofilaria species with different hosts, some of which can also rarely infect people.
When it comes to dogs, D. immitis is the main concern, but dogs are also the host of Dirofilaria repens, which is most common in Mediterranean countries, eastern Europe and sub-Saharan Africa. Now, there’s a new one to add to the list, based on a paper in the Journal of Clinical Microbiology (To et al. 2012) that describes a novel Dirofilaria species in Hong Kong. Interestingly, it was found first by identifying disease in people.
Three human cases were identified in Hong Kong over a 10 month period in 2011-2012. When the researchers recovered the parasite from these individuals, they determined that, while it looked like other Dirofilaria, it was genetically different from any known species. They have tentatively named it «Candidatus Dirofilaria hongkongensis» (not very original but descriptive).
They then tested blood samples from 200 dogs and 100 cats, and found a parasite in six dogs that was identical to the new Dirofilaria from the human patients. They also tested the dogs with a commonly used commercial heartworm test that detects D. immitis and they were all negative, except for one dog that was actually infected with both the new species and D. immitis.
This is an interesting report and shows the need to be aware of potentially emerging issues. Some important questions need to be answered:
- What’s the risk to people? Obviously it can cause disease, since the three people in this report were actually sick. However, is this a very rare condition or something that may be more common? Is it something that’s been around for a long time and not diagnosed or is it really new?
- How do people get infected? They presumably get it from being bitten by an infected mosquito (as for other Dirofilaria) but how does the mosquito get infected? Are dogs the main source, one of many sources or are they inconsequetial?
- Does this new Dirofilaria cause disease in dogs? The six positive dogs were healthy, at least at the time of testing. Heartworm caused by D. immitis is a gradually progressive disease, meaning the signs become worse over time, so the fact that these dogs were clinically normal doesn’t mean there’s no risk, as they could start showing signs later on.
- What is the risk outside of Hong Kong? It’s hard to say because we know so little about this parasite, but it’s probably limited, at least at this point in time.
If you ask people about tapeworms, they typically think about the "ick" factor of having a large worm in their gut, but they probably don't get too concerned. However, some types of tapeworm infection can be serious health problems in humans and animals. One of the worst is infection by the tapeworm species Echinococcus multilocularis. A couple of recent reports about E. multilocularis in Canada have received a lot of attention.
With Echinococcus, the problem isn't the worm living in the intestine. Adult worms live in the intestinal tract of only "definitive hosts," which are primarily foxes and coyotes in North America. The worms aren't necessarily a problem for these animals, but they can pass large numbers of tapeworm eggs in their stool. The parasite's normal life cycle continues when small animals (e.g. rodents like mice and voles) swallow a tapeworm egg. The parasite then develops into a cyst in the animal's body, and if/when the little critter is eaten by a fox or coyote, the cyst gets eaten too and the fox/coyote develops a new adult tapeworm in the intestinal tract.
When it comes to people (and some other domestic species), the problem is what happens when they ingest tapeworm eggs. Like in rodents, the eggs hatch and the immature parasites migrate through the intestinal wall, and can then spread to virtually any place in the body. They can then develop into large cysts that, over a long period of time, result in serious disease. Large cysts and/or cysts in critical areas (e.g. the brain) can be devastating. Treatment is difficult, prolonged and expensive, and death rates are high.
Dogs are a bit of an oddity in this cycle, since they can carry adult tapeworms (not surprising, since they are similar to foxes and coyotes) but they can also get these large tissue cysts. From public health and infection control standpoints, dogs shedding Echinococcus eggs are the main concern, but cysts are potentially devastating in the rare dog that develops one, just as they are in people.
Recent concerns revolve around two papers, one that described a dog from British Columbia with Echinococcus cysts (Jenkins et al. Emerging Infectious Diseases 2012) and a study that identified E. multilocularis eggs in feces from 23/91 (25%) urban coyotes in Alberta (Catalano et al. Emerging Infectious Diseases 2012).
What's the risk in Canada?
It's low. Actually it's very low, and there have been only a handful of cases diagnosed even in people in North America. But with a serious disease like this, you can't ignore it. If Echinococcus is spreading in coyotes and foxes, it creates the potential for exposure of other species (including humans). The risk gets higher as coyotes and foxes get closer and closer to people and dogs, as is happening in some areas because of urban sprawl. The more coyotes that are around and the closer they are to human populations, the greater the chance that a person or dog will inadvertently ingest a tapeworm egg from coyote feces. Dog parks may be of particular concern because of the high traffic through them and the potential for them to be a big mixing site between wildlife, pets and humans.
There shouldn't be any panic because of this, as it still remains an extremely rare disease. But, it's not much consolation that it's a rare disease if you're the one with a big Echinococcus cyst in the brain. So, while the risk is low, we don't really know (yet) whether it's changing, and it's worth using some basic practices to reduce the risk. These include:
- The standard: Don't eat poop. Pretty straightforward but easier said than done, in many respects, since fecal contamination of the environment is pretty common. Avoiding inadvertent ingestion of feces can be done through proper handling of dog and wildlife feces and attention to handwashing.
- Controlling rodents and preventing pets from catching and eating rodents.
- Preventing dogs from eating wildlife feces.
- Routine tapeworm deworming should kill Echinococcus and if a dog is at particularly high risk, more regular testing and treatment for tapeworms may be indicated. Not many dogs fit into that category at the moment, though.
Image: Echinococcus multilocularis isolated from a fox in Hungary. Unlike the very long tapeworms of the Taenia genus, which are most commonly found in dogs and cats, Echinococcus tapeworms are quite small (the bar in the picture is 0.5 mm), but the eggs shed in the feces of animals with an intestinal infection (involving mature adult worms) are virtually identical to those of Taenia spp. (click image for source).
The annual US rabies surveillance report has been published in the latest edition of the Journal of the American Veterinary Medical Association (Blanton et al 2012). There's not really anything earth-shattering in it, but it's a good overview of the rabies diagnoses in the US from 2011. As always, it only provides a peek into rabies in wildlife (since only a small percentage of wildlife with rabies get diagnosed and reported) but numbers and trends in domestic animals, along with general wildlife data, provide useful information about the state of this virus in the US. Among the highlights:
- Rabies was diagnosed is 6031 animals and 6 people, from 49 states and Puerto Rico (Hawaii remains rabies-free). This is a 2% drop in animal cases from 2010, but I don't put much stock in that because the numbers are weighted towards wlidlife cases, and it's hard to have confidence in year-to-year numbers of rabid wild animals (because it's so dependent on what actually gets tested).
- The main wildlife species that are involved in maintaining the rabies virus in the US (reservoir species) continue to be raccoons, bats, skunks and foxes on the mainland, and mongooses in Puerto Rico. The relative importance of these species varies between regions.
- Raccoons were the most commonly affected species, accounting for 33% of all rabid animals reported. Other leading species were skunks (27%), bats (23%) and foxes (7%). Less common species included coyotes, bobcats, javelinas, deer, otters, mongooses, wolf hybrids, groundhogs and beavers.
- Cats were the leading domestic animal, with 303 diagnosed cases. Dogs came in next with 70, followed by cattle (65), horses (44), and goats and sheep (12). There were also single cases in a domestic bison and an alpaca.
- The six human cases represent the highest annual number of cases since 1994, if you exclude 2004 where four cases were associated with transplantation of organs from a single infected person. In a review of the 24 domestically-acquired human cases from 2002-2011, 88% were linked to bats.
- Three of the six 2011 human cases were acquired outside of the US; one each from Haiti, Afghanistan and Brazil - and all from dogs.
- Two of the three domestically-acquired cases were associated with bat contact. The source of the remaining case, an eight-year-old girl, is unknown, but contact with cats from a feral colony near the girl's school is a possibility.
- 5/6 people with rabies died. That's actually an impressive survival rate, since any survival is still a very noteworthy event when it comes to rabies. The survivor was the eight-year-old girl, and she apparently has suffered no longterm cognitive impairment.
Interestingly, we get a good synopsis of Canadian rabies data in this report too:
- 115 rabid animals were identified, with 92% being wild animals.
- There were three rabid livestock (two of which were horses) and six dogs and cats.
- No rabid raccoons were identified, continuing a trend started in 2009.
And regarding rabies in Mexico:
- 148 rabid animals were identified, mainly cattle (82%).
- Rabies was diagnosed in 20 dogs, with evidence that the canine rabies virus variant (which has been eliminated from Canada and the US) is circulating in some regions.
- There were three humans cases: two acquired from vampire bats and one from a skunk.
The Guelph Humane Society has re-opened after a temporary closure to manage a potential ringworm outbreak. The shelter took an aggressive, proactive approach to the issue, including testing and treatment of all animals and thorough disinfection of the facility.
Looking back on a proactive outbreak response like this one, it's always hard to say if a bad outbreak didn't develop because it wasn't going to, or because of the early aggressive response (i.e. did it get better because of what they did or despite what they did). However, if you sit back and wait (or remain in denial), you can be sure that it's much more likely that badness will develop.
Once things have settled down, people sometimes complain that an aggressive response was unnecessary because nothing bad happened, but they're often the same people that complain that not enough was done when an major outbreak occurs. An ongoing challenge in infection control is fighting complacency, since successful infection prevention and control programs sometimes lead to people forgetting about the bad things that can happen and why such programs are in place to begin with. We should applaud facilities that "suck it up" and accept the negative PR, time and financial consequences of an appropriate response in order to protect the health and welfare of the animals for which they care and all the people (employees and public) who have contact with them.
I'm not really sure what to think about canine norovirus. Is it a rare, oddball infection or is it an important, overlooked and/or emerging problem?
- There are only a few reports of norovirus infections in dogs, but I doubt many people are looking for it.
- I've looked for it a few times during outbreaks, but not enough to convince me it's not here.
- Most outbreaks of canine gastrointestinal disease are not investigated, and norovirus testing isn't commonly available.
So, I think it's hard to say much about this bug at the moment.
However, another outbreak report involving canine norovirus (Mesquita and Nascimento, Transboundary and Emerging Diseases 2012) has been published, increasing concern that this might be an overlooked or developing issue. This latest report from Portugal describes an outbreak in a kennel that started after the introduction of some dogs imported from Russia (yet another example of the problems that can occur with dog importation, especially in the absence of good quarantine and infection control practices).
The outbreak started after two dogs from Russia were brought into a Portuguese kennel. Both had diarrhea at the time of arrival (strike 1 - introduction of new dogs, particularly sick dogs, is just asking for an outbreak) and were put into the general dog population (strike 2). Two days later, the other five dogs in the kennel developed diarrhea (not surprising). All were positive for canine norovirus (ok, that's surprising) and within one week, all the dogs appeared to have fully recovered.
There's no mention of whether testing for other causes of diarrhea was performed, but I assume that's the case. The sudden onset, rapid transmission and relatively short, self-limiting course of disease is consistent with norovirus infection.
Canine norovirus has been found in Portugal before, and the virus found in these dogs was very similar to previous Portuguese isolates. Whether that means the dogs acquired the virus in Portugal en route to the kennel or whether this virus is widely disseminated internationally isn't clear (in large part because so few people have looked for canine norovirus).
Much more remains to be learned about this virus. It should be considered in outbreaks of diarrhea in dogs, especially outbreaks involving rapid transmission between animals. A major obstacle to obtaining more information about this pathogen is the general failure to investigate outbreaks in which it may be involved. While outbreaks are often dramatic, testing is usually limited because of the cost. That's especially true when dogs aren't dying. Often, testing for rare or potentially new problems only occurs when there's a complete disaster and/or if an interested researcher or diagnostic laboratory gets wind of it and is willing (and able) to do some testing at no cost. That's not often an option. I do testing as much as I can, but I don't have any money dedicated to outbreak investigation so it depends on whether I have spare resources to put into an investigation at the time.
The risk to people from canine norovirus is not known, but is probably limited. There is some evidence of potential transmission of noroviruses from pigs or calves to people, but the risk from canine norovirus isn't clear. Common sense practices to avoid contact with diarrhea (from any animal) should be used, as much to prevent exposure to the pile of other pathogens that can be in dog poop, as to prevent potential exposure to canine norovirus.
On my way to Beth's soccer practice yesterday, I heard a blurb on the radio about how Frank Klees, MPP (Member of Provincial Parliament) told the legislature that the Newmarket OSPCA was going to euthanize all their animals because of a ringworm outbreak, and that three employees had been fired because they objected to the number of euthanasias. His statement that "We have a repeat now, at the same shelter, of what took place nearly a year and a half ago" was pretty concerning, given the severity of the earlier "ringworm" debacle. Klees, the veteran PC party MPP, has been a vocal critic of the OSPCA in the past.
Later that night, I found a little more information, which was mainly centred around complaints about the number of animals being euthanized for various reasons, and a subsequent statement by the OSPCA that there was no outbreak.
Now, it appears that a protest is being planned for today (Friday), although it's not really clear to me what they are protesting. Maybe there's more to it than is being reported and an outbreak or cull is actually underway. However, in the absence of that, their protest is better directed at the state of the animal population rather than OSPCA euthanasias.
While I don't have a lot of confidence in Newmarket OSPCA management at this point, it's hard to blame the them for euthanizing a lot of animals. It's a function of supply and demand, as well as limited capacity.
North America wide, the euthanasia rate for cats entering shelters is about 50%. That's a staggering number, but it's not usually the fault of the shelter system - it's because of the massive overpopulation of cats. When twice as many cats come in as there are available homes, something has to give. You can either build new shelters every year (obviously unrealistic), pack current shelters to the ceiling with cats crammed into crates in every corner (a perfect situation for a large outbreak and hardly fair to the cats) or euthanize many and focus efforts and resources on the most adoptable animals. As much as the "no-kill" concept has market appeal, it's completely unrealistic for cats at this time because of the simple fact that millions of new cats are born every year with no hopes for a home. A small shelter can run as a no-kill shelter, but that just means that they limit their admissions and/or don't accept cats with limited adoption potential. A large shelter like Newmarket that takes whatever cats arrive will euthanize many of them, even without an outbreak going on. In fact, to do things right, a large shelter has to euthanize lots of cats to allow them to properly care for and find homes for other cats. Sad but true.
So, while euthanasia is obviously undesirable and it gets people worked up, yelling at the OSPCA doesn't do anything. They're not going to stop euthanizing cats, because they can't. Efforts are better spent helping deliver care to stray animals and preventing the cat population from expanding.
One of the most important things anyone can do to help the problem is make sure to (as Bob Barker used to say) have your pet spayed or neutered (and pass the message along to those you know as well!).
An 8-week-old puppy in Van Buren County, Michigan has died from infection by a virus that normally infects horses. This is a rather rare occurrence of a nonetheless devastating infection. The puppy was euthanized after developing seizures and other neurological abnormalities, and Eastern equine encephalitis (EEE) virus infection was ultimately diagnosed. Testing for this and other viruses was probably undertaken because of concerns about rabies.
EEE virus is a mosquito-borne virus that circulates in the bird population and is spread by mosquitoes. Horses are the main victims of infection but disease can occur in various other mammals, including people and dogs.
Canine infections are very rare and this can be considered an "oddball" infection. There's no evidence that dogs are at any elevated degree of risk compared to previous years, but it is a reminder that while infections are rare, dogs can be susceptible to EEE. The puppy's young age probably played a role and certain groups (e.g. puppies, elderly dogs, dogs with compromised immune systems) are presumably at greater risk of illness than the normal dog population. The other obvious implication of this report is that it is clear that EEE is circulating in mosquitoes in the area. That means other susceptible species, namely horses and people, are also at risk of exposure.
EEE in people is pretty high on the badness scale. It's fortunately rare but when it strikes, it's usually fatal. The same is true for horses. There is a vaccine for horses but not for people, so the main protective mechanism for people is mosquito avoidance.
As with EEE in horses, infected dogs pose no real risk to humans. The virus is not spread by regular contact and dogs don't develop high enough viral levels in their blood to be able to infect more mosquitoes (who could then infect people). There's a potential risk of transmission through contact with infected tissues during post mortem examination (necropsies) but standard practices used to prevent transmission of other diseases (e.g. rabies) should be effective for EEE as well.
The US Centers for Disease Control and Prevention's National Institute for Occupational Safety and Health has launched a website entitled Veterinary Safety and Health. It's designed to provide occupational health and safety (including infection control) information for people in the veterinary field, as well as people in zoos, animal shelters, kennels and other animal-contact situations. It's largely designed to be a central resource to link to available information (which makes more sense than trying to re-invent the wheel), combining a range of topics from general occupational safety to veterinary-specific infection control, hospital design and related topics. Worms & Germs Blog is included as one of the links in their resources list under Hazard Prevention and Infection Control.
After being a relatively rare problem in most regions over the past few years, West Nile virus (WNV) case numbers have boomed lately, with large outbreaks in some US states.
Forty-nine (49) confirmed or probable human cases have been reported in Ontario, the largest number in a decade. Considering we're just heading into the typical peak WNV season, it's quite concerning as the worst may be yet to come. At this time last year, there were only 24 reported cases.
Human cases have been reported in at least four other provinces: Alberta, Manitoba, Saskatchewan and Quebec.
Two equine cases of WNV have been reported, one in Saskatchewan and one in Quebec. It's hard to have a lot of confidence in this number because of the poor surveillance and reporting for this disease in animals in Canada, given that the CFIA has largely washed their hands of dealing with it. Infection with West Nile virus has been pretty much a non-entity in most regions over the past few years, at least in terms of diagnosed cases, and it remains to be seen whether equine cases will mirror the spike in human cases this year. Typically the trends are similar each year, so the next few weeks will tell us a lot.
The US is in the midst of its largest WNV outbreak ever. At least 1118 human cases have been reported so far in at least 37 states, with at least 41 deaths. Typically less than 300 cases are reported by this time of year. Texas has experienced a huge outbreak, accounting for about half of the US cases.
There hasn't (apparently) been a surge in equine cases, with less than 100 cases of WNV reported in horses as of August 18. Whether that's because of infrequent testing, biological or geographic factors resulting in less equine exposure or vaccination of horses (remember that there is no WNV vaccine for people) isn't clear.
Concern is being raised about risks to pets, but the true risk is very limited. While WNV infections have been reported in dogs and cats, these are extremely rare and dogs and cats are failry resistant to the virus.
Often, when a new infectious disease emerges, the first year or two are the boom years, after which things settle down. That was the pattern with WNV in most areas; however, this year in on track to meet or surpass the numbers from those early years.
Why is this happening? No one knows for sure. Changing weather patterns, by chance or through the larger spectre of global warming, are probably playing a major role. Warmer temperatures let mosquitoes mature faster and allow the virus to grow quicker in the mosquitoes. Milder winters help mosquitoes survive. Any factor that fosters more mosquito numbers and growth, particularly the subset of mosquitoes that bites both birds (the reservoir of the virus) and people, can increase the risk of human and animal exposure. Changes in rainfall, wetland management, climate and human proximity to mosquito breeding sites can all play a role.
'Tis the season for ringworm, I guess.
The Guelph Humane Society has closed to visitors, and adoptions have been suspended in response to concerns about the potential for a ringworm outbreak. Implementing a proactive response, all animals are being tested for ringworm and all cats are being treated. While the scope of the problem isn't yet clear (and hopefully it's minimal), this type of response is the optimal approach because waiting to "see what happens" and waiting for culture results (which can take a long time) before deciding to take aggressive measures results is a much greater chance of things getting out of hand.
In an outbreak like this, the first week or so is critical. Introduction of an animal that's carrying ringworm is hard to prevent, as is limited transmission within a shelter (even with good routine infection control practices) from that first case. That's the non-preventable component of shelter diseases. However, it's the 2nd generation of transmission (transmission of ringworm from that initial animal or group of animals to the broader population) that leads to things getting out of control. That's the preventable fraction of infections, on which we can have the biggest impact. It's during this early phase where intervention is critical It's always better to have an overly aggressive response and simply tone it down after a few days, than to have an inadequate response that lets things spiral out of control.
More information about ringworm can be found on the Worms & Germs Resources - Pets page.
The scope of the outbreak isn't really clear from press reports, but "a couple" of other animals now have signs of the skin disease. Investigation of the timing and likely sources of exposure of new cases is crucial. They may just be animals that were infected early, before the problem was recognized (the best case scenario) but investigating these "new" cases is very important because if these animals were exposed after the outbreak was identified, then there are problems with containment.
Shelter personnel have declared that they aren't planning on euthanizing more animals, but the shelter remains closed for adoptions. Stray animals will continue to be accepted. This creates a tricky situation where new animals (e.g. fuel for the fire, if things aren't under control) come in and can actually propagate the outbreak. It also creates overcrowding issues since the shelter was probably pretty full to start with, and continuing admissions with no adoptions can't be maintained for long. The shelter is looking at renting units in which to put animals - this is a relatively common approach for creating more contained spaces, and one that can be useful if good infection control practices are in place (although I've seen too many outbreaks where the offending pathogen quickly makes its way into the new units). Clear policies, sound training, careful supervision, exquisite planning and good communication are critical for making a situation like that work.
While the shelter has gone from an unrealistically optimistic time frame to a warning about long-term efforts, as with most things in life, the middle ground is usually the most accurate. Ringworm outbreaks can't be declared over in a few days (it's possible to contain it in a short period of time, but not declare an outbreak over). A few days isn't even enough time to get culture results back to figure out exactly what's happening. Testing, isolation, cohorting, mass treatment, evaluation of training, evaluation of infection control practices, and similar measures are needed, but if done right, an outbreak can be contained in a reasonably short period of time. Given the need to repeatedly treat all animals (affected animals are being bathed every three days with a medicated solution) and the time lag for ringworm culture, it's going to take at least a few weeks, but let's hope this outbreak ultimately gets measured in weeks rather than months.
It might just be my perception, but it seems like there are a lot more reports of nasty dog bite infections in the news lately, particularly infections caused by the bacterium Capnocytophaga canimorsus. I don't know whether that's because they are becoming more common, more commonly diagnosed (since the bug is hard to identify), more commonly reported in the press or a combination of all three (or whether my perception is simply incorrect).
The latest report is from Omaha, Nebraska, where a 50-year-old man died four days after suffering a minor dog bite on the cheek. The cause of infection wasn't reported, but the article says that he was unable to fight the infection because he didn't have a spleen. For me, minor bite + fatal infection + no spleen = Capnocytophaga infection until proven otherwise, since this is a textbook description of such an infection, and Capnocytophaga can be found in the mouth of virtually every dog.
This follows the high-profile case of a cancer survivor who lost her hands and feet from Capnocytophaga infection complications and a UK inquest into the death of a man caused by infection with this bacterium, among other cases.
Here are the simple take home messages:
- Avoid bites and any interactions whereby dog saliva may come in contact with non-intact skin.
- Know if you are at high-risk for an infection caused by a bug like Capnocytophaga. This bacterium typically doesn't cause disease in healthy individuals but can produce rapidly fatal disease in certain people.
- Realize that minor bites can cause major problems (even if you are otherwise healthy).
- Use good first aid practices if you or someone you're with is bitten, including careful washing of the wound and seeking medical care if you are at increased risk of infection, or if the bite is over the hands, feet, face, joints or other sensitive areas.
The facility was closed to the public on August 4th because three cats and one dog were showing unspecified signs of ringworm.
Samples were collected for testing, but they decided to euthanize the 4 animals.
"You’re kind of under the gun to decide what you want to do,” said their operations manager. I can certainly empathize. It's not easy to deal with an outbreak. However, from my standpoint, if you feel like you're under the gun in that kind of situation, you're likely to make (or to have already made) mistakes. If you're managing the situation well, getting advice and following standard practices, you may be stressed, exhausted, humbled and concerned, but you shouldn't feel "under the gun." Maybe euthanasia was warranted here, but with a small number of infected animals, the ability to potentially isolate and treat them, and lots of information about how to manage ringworm to avoid further spread, it's important to avoid a panic response that leads to premature euthanasia decisions.
The three cats that were euthanized apparently did not have ringworm, but the shelter is "certain" (not sure how) that the dog had ringworm. Sudden onset of skin lesions in dogs and cats at the same time is certainly suggestive of ringworm, and if the dog was truly infected, it's hard to believe the cats were not (especially since cats are most often affected in ringworm outbreaks compared to dogs). So I wouldn't be too quick to rule out ringworm in the cats. Ringworm culture can take a couple of weeks, so it's not clear to me whether this interpretation is based on culture results or not.
"With the results being better than expected, the humane society will not have to move larger numbers of possibly infected animals to a different facility — the usual procedure in an outbreak." While I can't say too much from a distance, I can say that moving animals to another facility is certainly not a typical outbreak response measure. It's an effective outbreak propagation measure, since it can easily disseminate ringworm to other places, so it's good to hear that they are not planning on moving animals. It's much better to manage things well at one site than to have to manage things at multiple sites.
They state that "the situation now appears to be under control." Hopefully that's true, but it's way too early to say. You can't declare an outbreak over a few days after you declare that it started. There hasn't even been enough time for any animal or environmental ringworm culture results to come back. Closing, testing, treating all exposed animals and thorough cleaning and disinfecting of the environment can be a great start, but trying to say "we won" too early often leads to inadequate response and continuation of the outbreak.
"We’re keeping our fingers crossed and hoping that everything comes back negative so we can be open for business sometime next week" Again, I'm not involved and I'm working with sparse information, but this seems to be way too early to reopen the shelter. You need to make sure things are really under control before you get out of "outbreak mode" and before you can be "open for business" again. That's especially true with a disease like ringworm that is highly transmissible and can be spread to people. Too often, a small outbreak is identified and declared over prematurely, only to be followed by a big mess in short order. Let's hope that's not the case here.
Image: Photo of a dermatophyte-positive culture specimen, which can take two weeks or longer to grow.
Let me say it again... yes, dogs can get salmonellosis.
...and in French, oui, les chiens peuvent devenir malades de salmonellose (hope that's close)
...and in Swahili, ndiyo, mbwa anaweza kuwa na wagonjwa salmonellosis (thank Google Translate for that one).
What prompted my recurrent 'yes dogs can get Salmonella rant'? Another fluff piece on feeding dogs raw meat diets, this time in the Globe and Mail (a national paper in Canada).
The "dogs can get Salmonella" rant doesn't actually stem from the newspaper, since the article didn't even bother to get into potential infectious disease or nutritional deficiency concerns with these diets (in-depth reporting it was not). Rather, the rant is in response to comments on the paper's website that include the typical garbage that dogs are not susceptible to Salmonella because of their short and acidic intestinal tract. It's a fallacy that's widely distributed on the internet on raw pet food sites, and it's wrong (although ironically enough, many of these same sites also talk about how dogs get sick from Salmonella from commercial foods).
To set the record straight:
- Dogs can get Salmonella.
- Most often they don't get very sick, but sometimes they die.
- Ingesting Salmonella from food or other environmental exposures is the source.
- The more Salmonella a dog eats, the greater the risk of disease.
- Raw meat is often contaminated with Salmonella.
Now that I've gotten that off my chest, I'll get back to the article. It's written by someone who feeds her dog raw meat. I have no major problems with that for the average dog and average person. It increases the risk of salmonellosis in the dog and in the family (and potentially anyone or anything in contact with the dog or its poop), but the risk of infection for your average, healthy dog and person is relatively low. It's a bigger issue when there are high risk people or animals in the house, and human and pet infections from feeding raw meat certainly do occur.
I'd rather people not feed raw (or at least make sure they feed high pressure pasteurized raw meat) but I'm a realist and I realize some people are going to do it anyway. I therefore focus on trying to educate people about situations when they really shouldn't feed raw meat (e.g. high risk dog or person in the household, young growing animals) and what to do to decrease the risk of transmission of Salmonella. More information of this kind is available on the info sheet that can be found on the Worms & Germs Resources - Pets page).
Anyway, back to the article (I really mean it this time). The article includes some interesting information, particularly the very high cost of feeding a raw diet compared to commercial dry or canned foods. However, it also contains some of the same drivel that's found in most of these articles. For example:
"'Dogs don’t have microwaves or grocery stores in the wild,' she says with a laugh, adding that she believes a dog that eats raw will lead a longer, healthier life than one fed traditional dog food."
- They also don't necessarily live long, happy and healthy lives in the wild. Today's domestic dog is long removed from the mystical wild dog. My dog Meg wouldn't make it very far in the wild, unless there are dog food trees somewhere that I don't know about.
"'On a kibble diet, her dogs were 'overweight, with no energy - scratching all the time from all the allergies,' she says. 'These were our fat, miserable, lethargic dogs.'"
- Less food, more exercise and good veterinary care could probably have taken care of that too.
As I said above, people are free to make their own choices, but they should get informed, and they need to go beyond raw food company websites and support groups. They need to think about potential benefits, potential risks, cost, hassle and other factors to determine if it's right for them and their dog. Getting real information and critically assessing the information that's out there are critical steps.
I've had a run on questions about survival of rabies virus outside the body. The topic comes up periodically with respect to touching roadkill or veterinary clinic personnel working with animals that have been attacked by an unknown animal. The case of three people who developed rabies after taking care of a sheep that had been attacked by a rabid animal, probably through contact with saliva from the rabid animal on the sheep's coat coming into contact with broken skin on their hands, shows the potential risk. An important part of assessing the risk is understanding how long the virus lives outside the body.
Some viruses are very hardy and can live for weeks or even years outside the body. Parvovirus and norovirus are classic examples of this type. Some viruses, like HIV, die very quickly in the environment. Part of this relates to whether they are "enveloped" or "non-enveloped" viruses. Enveloped viruses have a coating that is susceptible to damage from environmental effects, disinfectants and other challenges. Damaging this coating kills the virus. Non-enveloped viruses don't have that susceptible coating and that is in part why they are so much hardier.
Fortunately, rabies is an enveloped virus, and it doesn't like being outside of a mammal's body. Data on rabies virus survival are pretty limited, since it's not an easy thing to assess. To look at rabies virus survival, you have to grow the virus, expose it to different environmental conditions, then see if it's still able to infect a mammal or a tissue culture. We can do this easily with bacteria, but growing viruses is more work, especially a dangerous virus such as rabies virus.
I can only find one study that has looked at rabies virus survival (and I can only read the abstract since the rest of the paper is in Czech). The study (Matouch et al, Vet Med (Praha) 1987) involved testing of rabies virus from the salivary gland of a naturally infected fox. They exposed the virus to different conditions and used two methods to look at the infectivity of the virus.
- When the virus was spread in a thin layer onto surfaces like glass, metal or leaves, the longest survival was 144 hours at 5 degrees C (that's ~ 41F).
- At 20C (68F), the virus was infective for 24h on glass and leaves and 48h on metal.
- At 30C (86F), the virus didn't last long, being inactivated within 1.5h with exposure to sunlight and 20h without sunlight.
So, rabies virus can survive for a while outside the body. Temperature, humidity, sunlight exposure and surface type all probably play important roles, but in any particular situation you can never make a very accurate prediction of the virus's survival beyond "it will survive for a while, but not very long."
From a practical standpoint, it just reinforces some common themes:
- People should avoid contact with dead or injured animals.
- Veterinary personnel or pet owners dealing with a pet that has been attacked by another animal should wear gloves, wash their hands and take particular care if they have damaged skin.
- People who are at higher than normal risk of being exposed to potentially rabies-contaminated surfaces should be vaccinated against rabies.
Image: Schematic diagram of a rabies virus showing the outer viral envelope (source: CDC Public Health Image Library)
When I'm giving talks about zoonotic diseaes to people in the human healthcare field, I sometimes mention tuberculosis (TB) as an example of a serious human disease with poorly defined (but theoretically important) risks of transmission between people and pets. TB is a very important disease of increasing of concern because of its resurgence in many areas and the spread of drug-resistant strains.
We don't know much about TB and pets. There are some older studies that provide conflicting information, suggesting that Mycobacterium tuberculosis, the bacterium that causes TB, can be commonly or rarely isolated from dogs owned by TB patients.
A recent study from South Africa (Parsons et al. Research in Veterinary Science 2012) provides more information. The study involved two main components:
- For the first component, they examined 100 stray dogs in Cape Town, South Africa, for evidence of TB. The dogs were being euthanized for population control purposes so the researchers were able to do necropsies (post-mortem exams) to look for the bacterium and signs of disease that may not have been outwardly apparent. They isolated the bacterium from 4% of the dogs, with only one of those having any signs of disease. That shows that TB is present in dogs in the area, albeit at a low rate. The fact that 3 of 4 TB-positive dogs had no evidence of disease is both good and bad. It's good for the dog's health that illness doesn't always occur (just like in people), but it also means that apparently healthy dogs can be carrying this concerning bacterium. The risk of transmission from healthy carriers isn't known. It's probably rather low since close and prolonged contact are required to transmit TB between people, and healthy carrier dogs are probably not shedding many TB bacteria through their respiratory tract. Greater concerns are probably present in dogs with TB infection of the lungs who are coughing and spewing TB bacteria into the air.
- The second component of the study involved testing of 24 dogs living with people with TB. They used two different tests: the TB skin test (a test that's commonly used in people but one that's been typically considered useless in dogs) and an interferon gamma release assay (IGRA)(a test more commonly used now in humans). They concluded (not surprisingly) that the skin test was pretty useless, but their data suggest the IGRA may be a good test for dogs. 50% of dogs in those households had evidence of TB exposure through IGRA, consistent with one older study that indicated transmission of TB from people to pets may be common.
What are the implications of all this?
For the average person and pet, not much. TB transmission requires close and prolonged contact with an infected individual. You don't get it walking down the street behind someone with TB.
The concern is in situations when people with TB may have contact with pets - the same concern as in situations when people with TB may have contact with other people. The potential for transmission is something to pay attention to in households where there is an infected person, or in populations where there may be high TB rates and common pet contact (e.g. some homeless populations).
Results of this study should be a reminder that when considering who's potentially been exposed to a person with TB and making plans to reduce the risk of transmission, you need to consider all individuals - human and animal - with which the person has contact. Therefore, measures taken by people to avoid transmission of TB to other people should be equally applied to reducing transmission to pets. Pet exposure should always be considered, particularly when dealing with multidrug-resistant (MDR) or extensively drug-resistant (XDR) TB, since such strains are huge concerns in people and we don't want to create canine or feline vectors of these strains. The study results also indicate that pets owned by TB patients may be at increased risk of disease from TB, not just at risk of being infected and harbouring the bug. Therefore, knowing that a pet has had close and prolonged contact with a person with TB is relevant to veterinarians when evaluating sick animals.
Travel always carries a risk of infectious diseases. More people are paying attention to their health and going to travel clinics to find out about these risks and what preventive measures they can take. They still constitute only a minority of travelers, but it’s an improvement. There aren’t travel clinics for pets, so travelers thinking about pets and infectious diseases need to rely on sources like their regular veterinarians and government websites.
Unfortunately, that doesn’t always result in good information, as shown in a study recently published in Zoonoses and Public Health (Davidson et al 2012). For the study, the authors called veterinary clinics in eight European countries (Austria, Belgium, Finland, France, Germany, Sweden, Switzerland and the UK) and asked them about taking a dog to Norway. They also called clinics in Norway and asked about bringing a dog to the country from an unspecified location in Europe. Calling was done not as a research survey but by a person pretending to be a pet owner.
The study focused on two main pathogens, Echinococcus multilocularis (a tapeworm that is present in some parts of Europe but not others, and one that is both an animal and public health concern) and rabies. Only 9% of clinics provided accurate information about these two problems. Some clinics (58%) referred people to government sites that have good information, but unfortunately 13% of clinics referred people to websites or government agencies that provided incorrect or incomplete information. When information from websites is included, people received correct advice 62% of the time. Not bad but not great.
Among the bad advice that was given (or important information that was not given):
- Failure to tell people about the requirement for tapeworm treatment after arrival.
- Incorrect tapeworm treatment information.
- No mention of rabies titre testing.
- False information that pets traveling to Norway don’t require tapeworm treatment.
This shouldn’t be taken as indicating that veterinary clinics aren’t competent. Travel medicine certainly isn’t something I was taught in vet school. Most veterinarians (understandably) don’t spend much time reading about problems that only occur in other geographic regions, since there’s enough other new information on which they must stay current. So, they may not have answers at the tip of their tongues when asked a question. Trying to get good information by random phone calls or as an aside during a veterinary appointment might not be the best approach. However, since we have a surprisingly mobile pet population, with pets traveling with owners to many different regions, it’s an important area for veterinarians to think about, from two standpoints:
1) Counseling people who are traveling: As was the focus here, it’s important for people to know about disease risks and regulatory requirements for places to which they travel. Specific preventive measures (e.g. vaccination, deworming) that are not needed at home may be indicated when traveling.
2) Diagnosing disease in returning animals: It’s easy to miss travel-associated diseases, and that can lead to bad outcomes. If veterinarians don’t ask whether a pet has traveled, they won’t realize that there might be some other diseases to consider. If they don’t know about disease concerns in other regions or (perhaps more importantly) don’t have ready access to good information about disease risks in other regions (e.g. accurate websites), they might not consider important diseases even if they ask about travel history.
This study highlights a few of the current gaps in the system, involving background knowledge, client communications and variable accuracy of electronic sources. People who are traveling with pets (or acquiring pets from abroad) should have a thorough discussion with their veterinarian (not just a casual call to the veterinary clinic, during which information may come from or through lay staff) about the situation, and they need to do their own homework. It's probably best to make sure the clinic knows that there will be travel questions in advance, so mentioning it at the time of booking the appointment might help.
As the authors of this research state “An accessible, centralized, easy to use website, that is updated by a central regulating agency and applies to all countries, would allow veterinarians to refer pet owners to one site for further information regardless of which country they are travelling from and going to.”
That's the ideal situation. Given the minimal attention that governments pay to pet animals, it's probably going to have to be an government-independent, collaborative venture. We've had some discussions about this in the past and it would be great to do, but the logistics are a bit daunting. Maybe it's time to resurrect those discussions.
Israel's Health Ministry is recommending rabies vaccination for people traveling to India.This seems to be mainly in response to the recent high-profile case of an English woman who died of rabies acquired from a dog in India. While it was high-profile, that certainly wasn't the only travel-associated rabies infection in the past year. Rabies exposure is a serious concern for people who might encounter dogs (intentionally or accidentally) while traveling in countries with endemic canine rabies. The news report states that rabies vaccine is available at clinics in Israel for would-be travelers, however it doesn't say whether the cost of vaccination is covered by the government. Human rabies vaccination is quite expensive, which may be a limiting factor when it comes to convincing travelers to get vaccinated, unless the government foots some or all of the cost.
Raising awareness of the problem with rabies in some developing countries is good. Most people don't really think about travel-associated disease (beyond the ubiquitous diarrhea that comes with travel to some areas), particularly something like rabies. In addition to focusing on vaccination, however, it would be even better to see a broader initiative to remind people to avoid contact with stray dogs (and other animals) and to make sure they get proper medical care after potential rabies exposure. Also, while India is certainly a hotbed of canine rabies, it's important to remember that there are many other countries where dog rabies is a major problem, and similar measures need to be taken for travel to these places too.
A surprisingly large number of people get sick and die every year from diseases acquired during travel. Travelers need to be aware of disease risks in areas they visit, know what preventive measures they should take and how to get proper medical care in any region they visit. While thinking about this might put a damper on vacation planning, it's worth the effort. When it comes to rabies, unless you know that a region is officially (and truly) rabies-free, assume that any encounter with a wild mammal, especially a stray dog, could be a source of rabies exposure. You don't want to travel in a bubble and stick to sterile locales, but you also don't want to come down with a fatal disease when some basic precautions could have prevented it.
While rabies is classically transmitted from animals to people by bites, any situation that allows saliva from an infected animal to get past the body's protective skin barrier can result in infection. Graeme Anderson, a 29-year-old South African canoeist, recently died after contracting rabies from a sick dog for which he was caring. There was no history of a bite, but the dog had licked damaged skin on the man's hands, allowing the virus to enter the body.
Any contact with animals showing signs consistent with rabies needs to be investigated. Licks over damaged skin (or mucous membranes like the mouth) are classified by the World Health Organization as having the same level ("severe") risk of rabies exposure as bites, and post-exposure prophylaxis is indicated. Bites are the main source of rabies transmission, but not the only source, the fact of which situations like this remind us.
It's not the first, and it's a safe bet it's not the last, but a lawsuit has been filed against Diamond Pet Foods in response to a case of salmonellosis in a New Jersey infant. The lawsuit claims (probably correctly) that the infant acquired Salmonella from contaminated dog food that was in the household. The infant was hospitalized for three days but recovered. The lawsuit, one of at least eight that have been filed, claims negligence and fraudulent representation, and is seeking over $75000 in compensation.
In reality, it's hard to consider a company liable simply for Salmonella contamination. Various practices can be used to reduce the risk and to detect contamination when it occurs, but these will never be 100% effective. Standard hygiene practices that are recommended to reduce the risk of exposing people (especially high risk people) to any pathogens that might be found in pet food must therefore always be used. It's hard to say what degree of responsibility needs to be placed on consumers versus companies, since companies need to do their best and people need to use common sense.
From my completely non-legal standpoint, the issues of negligence and liability come in when:
- A company has inadequate facilities that do not conform to standard requirements to reduce the risk of contamination (e.g. duct tape and cardboard in food processing equipment, as per the FDA report).
- A company has an inadequate quality control program.
- A company knows there's a problem and doesn't take prompt and appropriate action to correct it.
Based on what information has been released (including the relatively damning FDA report that cited lack of microbial analysis of certain ingredients, lack of hand hygiene facilities and the use of duct tape, cardboard and other non-cleanable materials in the plant) combined with some questionable communications strategies, it certainly seems like a case can be made here.
People like to talk about "one medicine" a lot. It refers to the concept that we're all animals, and that human and veterinary medicine should be one big happy family of healthcare providers that maintain the health of the entire family, human and non-human. I get a bit jaded talking about one medicine because there's a lot of talk but it's hard to get a lot of action. One problem is that while some people in both human and veterinary medicine are strong supporters of the one medicine concept, it doesn't always filter down to the ground level.
A study in the latest edition of the Journal of the American Veterinary Medical Association (Hill et al. 2012) presents some concerning but not surprising information about "Tennessee veterinarian and physician attitudes, knowledge and practices regarding zoonoses prevention among animal owners with HIV infection or AIDS."
The study consisted of a survey sent to 454 vets and 1737 physicians in Tennessee. Response was pretty poor (a common problem with surveys), with only 43% of vets and 15% of physicians completing it. You have to wonder why the physician rate was so low. One potential issue is that the topic is not even on the radar of most physicians so they didn't bother to respond. If that's the case, then the people who responded could be more interested than average, potentially biasing the results (meaning that the problems described below are actually underestimated).
Here are some highlights from the study:
73% of veterinarians, but only 50% of MDs, said that veterinarians should always or almost always be involved in advising clients with HIV/AIDS about zoonotic disease risks.
- Considering a large percentage of physicians don't initiate the discussion and don't get any additional education in zoonotic diseases (see below), I'm not sure what the other 50% of physicians think should be happening in terms of zoonotic disease counseling.
58% of veterinarians had zoonotic disease educational materials available in their clinics compared to only 3.5% of MDs.
- Not surprising at all. Actually, the fact that some MDs have info in their offices is a bit of a surprise.
Only 5% of MDs had any continuing education (CE) on zoonotic diseases in the past three years, compared to 29% of veterinarians.
- Pretty pathetic numbers all around. Veterinarians probably have easier access to this kind of CE since zoonotic disease topics are commonly presented at veterinary conferences, although attendance tends to be limited (as evidenced here). It would be nice to know why almost no MDs have had CE on zoonotic diseases. Is it lack of interest? Is it lack of availability? These are two completely different issues that can be addressed differently.
Almost 70% of veterinarians reported regularly talking to pet owners about the risk of zoonotic diseases in people with compromised immune systems.
- One problem here is knowing with whom to have the talk. Asking people their medical history isn't (logically) part of the normal pet examination process, and while it's good information to have, veterinarians aren't going to cross that line and routinely ask those types of questions. That raises the question about how to initiate the discussion, and a crucial factor is having pet owners who are willing to bring up the subject. For that to happen, they need to realize that it's relevant, that the veterinarian knows something about the topic and can help, and that all information will be treated confidentially. Therefore, client education is key.
51% of physicians said they never see zoonotic infections in HIV/AIDS patients, while 44% said they almost never see them.
- In part, that's a testament to the effectiveness of highly active anti-retroviral therapy (HAART), which has had a tremendous impact on management of patients with HIV. However, it also may be an indication that MDs don't recognize some infections as zoonotic. Certainly, a patient with Salmonella would (hopefully) result in some thought about zoonotic transmission, but there are a range of other pathogens where the zoonotic risks are less clear or less well known. When you consider that 71% of MDs never or almost never ask HIV/AIDS patients about pet ownership and animal contact, you can see how discussion and consideration of zoonoses might be poor.
Only 26% of veterinarians and 33% of MDs were able to correctly identify zoonotic pathogens of greatest concern to people with HIV/AIDS.
- Pretty concerning numbers (especially among MDs, who do the diagnosing).
100% of MDs never or rarely contacted vets about zoonoses, and 97% of veterinarians never or rarely contacted physicians.
- For all the talk about one medicine, this shows how far we have to go.
We need to do a better job of actually practicing one medicine. Veterinarians and MDs need to communicate. Both groups need to realize that they play a role in zoonotic disease prevention, and that the other group has an important role as well. Zoonotic diseases is a niche field in human and veterinary medicine but that doesn't mean they should be ignored. While serious zoonotic diseases are uncommon, they occur, and the failure to actually practice one medicine means that some people are at higher risk than they should be, and infections that occur may not always be identified and managed optimally.
Image credit: UI News Bureau (click for source)
While I guess it's getting beyond the point where Hendra virus infections in horses in Queensland, Australia are considered "news," it's still a highly concerning situation. Infections caused by this fruit bat-associated virus continue to occur in the region and there's no sign that this problem is going to go away any time soon.
In the latest report, two horses from a farm where a horse recently died of Hendra tested positive for the virus. In another location, a dog is being re-tested after a weak positive test. This situation brings back memories of the debate that occurred last year after a healthy dog that tested positive was euthanized as a precautionary measure, despite no information about whether the dog could actually be a source of infection.
Hendra is resulting in profound changes in the horse industry in Queensland. Beyond being a major problem in horses, this virus can be passed from horses to people, resulting is tremendous concerns amongst horse owners and veterinarians. Many veterinarians are refusing to work with horses because of the risk and I assume that some people are selling horses for similar reasons.
Infection control practices can presumably reduce the risk of transmission of Hendra virus between horses and from horses to people, but there's no way to completely eliminate the risk. Fruit bat control strategies get discussed, ranging from removal of fruit trees from horse pasture to reduce fruit bat exposure (logical) to fruit bat culls (highly unlikely to have any longterm effect). At a minimum areas under fruit trees should be fenced off from horses, and it has also been recommended to keep water troughs covered to prevent contamination with excrement from the flying foxes. Ultimately, everyone's holding out for an effective vaccine, which has yet to appear, but work on the vaccine is well underway and the hope is that a commercial vaccine could be released as early as next year.
An inquest into the dog-bite-associated death of Gary Dickinson, age 57, is underway in the UK. When people think about deaths from dog bites, they usually think about death from severe trauma, especially in kids. However, as I've mentioned repeatedly, minor bites can also pose major risks.
Mr. Dickinson died in February, only three days after being nipped in the finger while breaking up a fight between his dogs. It was a minor bite that many people would quickly dismiss. However, trauma isn't the only possible problem with bites. Infections from bites can be very serious, and in some situations all it takes is a very small break in the skin to allow bacteria to move into the tissues.
Despite suffering no consequences from the initial trauma of the bite, Mr. Dickinson was feeling sick by the next day. He went to the hospital and was sent home with a diagnosis of food poisoning (probably based on vague signs and lack of any other obvious diagnosis, rather than any true evidence of food poisoning. A key question here is whether the dog bite was mentioned at the hospital, which is unclear to me).
Mr. Dickinson deteriorated rapidly after returning home and was rushed back to hospital. Despite aggressive treatment, he died just six hours after admission. The diagnosis was Capnocytophaga infection, and this is a pretty classic picture of this rare but devastating infection.
Capnocytophaga is a type of bacterium that is found in the mouths of dogs. Pretty much every dog has loads of it in the mouth, and people are very commonly exposed through contact with saliva. Fortunately, it rarely causes infections and usually is only a problem in people with compromised immune systems. People who do not have a functional spleen (typically because it has been removed for one reason or another) are the classical high risk group for Capnocytophaga infection. Alcoholics are another high risk group, and that appears to have been the issue in this case.
Minor bites are usually just that - minor. However, sometimes very bad things can happen following very minor bites. Serious consequences are most common in young kids, the elderly and people with compromised immune systems (especially people who have had their spleen removed). While no one should panic after a mild bite, everyone should take any bite seriously. In most situations, thorough cleaning of the wound is adequate, but bites over critical areas (e.g. face, joints, hands) or in high risk people need to be assessed promptly by a physician.
More information about bites can be found on the Worms & Germs Resources - Pets page.
The title from Food Safety News' latest report says it all: "After eight expansions, how big is the Diamond Pet Foods Recall?" It's disturbing that we can't answer that question, considering the contamination stretches back to 2011 and now it's apparent that there are problems with another one of their plants.
Accordingly to Food Safety News, the FDA has indicated Salmonella contamination has been found in Diamond's Meta, Missouri plant, in addition to the South Carolina plant that's been at the heart of the recall. However, the Missouri Salmonella contamination is from Salmonella Liverpool, a different strain from the South Carolina plant where Salmonella Infantis has been involved. So, there's no evidence that the two recalls are linked, although you have to wonder whether deficiencies that were found by the FDA at the South Carolina plant might also be present at other plants, thus creating an increased risk of Salmonella contamination.
Anecdotal information about sick animals and people associated with this recall abounds, in stark contrast to information from Diamond Pet Foods. It would be nice to have some clear communication from the company about this outbreak, and some information about what they are doing to control it and prevent it from happening again. The continued expansion of the recall and contamination is concerning, and in the absence of clear communication from the company it's hard to have confidence in the safety of any more of their products.
A 50-year-old UK woman, the first of two recent travel-associated rabies cases in the UK, has unfortunately but not surprisingly succumbed to the infection.
The woman was bitten by a puppy while traveling in India. Given the widespread nature of rabies in dogs in India and the large number of human rabies deaths associated with canine rabies there, this was a high-risk exposure. I still haven't seen any information about whether she sought medical care in India or not. Too often, people don't bother to go to a doctor after being bitten, especially if the bite appears minor - but even a minor bite can transmit rabies. Furthermore, people don't always get the care they need, since rabies treatment is astoundingly not always offered after dog bites in India, and rabies vaccine and antibody may sometimes be in short supply.
Whatever happened in India, the woman was reportedly turned away twice by doctors back home at Darent Valley Hospital in Dartford, Kent. It's not clear why, and an investigation is underway, but it's not necessarily surprising since signs of rabies can be very vague at first. Initial signs could mimic a range of minor illnesses, and if the doctors didn't know that the woman was bitten by a dog in India, rabies presumably (and reasonably) wouldn't be considered, especially since it's not present in the UK.
In what is hopefully a case of misquoting or misinterpretation, Dr. Ron Behrens of the London School of Hygiene and Tropical Medicine is quoted as saying that there is a 24 hour window after a bite when antibody treatment can prevent the virus from entering the nervous system. In reality, it's not that quick and the incubation period can be very long in some cases. Post-exposure treatment can be highly effective even if it's given well after exposure, as long as it's before signs of rabies occur. Prompt treatment is always best.
It's apparent that there's an ongoing outbreak of LDDD, a potentially fatal dog-associated problem in people in this area. It seems to be a seasonal disorder, with nice weather bringing out more cases. I've seen a couple nasty cases in the past 24 hours, including one tonight that could have resulted in the deaths of an entire family.
What is LDDD?
A new bacterial infection? No.
A new virus? Nope.
Contrary to the focus on this site, it's not even an infectious disease. It's lap dog/dumb driver syndrome.
Tonight's case was fairly classic, involving the driver of an SUV and a small dog...on the driver's lap with its head out the window. The driver had one hand (and I'm not sure how many eyes) on the dog, and the SUV swerved off the road, but fortunately not all the way into the ditch (or a pedestrian, cyclist or other vehicle).
In Ontario, it's illegal to drive while using a cell phone. Restraining a small (or not so small) dog on your lap has to be at least as distracting and it's far from rare. A little common sense goes a long way, but common sense isn't always that common.
Just as I was getting ready to write about a recent case of travel-associated rabies in the UK, a second suspected case has been identified in the UK. They're not linked and it's just a co-incidence that the two have been identified in a short period of time, but they highlight the potential risks of rabies during travel.
The first report is about a confirmed case of rabies in a woman in her 50s who was bitten by a dog in India. At last report, she was being treated in hospital, although the prognosis is presumably extremely poor if treatment was started after the onset of disease. Public health officials have investigated people who were in contact with the woman to determine who needs post-exposure treatment.
There's not much information in the most recent report, beyond the fact that a suspected rabies case was detected in a person in Leeds following a dog bite that occurred abroad. There's no information yet (at least that I've seen) about where the bite occurred, the condition of the patient or whether the person received medical care after the bite.
While travel-associated rabies is very rare, it's almost always fatal. It's almost 100% preventable too, and any cases that occur typically reflect a breakdown in knowledge, communication or medical care.
Knowledge/Communication: People need to know about rabies, and be aware that any bite from a mammal in a rabies-endemic area should be investigated as a potential rabies exposure. They need to know about the risk of rabies in areas they visit, and avoid situations that might lead to a bite. Travelers and non-travelers alike need to know to go to a physician after any bite and to ensure that rabies exposure is duly considered. Individuals traveling abroad need to know how to access the healthcare system where they are, communicate the problem and act as their own advocate to make sure things are taken care of properly.
Medical Care: With proper post-exposure treatment, rabies is almost 100% preventable. The problem is getting the treatment in a timely manner. Knowing to go to a doctor is one issue. Getting proper care once there is another, particularly in some countries where access to rabies vaccine may be limited or where the healthcare system is poor. Rabies exposure is a medical urgency, not an emergency (although the more severe the bite and the closer to the head, the more important it is for a prompt response). If someone has had a potential rabies exposure and they aren't getting proper care, they need to get home (or somewhere else) where they can obtain the appropriate treatment. That doesn't mean panicking and getting on the first flight out of the country, but it also doesn't mean waiting until your planned vacation is over. It means getting home in good time, while not freaking out if it takes a day or two.
There have been various news reports from different parts of North America describing distemper outbreak in raccoons. Distemper is a viral infection caused by canine distemper virus, which is related to the human measles virus (but the canine version can't infect people). A variety of animal species in addition to dogs can get distemper, most notably raccoons.
Distemper outbreaks are not uncommon in raccoons, and one big problem with distemper is that the neurological signs cannot be distinguished from rabies. Yes, there may be some general trends in how a raccoon with distemper behaves that differ from one with rabies, but it’s far from definitive. That creates issues because distemper is of absolutely no human health concern while rabies can be transmitted to humans and is almost invariably fatal.
A Windsor-Essex (Ontario) outbreak of distemper in raccoons highlights some of these issues and the care that must be taken with regard to public communications.
Authorities are “urging the Windsor-Essex public not to worry about a rising number of incidents with strange-acting raccoons: The poor scavengers are suffering from distemper, not rabies.”
- This is bad communication in my opinion. I’d rather see something like authorities are "urging the public the avoid raccoons because of the risk of rabies exposure, but to be aware that a raccoon that is behaving abnormally probably has distemper, not rabies." Telling people not to worry is okay, but making it seem like there's no issue whatsoever is another. No one can say for sure that all of these affected raccoons have distemper, not rabies.
A good statement appears later in the article ”(Executive Director of the Windsor-Essex County Humane Society Melanie) Coulter stressed that although the disease is highly contagious among animals, it can't be passed to humans. But she added that raccoons with distemper are still capable of sudden aggression, especially if they feel cornered. As well, the symptoms of distemper are similar to those associated with rabies -- and the difference can't be determined without lab testing.”
- That’s much better. It highlights the problem and explains that it’s probably not a risk to people, but also makes it clear that you can’t be sure it’s not rabies.
The key thing is avoiding contact with raccoons all of the time, with particular attention to raccoons that are acting abnormally, since they are more likely to have rabies and they can be unpredictable. Some other things to consider:
- Don’t keep raccoons as pets (common but illegal, at least here).
- Don’t encourage raccoons to live around your home.
- Keep pets away from wildlife.
- Ensure dogs (and cats) are vaccinated against rabies and distemper, in case they have an unexpected incident with a raccoon.
The large recall and salmonellosis outbreak associated with a variety of foods produced by Diamond Pet Foods continues to expand, in terms of species involved, the number of cases, the number of recalled products and geographic scope. The only thing that's not expanding in information from the company.
Reports (of varying strength) of Salmonella cases in dogs have been cropping up, but it's not just a US problem or a problem only involving people and dogs anymore. Two cats from a Montreal animal shelter have apparently died. At least two people in Canada have also been infected, one each from Quebec and Nova Scotia.
As with many outbreaks, the depth of information is variable when it comes to potential cases and it's hard to say if everything that's reported in the press is real. Just because an animal has been eating recalled food and gets sick, that doesn't mean that the food caused the disease. Testing is required to make the diagnosis of salmonellosis and confirm the involvement of the outbreak strain. However, enough reports are coming in to be fairly convincing that this is a very large, wide reaching outbreak involving people, dogs and cats, and multiple countries.
Communication is critical when managing an outbreak. It can let companies show they are doing everything that's necessary (and more), demonstrate their commitment to correcting the problem, show how they are helping people with affected animals, and provide confidence that once the problem was identified, it was (or will be) rectified and the product can be considered safe. Some companies shine during outbreaks. Some don't.
Here, communications don't seem to be ideal.
- Another product was added to the recall list, without too much publicity.
- We know recalled food is in the US, Canada and Puerto Rico (with sick people and animals in at least Canada and the US), but has contaminated food gone any further? Importantly, has information about the potential risk gone anywhere the food might have gone, since the FDA's mandate ends at the US border. eFoodAlert reports some concerning information in that regard. The Taste of the Wild website lists over 50 countries where the food is available and a correspondent for the site apparently bought a recalled product in Ireland. What is actually being done to correct problems that lead to the outbreak is also unclear.
- I also haven't seen any press releases from the company addressing the numerous FDA violations that were identified in the outbreak investigation.
Outbreaks happen. Sometimes they're not preventable. Sometimes mistakes happen. That's an unfortunate aspect of life. However, how a company deals with those issues, both in terms of correcting the problem and restoring consumer confidence, is critical, and seems to be lacking here.
A good adage when it comes to outbreak communications is "never announce a problem without announcing a solution." That doesn't mean hide outbreak information (something that is done too often). Rather, it means don't just say that you have a problem. Be clear about your problem and at the same time be clear about what you are doing to fix it. Hopefully, Diamond Pet Foods has an aggressive ongoing response to correct these problems, and that's what consumers need to know about. In the absence of any clear information, we're left wondering whether they are doing anything at all.
I'm getting a lot of questions now about canine aspects of this recall, so I've addressed my take on some of the important issues below.
Can Salmonella cause disease in dogs?
Absolutely. The common myth about dogs being immune to Salmonella (mainly found on raw food sites) is just that: a myth. Dogs can and do get Salmonella infections, and it can make them sick.
Are dogs getting sick because of the recalled food?
I don't know but I suspect they are. There's no reason to think that the strain of Salmonella involved here would infect people but not dogs. The reason that there are reports of human but not canine cases could simply be because there is a formal surveillance and reporting system for humans but not dogs. Also, testing is not commonly performed on dogs with diarrhea, so large numbers of cases could go unidentified.
What would a sick dog look like?
The most common presentation of salmonellosis in dogs is diarrhea. Vomiting, lethargy and lack of appetite may also be present. Diarrhea can range from mild to severe and bloody. Chronic diarrhea can also develop but is less common. Other types of infections such as bloodstream infections can occur, with or without diarrhea, but these are pretty rare.
How do I know if my dog has salmonellosis?
The only was to know is to try to detect the Salmonella bacterium. This usually involves testing of stool samples. Culture is the standard and preferred approach, and is best done by a lab experienced with Salmonella testing and one where selective culture methods will be used. PCR, a type of molecular test, can also be used to detect Salmonella DNA. The quality of these tests (and the labs that offer them) is quite variable, but some of these tests are quite good. The downside is that all you find out with PCR testing is whether Salmonella is present or not. With culture, the bacterium can be tested further to see if it is the outbreak strain, and it can be tested for its susceptibility to antibiotics in the uncommon event that antibiotic treatment is needed.
My dog is healthy but has been fed recalled food. Should he/she be tested?
I don't recommend that. I only want to do a diagnostic test if I have a clear plan regarding how to use the results, which wouldn't be the case is a situation like this. If the dog was positive for Salmonella, I wouldn't do anything special except remind you to avoid contact with its poop (which you should be doing anyway). We don't treat Salmonella carriers - dogs that are healthy and shedding Salmonella will eliminate it on their own, usually within a couple weeks. A negative result also doesn't guarantee that the dog is truly negative. Usually we want multiple negative cultures to rule out Salmonella since it can be shed intermittently and can be hard to detect.
My dog is healthy but has been fed recalled food. Should he/she be treated with antibiotics?
NO. That's the last thing I want to do. Antibiotics are not very effective (or effective at all) at eliminating Salmonella that's living in the intestinal tract. A healthy animal shedding Salmonella is an indication that the body is handling it. It doesn't mean that disease won't occur, but one critical aspect for preventing intestinal infections is the protective effect of the gut microbiota - the trillions of bacteria that are in the gut helping suppress "bad" bugs like Salmonella. My concern with prophylactic treatment is that we might make things worse by suppressing this protective bacterial population and letting Salmonella overgrow in a situation where it otherwise would not have been an issue.
Fox / dog / human, North Carolina
In this case, a rabid fox had a "direct encounter" with several people, then it was killed by a dog. Three people have started post-exposure treatment.
- The article states that the dog was vaccinated against rabies, which is good to hear. However, it goes on to say that exposed pets need to be euthanized or have a 6 month quarantine. In reality, standard guidelines are that unvaccinated pets are treated like this while vaccinated pets undergo a less rigourous 45 day observation at home. Hopefully the discrepancy is simply due to inaccurate reporting and not misinterpretation of guidelines by local officials.
Cat / human, Maryland
A rabid stray cat scratched five people, who have been urged to undergo post-exposure treatment. Officials are calling for anyone who potentially had contact with this cat go to an emergency room.
- However, odds are if someone goes to an emergency room and says they might have had contact with this cat, they're just going to sit around until someone tells them they don't know what needs to be done, or to go home and deal with someone else. Rabies exposure is a medical urgency, not an emergency. People should take a little extra time to work with their physician and/or public health rather than go to the emergency room.
- People who may have had contact with the cat need a proper assessment to determine if they were potentially exposed to rabies, since just being around the cat or having casual contact is not a risk. Scratches are a bit controversial since they are low risk for rabies transmission (unless the scratches become contaminated with saliva from the animal), and there are conflicting guidelines regarding what to do for a person who is scratched.
- This is also a good reminder to stay away from stray cats.
Fox / human, Pennsylvania
In this report, authorities are trying to find a person that cradled an injured fox in a blanket. The fox was subsequently identified as rabid and they need to determine whether the person was potentially exposed to the virus.
- Again, another reminder to stay away from wildlife, and if there is contact with wildlife, make sure rabies exposure is considered.
Bat / human, Indiana
A student was bitten by a rabid bat while he slept in an Indiana University dorm room. He woke up after being bitten (good thing, since he probably wouldn't have noticed otherwise due to the often tiny marks left by a bat bite). He is now receiving post-exposure treatment.
Rabies isn't going away, at least any time soon. People need to be aware of the risks in rabies-endemic areas, take care around wildlife and vaccinate their pets.
Photo credit: Rob Lee (click for source)
After starting off like a simple recall of potentially Salmonella-contaminated dry pet food, the Diamond Pet Food problem has now expanded into a multistate outbreak of salmonellosis in humans linked to exposure to the contaminated pet food. At last count, there were 14 affected people from 9 US states, including 5 who required hospitalization. These numbers could increase since so far they only include people who got sick up to April 1 (because it takes time for Salmonella to be grown in the lab, sent to CDC for testing and the result investigated, later cases may not have been reported yet).
This outbreak involves Salmonella Infantis, a strain that is uncommonly identified in people. Finding an increased number of infections caused by an unusual strain makes it easier to identify an outbreak, as was presumably the case here. This strain has also been isolated from various types of pet food that were produced at the Diamond Pet Foods' South Carolina plant. Despite the name, this strain of Salmonella is not more likely to infect infants, and people ranging from less than 1 year to 82 years of age have been infected.
Details about the types of contact people had with the pet food are limited. 70% of infected people reported having contact with a dog the week before getting sick. How the other 30% could have been exposed is unclear. Sometimes peoples' recall is poor, especially if they had transient contact with a pet. Individuals could have been exposed from environmental contamination when visiting a household where contaminated pet food was fed, without having direct contact with a pet. It's also possible some cases are not directly related to the outbreak and co-incidentally were exposed to the same strain from some other source.
Since we see periodic outbreaks associated with dry pet food, does that mean that other types of pet food are safer? Not really. Canned food is ultimately the safest because of the heat processing, but it's not practical for all animals.
Typically, after a report like this, I get a barrage of emails from people saying "See... we don't have large outbreaks from raw food diets so they are safer." Unfortunately, that's not the case. High pressure pasteurization (HPP) of raw food, a process that uses pressure with minimal heat to kill bacteria, is an effective method for reducing contamination of such products with harmful pathogens like Salmonella, and HPP is now being used by a couple of companies. These raw diets should be quite safe from a Salmonella standpoint. Otherwise, the risk of Salmonella contamination of raw pet foods is still very high, and if anything, the dry food outbreaks show how people can be infected from contaminated pet food.
Why don't we see large outbreaks associated with raw food? Outbreaks get detected because certain patterns or unusual findings are identified. Raw pet food associated outbreaks probably occur but are not as readily identifiable since raw meat contamination is common but involves variable Salmonella types that regularly change. In a situation like that, you can potentially have lots of people getting Salmonella from raw food, but if there is limited commonality in strains and products, it doesn't get picked up as an outbreak. That's particularly true when the strains that are involved are the common ones found in food, since they would often be dismissed on the premise that the person likely got it from some unknown food source. Without large numbers of cases in an area or a cluster of unusual strains, the investigation wouldn't likely get very far and nothing would be reported.
How do reduce the risk of getting Salmonella from pet food (or your pet)?
- Don't feed pets in the kitchen. This practice has been associated with an increased risk of disease in a previous outbreak of salmonellosis in children.
- Wash your hands after handling pet food.
- Don't let young children have contact with pet food.
- Use common sense when handling pet feces.
More information about both Salmonella and issues pertaining to raw diets (including how to reduce the risk) can be found on the Worms & Germs Resources - Pets page.
Recently, I've had a run of interesting advice calls about strange infectious diseases in dogs that have been imported from various countries. At a meeting the other day, I had some discussions with colleagues from across Canada who have also seen various infectious diseases in imported dogs.
Imported infectious diseases are a concern for a few reasons:
- Some could spread to other dogs in Canada.
- Some could infect insect vectors and eventually establish themselves in Canada.
- Some could pose a significant risk to people (e.g. rabies).
- Diagnosis of foreign diseases in pets can be difficult because Canadian vets may have little knowledge about them, and they just don't come to mind when evaluating a sick animal.
Some of these sick imported pets are animals adopted by people when traveling. Some arrive via organized rescue programs, both from the US and beyond (we'll leave the discussion about the ethics and economics of importing stray dogs from different regions when we have no shortage of them here for later).
One thing that strikes me as bizarre is how easy it is to import a dog from any country. I do a fair bit of international research and regularly import samples like nasal swabs and fecal samples from different countries, and it's more effort for me to get a nasal swab into the country than it would be to bring in the whole dog.
For example, if I want to get nasal swabs from dogs from a different country to test them for staphylococci, I need to:
- Submit an import permit request to the Canadian Food Inspection Agency (CFIA) (and pay).
- Submit a facility certification form to the CFIA signed by our Biosafety Officer.
- Submit an import permit request to the Public Health Agency of Canada (PHAC).
- Have a facility compliance letter from PHAC that's based on a long questionnaire demonstrating that I have adequate facilities, protocols and training, along with a facility inspection by our Biosafety Officer.
For me to import a dog, I need:
- Proof of rabies vaccination
That's it... unless I want to import a dog less than 8 months of age and not accompany it into the country, in which case I also need a health certificate (which in itself is not much of an indication that there's limited risk of infectious diseases).
Does that seem logical?
Identification of the strain of rabies in the first person in Toronto to be diagnosed with rabies in the past 81 years has essentially confirmed that the infection was acquired abroad. Toronto Public Health has indicated that the strain obtained from the infected man is one known to circulate in dogs in the Dominican Republic, where the man had been working over the past few months.
Little additional information is being released, including whether the patient is alive (and if so, what his condition is). As part of the typical rabies investigation, 15 healthcare workers and an unknown number of family members and friends have been deemed to have been potentially exposed to rabies from the man and have been offered post-exposure treatment. The risk of human-human transmission is exceedingly low, but given the severity of disease, the logical approach is to err well on the side of caution when considering post-exposure treatment.
While rabies strain typing supports a dog bite as the source, that can't be confirmed at this time since the man was too ill to provide any information by the time rabies was being investigated. Sometimes, exposure is determined indirectly based on information from friends and family (e.g. the person mentioning that he was bitten by a dog) and presumably there is an effort to question people who had contact with the man in the Dominican Republic to try to piece this story together.
A group of flea (or flea and tick) collars have been removed from the market in France following a risk assessment. The review looked at these widely available, over-the-counter products that contain a variety of different chemicals. The determination was that the risks posed by contact with the collars (particularly to children) were unacceptable compared to the benefits.
As with most risk assessments, cost-benefit is the key. With flea collars, you have something containing a chemical that's easily (and commonly) touched by people, and you also have the potential that young children could put them in their mouths. That's the "cost" aspect. The beneficial side is two-pronged. One consideration is the importance of flea and tick control to human and/or animal health. That's certainly significant, since fleas and ticks can be associated with various problems, including infectious diseases and flea allergies. However, the other consideration is whether there are safer and/or more effective alternatives. The answer to that is yes - there are now much better approaches for flea and tick control than flea collars in terms of effectiveness and safety. The disadvantage is that these alternatives are somewhat more expensive and not available over the counter, but the cost and logistics are far from cumbersome.
So, the withdrawal of the flea collars from the market in France is a very reasonable move, and one that needs to be accompanied by information to pet owners that emphasizes that:
- yes, flea and tick control are still important.
- there are much more effective options that are safer for the pet and the family.
- people should work with their veterinarian to determine the approach that best fits their pet(s) and family.
It's amazing how one little email comment can make a mess of my week.
Here's the story: I sent an email to a colleague that works for an agency in Ontario. At the bottom of the email, I gave an FYI about an Ontario dog that was found to have antibodies against canine flu, but that wasn't sick. At the time, I didn't realize that my colleague was no longer at the aforementioned agency.
- Astoundingly, instead of cancelling my colleague's email account, the agency had left the account active - and the CEO of the agency reads her emails!
- In this case, not only does the CEO read the email, she forwards it to other people in the agency.
- Not only do the others read it, they create a release that they send out to associates of their agency throughout the province and some other groups... without contacting me to get details, understand the full story or get permission to use the information I provided. Not exactly a good communications strategy.
In an amazingly short period of time, I was contacted by two provincial Ministries about Ontario's canine flu status, since incomplete information was forwarded to them, and veterinary clinics in the province are now asking questions about our "canine flu case" or "canine flu outbreak."
So, to set the record straight (and decrease the number of phone calls I'm getting today):
- We found a dog that had antibodies against canine influenza as part of an outbreak investigation. The outbreak was not caused by canine flu.
- The dog had the same antibody level on two blood samples taken two weeks apart. This is not consistent with disease caused by flu. Rather, it indicates that the dog has been exposed to the virus.
- The fact that the dog has been exposed to the virus is noteworthy. The only other seropositive (i.e. antibody positive) dog that we have seen in Ontario was a greyhound from Florida, and we assumed it was infected in Florida. That was a few years ago, and we haven't seen anything since. Initial information indicates that this dog has not left the province, but I'm working to confirm that before I can be confident that this is evidence that canine flu is present in Ontario.
This is an important topic because if/when canine flu hits a region, it certainly has the potential to cause big outbreaks. The outbreak at a Texas racing facility that I wrote about yesterday is a good example of the bad things that can happen when flu hits a susceptible population. Knowing if the virus is in the area is important for things like vaccination programs and making recommendations for management of respiratory disease cases in veterinary clinics and in the community.
We currently have no evidence of canine flu activity in Ontario, but we are actively looking because we assume that it will make it here sometime, if it's not here now. Identifying it early and communicating that properly are critical control measures for canine flu and other emerging infectious diseases, but there's nothing to worry about at the moment.
As canine influenza continues it's rather gradual, patchwork movement across North America, an outbreak at a greyhound racetrack southeast of Houston highlights some of the concerns about this virus. Canine influenza has been active in the Houston region for some time, causing sporadic infections as well as outbreaks in pet dogs in the community and in veterinary clinics.
Greyhound tracks are a great place for influenza transmission because they have a lot of dogs in close quarters, and racetrack outbreaks can be large and severe. In this outbreak, approximately 100 dogs have been affected so far, with six deaths. It sounds like there are 600-700 dogs on the track, and given how transmissible the virus is, unless they have very tight infection control practices in place to separate groups of dogs (unlikely), it's reasonable to assume that many more dogs will be infected, or have already been infected but weren't recognized because they had mild disease. The ~6% mortality rate is not surprising, as dogs can die from severe influenza or because of bacterial pneumonia that develops afterwards. Higher death rates are talked about, and were features of the early reports of canine flu in Florida, but this lower rate seems to be more typical.
Local Humane Society personnel are rightly warning pet owners to be on the lookout for canine flu. Public awareness is critical, although I'd argue with some of their advice:
"The only protection is the dog flu vaccine."
- Not really. It's part of the infection prevention plan but not the only thing. Vaccination is an effective way to reduce the incidence or severity of disease, but it's not 100%. Vaccination should be considered the last line of defense that comes into play when efforts to avoid the virus have failed. If the dog doesn't get exposed to canine flu, it won't get influenza, regardless of vaccination status. Dog owners need to be aware of high-risk situations and avoid contact with dogs that are or have recently been sick. That being said, in an area where canine flu is active, vaccination is a good idea, since you can never completely guarantee your dog won't be exposed to the virus if it's exposed to other dogs.
"Dog owners were warned if they noticed any flu-like symptoms in their dog to take them to a vet immediately for antibiotics and the vaccine and not to take their dog to the park or doggie daycare."
- I agree with the last part. If your dog is sick, keep it away from areas where other dogs mingle while it's sick and for about 10 days after it gets better. So, if that's the case, why take all potentially sick animals into the vet right away? It might just result in exposure of other dogs to the virus. If you have influenza and you're not very sick or at high risk for complications, the recommendation isn't to immediately go to the doctor. It's to rest and stay away from other people. The same applies for dogs.
- Calling a veterinarian to see whether the dog should be examined makes sense. This also helps ensure that if the dog does go to the clinic, it can be handled properly. By that, I mean instead of showing up, checking in at the front desk and lingering in the waiting room with other dogs for a while, a dog with suspected flu should be admitted directly into isolation or an exam room. This can be done by calling the front desk on arrival or by checking in without the dog, so that the dog can be taken directly to a contained area to avoid other dogs.
- Antibiotics are rarely needed. Antibiotics don't kill influenza virus, so they are indicated only if there is evidence (or very high risk) of secondary bacterial disease, which doesn't happen in most cases. We don't want every coughing dog on antibiotics, since few need them.
A few months ago, I wrote about an article that appeared in the journal Orthopedics. It was a very bad article that blamed a person's infection on "excessive contact" with pets, with no evidence that the pets were involved (and no evidence that dogs have ever been found to carry the bacterium in question).
Here's the Letter to the Editor that was just published.
I was surprised to see the article “Pyogenic cervical spondylitis caused by Pasteurella haemolytica attributed to excessive contact with dogs” by Machino et al. 1 The authors stated that Pasteurella haemolytica (which was renamed Mannheimia haemolytica over a decade ago) is a common inhabitant of the oral cavities of dogs and cats, citing prevalence rates of 71% to 90% in cats and 21% to 60% in dogs. However, they provided no references for these prevalence data, and I am unaware of any studies that have found this bacterium in the oral cavities of dogs, let alone at such high rates. The authors cited 3 articles as supporting zoonotic infections with this organism, yet these 3 articles all involved other Pasteurella species. Pasteurella multocida, a completely different bacterium, is a common oral commensal in dogs and cats and has been reported frequently as a cause of pet-associated infection. The authors may have confused these markedly different organisms. The authors also stated that the recent increase in pet ownership has caused an increase in P haemolytica infections from bite wounds, with no evidence supporting an increase in infections caused by this bacterium or the role of pets in human P haemolytica infections. Although zoonotic infections are problematic and it is important to consider the potential role of household pets in human disease, this article is highly flawed, and retraction should be considered.
J. Scott Weese, DVM, DVSc, DipACVIM
Guelph, Ontario, Canada
The authors either didn't get any of the points I made or didn't care and wrote a rather evasive response.
We thank Dr Weese for his letter. We reported a rare case of Pasteurella haemolytica as the pathogenic bacteria behind pyogenic cervical spondylitis. We searched the literature for reports on spondylitis caused by P haemolytica to the greatest extent possible, but it seems that the present case was the first.
In the present case, a needle aspiration biopsy was performed under diskographic guidance, and P haemolytica was detected on bacterial culture. We believed that this case was caused by P haemolytica. Because the patient owns 2 dogs and frequently kisses them on the mouth, this excessive contact was believed to be the cause of infection. No other causes were evident in this case. Although we cannot declare that it is the cause, no evidence was found that it was not the cause.
Our main point in the article was that osteomyelitis has been reported in the field of orthopedics, and, keeping in mind the fact that pyogenic spondylitis is also caused by rare bacterium, we believe it is important to engage in routine treatment regimens.
Masaaki Machino, MD
Anyway, the point wasn't to make the authors look bad. It was to remind people that we need to consider pets as sources of infection but do so in a logical manner, and simply blaming the pet when there's no evidence doesn't do anyone any good.
As we've discussed previously, rabies has been a big problem in Bali since 2008. Previously rabies-free, this densely populated island has been struggling with a large and persistent canine rabies outbreak that has resulted in numerous deaths and much debate about control measures.
- Dog bites are very common on the island, with a daily average of nearly 100 bites reported over the study period. Since many bites don't get reported, even this large number is an underestimate.
- The average age of affected people was 36 years, with a range of 3-84 years. All 104 died.
- Most of the cases (57%) were male. This is common, although whether it is because men are more likely to be bitten (because of greater exposure or greater provocation) or less likely to seek medical care after a bite is not known.
- There was a history of a dog bite in 96/104 infected people. It's likely a bite occurred for the others as well, but in those cases the patient was unconscious at the time rabies was suspected and family members did not know of any bites.
- The incubation period ranged from 12 day to 2 years. It was less than 1 year in 98% of cases. Very short incubation periods, like the 12 day one reported here, are almost always associated with bites to the head or neck, since it's a shorter distance for the virus to travel up nerves to the brain.
- Early signs of disease are often vague. Pain or numbness at the location of the bite (37%), nausea or vomiting (30%), fever (22%), aches (17%), headache (16%) and insomnia (7%) were most common.
- 81% of people that developed rabies did not undergo any type of treatment. 11% washed the wound themselves. Only 6% went to the hospital on the day of the bite. The people who went to the hospital received a course of rabies vaccines but did not receive rabies immunoglobulin (RIG, which is anti-rabies antibodies). So, while they were treated, they didn't get the full recommended treatment. This is incredibly frustrating since rabies is almost 100% preventable if people get proper medical care. Failure of most of these cases to even seek care is a huge issue, and inadequate treatment of people who sought medical care compounds the problem. Not all of the vaccinated people completed the full vaccine course before developing signs of rabies. These were individuals who had short incubation periods because of bites to the head and neck.
These results are not surprising but demonstrate a few important concepts, including:
- the need for education of the general public to seek medical care after a bite.
- the need for proper education of healthcare providers so that people who are bitten get proper medical care.
- the need for adequate supplies of rabies vaccine and immunoglobulin. It wasn't stated whether people didn't receive RIG because it wasn't offered or (as is common in some regions) it wasn't available.
- rabies may not be considered initially when signs first start appearing, as many of these people ended up being treated for various other potential problems before rabies was considered. While rabies is almost always fatal, there have been very few "successfully" treated individuals (meaning they didn't die, but they can still have long-term neurological impairment), but to have any chance at success, treatment needs to be administered as quickly as possible.
- control of canine rabies is a key part of controlling human rabies.
Max, a 12-year-old Chihuahua from Greenfield, New Jersey, was euthanized recently after he was exposed to rabies. While far from unusual, the case highlights the ongoing risk of rabies exposure as well as issues with understanding of rabies guidelines and communication.
Max was attacked by a rabid raccoon - an ever-present risk for animals that go outside (or get outside) in many regions. Animal control was called and the raccoon was caught. It was euthanized and rabies was confirmed, indicating that Max was very likely exposed to the virus.
Here's where things seem to get strange. The paper reports:
"Once exposed to a rabid animal, a six-month quarantine is required for the exposed animal, even those animals that have been inoculated with a rabies vaccine."
- Not really. In Canada, standard guidelines are for a 6 month strict quarantine for dogs (and cats) that are not properly vaccinated, but only a 45 day observation period is required for vaccinated animals. I don't know if in this jurisdiction they made up their own different rules, whether someone doesn't know what's supposed to be done or whether it's poor reporting, but it's a concern because it can be a difference between life and death... not necessarily from rabies, but from the quarantine requirements alone. People are often unwilling to undertake a strict 6 month quarantine and choose euthanasia (as was the case here), while the 45 day observation period is much more acceptable.
The attending veterinarian stated "Because of the way it was exposed and because of the positive, I think there was a really good chance this dog was going to get rabies".
- It's certainly possible, and nowhere does it say whether Max was properly vaccinated. However, there's a reason we vaccinate. It's a highly effective vaccine and we're trying to prevent disease. Nothing's 100%, but with proper vaccination, the risk of rabies is greatly reduced.
It's also stated that "due to the nature of rabies, until behavioral changes occur, the animal is not infectious".
- While this doesn't have anything to do with Max's situation, it's not true. Animals can shed the virus for a short period before they show signs of illness. That's the reason there is supposed to be a 10 day quarantine period after a dog bites someone - to see if the dog develops signs of rabies (which would have major implications for the person who was bitten).
Curiously, the article ends with a reminder to vaccinate pets, which seems kind of strange if their assumptions are that an exposed animal will get sick irrespective of vaccination status and that vaccination will have no impact on what happens to an animal after exposure.
However, despite the miscommunication, the take-home message emphasizing the need for vaccination should be heeded. As well, people making decisions about what to do after rabies exposure should make sure they do so based on the best evidence that's available, namely the Compendium of Animal Rabies Prevention and Control.
We've had a really bizarre spring around here. At a time of year when we're usually bouncing back and forth between snow and rain, we seem to have skipped over spring and moved right into summer. It was 25 C (77F) today, the snow's long gone, frogs are deafening at night and, on the bad side, mosquitoes are swarming at dusk.
This has led to a lot of questions about the implications of the weather on the regional approach to heartworm prevention, since the typical approach is to start treatment in early June. Specifically, does the early spring mean that there's increased risk from this mosquito-borne parasite or that we need to start treating dogs earlier?
Dr. Andrew Peregrine, a veterinary parasitologist at the University of Guelph, has taken a break from fielding calls about this subject to provide some insight.
A big question is whether over-wintering infectious mosquitoes are a concern.
If over-wintering mosquitoes aren't a concern, which is a leading consensus, then the mosquitoes we're seeing now are newly hatched.
- If that's the case, they have to feed on an infected animal and the parasite has to mature inside the mosquito before the mosquito poses a threat to dogs (and less commonly cats, and very rare humans).
- With the current temperatures, it should take at least three weeks for this to happen. Therefore, if a mosquito hatches in March and happens to feed on an infected animal, it would be into April before it's infectious. Heartworm preventive medication has 'reach-back' activity of at least 7-8 weeks, meaning that the medication will effectively prevent disease from exposure at least 7-8 weeks prior to treatment.
- So, if a mosquito promptly feeds on and infects a dog after it becomes infectious, heartworm medication given at the beginning of June would still be effective at preventing disease because of this reach-back period.
- In this scenario, there's no need to start treatment any earlier around here than the traditional June 1 start date.
There are some people who think that overwintering infectious mosquitoes are an issue, although evidence supporting that seems to be lacking. If overwintering infected mosquitoes are an issue, the mosquitoes that are around now might be infectious.
- In that case, June 1 might be too late in the event of an early exposure, and May 1 would be a more appropriate start.
Bottom line, there is no answer that's 100% certain since we don't have all the information that we need. June 1 is most likely perfectly fine. Anyone who's's ultra-concerned could start treatment on May 1. There's no real downside (apart from a little extra cost) of this extra treatment, but it's probably not necessary.
The Ontario Ministry of Natural Resources and Welland SPCA are warning people about an apparently large number of cases of distemper in raccoons in the area. Distemper is a pretty nasty disease which can be spread between dogs and wildlife. It’s caused by canine distemper virus, but the "canine" part of the name can be a little misleading, since this virus readily infects some other species such as raccoons.
In addition to the problems with sick and dying raccoons caused by the outbreak, there are two main concerns for pet dogs:
One concern is the potential for wildlife to transmit canine distemper virus back to dogs. It’s hard to say what the risk of that is, and the risk would be primarily to young dogs that are not adequately vaccinated. If a dog has an encounter with a raccoon that is sick with distemper, it’s possible the pet could be exposed to the virus. Dogs are also probably more likely to have close encounters with sick raccoons that are unable or unwilling to run away, as opposed to healthy raccoons. If an inadequately vaccinated dog gets exposed, it can get very sick, which is obviously bad for the dog, and also creates another potentially infectious animal to keep passing the virus along.
The other concern is differentiating distemper from rabies. Distemper can cause signs that are very similar to rabies. If a dog has an encounter with a raccoon that is behaving abnormally, rabies is a big concern. If a dog is exposed and the raccoon is not available for rabies testing, the dog would require a 6-month strict quarantine or euthanasia if it's not vaccinated (or not adequately vaccinated), or a 45 day "observation period" (on a proverbial tight leash) if vaccinated. These measures aren’t easy to implement, and unvaccinated dogs often end up being euthanized because owners don’t want to go through the hassle of a 6 month quarantine.
What does this mean to the average pet owner? Well, nothing that they shouldn’t be thinking about anyway. This just increases the relevance of some routine measures such as:
- Keeping dogs that are outside are under control so they don’t encounter wildlife.
- Ensuring dogs are properly vaccinated against distemper and rabies.
- Taking particular care to prevent exposure of young unvaccinated dogs to wildlife.
- Discouraging raccoons from taking up residence in yards.
Nothing earth-shattering, but these basic precautions can greatly reduce the risk of disease transmission from wildlife to dogs, be it rabies, distemper or other bad bugs.
An interesting and frankly somewhat scary report in an upcoming issue of Veterinary Microbiology (Clegg et al 2012) provides further information suggesting that cats might be a source of canine parvovirus infection. This potentially fatal infection, which typically affects young unvaccinated (or inadequately vaccinated) puppies, is a major problem, and outbreaks occur (not uncommonly) in some high-risk populations like shelters.
In the 1970s, a new form of canine parvovirus, CPV-2, emerged and rapidly spread worldwide. That predates my veterinary career but I've heard stories of clinics where you couldn't turn a corner without stepping on a dog that was hospitalized for treatment of parvo, since it was a new disease and vaccines were not yet available. CPV-2 was shown to be able to grow in cat cells in the lab, but not in live cats, so it was generally assumed that dogs had CPV and cats had their own closely related virus, feline panleukopenia virus (FPLV). However, new variants of CPV-2 have emerged over time, and these seem to have a greater ability to infect cat cells in the lab, and disease caused by these strains has been reported in cats both experimentally and in limited real-world situations. However, it was still considered an uncommon event and the role of cats in parvovirus infection of dogs was largely thought to be inconsequential.
Or maybe not.
In this new study, researchers collected fecal samples from 50 cats in a cat-only shelter, and 180 samples from 74 cats at a shelter than housed both dogs and cats. Canine parvovirus shedding was identified in 33% of cats from the cat shelter and 34% of samples from the dog/cat shelter. A concern with a study like this is cross-reaction of tests for CPV and FPLV, but they went a few steps further to confirm that the virus was indeed CPV, not its feline relative. They also showed they could grow the CPV from fecal samples in cells in the lab, which means they were detecting live virus in the animals, not just dead viral bits working their way through the cats' intestinal tracts.
The results are interesting and concerning, since they showed that a pretty large percentage of cats in some situations could be shedding live CPV, making them a potential source of infection for dogs (and possibly other cats).
What makes this even more concerning is the duration of shedding that they identified when they collected samples from the dog/cat shelter over time: cats shed the virus for up to 6 weeks, despite appearing healthy.
This raises concerns about the potential role of cats in the spread of CPV. Cats and dogs don't tend to mix much in parks or outside, but CPV is a very tough virus that can survive for a long period of time in the environment. It's certainly plausible that cats could be depositing CPV-laden feces in the outdoor environment, and since the virus can survive the outdoor exposure and some dogs are notorious poop-eaters, it's a route of transmission that can't be dismissed. Cross-contamination within shelters is also a concern.
The true role of cats in canine parvovirus infection isn't known and it's probably quite limited compared to dog-to-dog spread. However, this study shows that we at least need to be thinking about it and considering cats when dealing with parvovirus problems in shelters and households.
Some things to think about:
- Young puppies should be kept away from cats, especially strays and cats from shelters, until they are properly vaccinated.
- Parvo is one more reason to have good physical and procedural separation between cats and dogs in shelters.
- If a parvo outbreak in underway in a facility, prevention of potential cross-contamination from cats is required.
- If a cat has been in contact with a dog with parvo, it should probably be considered potentially infectious and kept away from susceptible dogs for at least a few weeks.
- Canine parvovirus vaccination is highly effective in dogs. If a dog is properly vaccinated, the risk from cats (or other dogs for that matter) is minimal.
While rare, Morocco continues to be a source of rabies in European animals. The latest case involved a puppy imported into the Netherlands. The (somewhat) brief version of what happened goes like this:
- On Jan 28, 2012, a Dutch couple bought an 8-week-old puppy in a parking lot in Morocco. The puppy was taken to a local veterinarian, microchipped and given a certificate of good health. It would have been too young to vaccinate against rabies.
- On Feb 4, the couple travelled from Morocco to Spain by car and ferry. They then obtained a European pet passport from a Spanish vet, despite the fact that the dog was not vaccinated against rabies (an EU requirement for a pet passport).
- On Feb 11, they returned to the Netherlands. Customs officials "cuddled" with the puppy but apparently didn't ask about rabies vaccination. When they got home, the couple exposed the puppy to many family and friends.
- On Feb 14, the puppy started to become aggressive. They contacted a veterinary practice, and it was assumed the problem was stress, so a sedative was given. (It's not clear whether the puppy was actually examined. If not, that's a pretty big mistake.)
- On Feb 15, the puppy was uncontrollable. The report states "When they realized that the puppy originated from Morocco, the veterinarians contacted the Netherlands Food and Consumer Product Safety Authority (NVWA)." The puppy's history should have been a basic question asked when the couple first contacted the veterinary practice about the animal. Regardless, the concern about rabies came to the forefront with that information, and the puppy was euthanized. Rabies was confirmed that evening (a pretty impressive turnaround time for rabies testing).
- As is typical, an investigation was launched, and a search for people who had contact with the puppy during the period when it was potentially infectious was started. That's not easy when it involves multiple countries, as was the case here, since the potentially infectious period is 10-14 days prior to the onset of clinical abnormalities. The potential contacts included the Moroccan veterinarian, some friends in Spain, the Spanish veterinarian, three customs officials, a couple of unknown people in a Spanish restaurant and at the Malaga airport, and 43 people after arrival in the Netherlands (plus an unknown number of people who petted the puppy on the street).
- Contact doesn't mean exposure, since rabies isn't transmitted by casual contact, so the type of contact was queried further. The risk is from bites or contact between the dog's saliva and broken skin or mucous membranes (e.g. mouth, eyes). Because of concerns that kids don't accurately recall the type of contact they have (meaning they might fail to mention a little nip or some other high risk contact), all nine children who had contact with the puppy were given post-exposure prophylaxis. The Dutch friends in Spain reported high risk exposure and were also treated, however they had to return to Amsterdam for full treatment since anti-rabies immunoglobulin (antibody) was not available in Spain. Information was provided to Moroccan officials but information about what happened there wasn't available.
- Overall, it is stated that 45 people needed post-exposure treatment (although who those 45 were isn't really clear). That's a pretty large exposure, resulting is much angst and expense.
- Two cats and a dog were also exposed to the puppy. The dog had been vaccinated, and received a booster. (It would also be standard protocol to quarantine them for 45 days as well, but that's not stated.) The cats were euthanized because a "suitable quarantine place was not available," a rather strange statement since quarantine isn't a very high tech procedure.
Obviously, this is of relevance to people that live in Morocco or are going to get a dog from Morocco. Those people need to be aware of rabies, be careful when getting a pet, ensure their pets are properly vaccinated against rabies and be careful around stray animals. This report also highlights a couple of other issues:
- A parking lot isn't a good place to buy a puppy, for many reasons. A reputable breeder isn't going to sell a puppy there, and there are lots of good, well-evaluated puppies available through good breeders and shelters.
- Pet importation requirements are pretty weak in a lot of ways, especially if no one actually pays attention to them. That seems to be a recurring theme as well with these imported rabies cases. Here, the puppy was given a European dog passport without the required rabies vaccination, and was not kept in quarantine after arrival. It also went through no less than three customs points in transit, where no one queried rabies vaccination status. The mandatory 3 month quarantine would have prevented exposure of most of the people that required post-exposure treatment.
- Visitors to areas where rabies is endemic in the dog population need to be aware of it. Encountering stray dogs isn't exactly rare in many countries, and while staying away from strays is a good general rule everywhere, people should be particularly careful in areas where the risk of rabies is high. Travelers also need to be aware of what to do if they are bitten by a stray animal.
Kennel cough, also (and more properly) referred to as canine infectious respiratory disease complex (CIRDC), has been in the news lately. This condition is a syndrome, not a specific disease, being potentially caused by a range of bacteria, viruses and Mycoplasma, including canine parainfluenza virus, canine influenza virus, canine respiratory herpesvirus, canine adenovirus, distemper virus, Bordetella bronchiseptica and Streptococcus zooepidemicus. Regardless of the cause, it's still a highly infectious disease characterized by a hacking cough. Serious illness, including deaths, can occur but is uncommon.
Here are a couple of kennel cough issues have hit the press lately:
- Mandatory kennel cough vaccination is now required for dogs competing in the Iditarod Trail Sled Dog Race. It's easy to see how this disease is a concern in these sled dogs, given the stress and rigours of competing and the mixing of many dogs from different areas. Kennel cough vaccination doesn't prevent all cases, since it only protects against Bordetella bronchiseptica +/- parainfluenza virus, but it's a useful infection control tool in high risk populations. The requirement has been implemented in part due to cases of kennel cough that were encountered in the 2011 race, along with the publicity that was generated (including the attention of PETA).
- In Rocklin, California, a dog park was closed for two days because of a kennel cough outbreak. It seems the closure was in response to the diagnosis of kennel cough in two dogs, and it's an unusual move given the apparently low number of cases. The issue isn't the park environment itself being biohazardous - rather, the park provides an opportunity for dog-dog transmission. Given that, it's a questionable control measures since it's unlikely that people will keep their dogs at home. Rather, they'll probably just go to another park, where the same risks will be present. It's a bit like the debate around school closures with pandemic influenza. On the surface, it seems like a good idea, since kids won't pass around flu at school. However, in reality, what happens is kids congregate at the mall and other places if schools are closed, so it just moves the site of transmission somewhere else and probably doesn't have any net benefit. Here, a better response would probably be an educational campaign to get people to keep sick dogs at home, have people keep their dog away from other dogs at the park and encourage vaccination of high risk dogs (which would include those that go to a park and interact with other dogs).
- A kennel cough outbreak was reported in Bozeman, Montana, with veterinarians asking owners to be on the lookout for disease. Local veterinarians reported a spike in the number of cases, with one clinic reporting around 20 cases in the past month, which is a pretty remarkable number for your average vet clinic.
- And locally... nothing specific, but I keep getting reports of clusters of respiratory disease in dogs. We often don't get a chance to investigate small clusters to figure out the cause, since information often gets to me after the fact, but it's a recurrent problem in Ontario. Most of the reports are rather poorly defined clusters of sick dogs, with occasional severe outbreaks involving fatalities (including one I'm dealing with at the moment).
The parents of a US soldier who died of rabies after being bitten by a dog while deployed in Afghanistan want their son's superiors to be held accountable. Specialist Kevin Shumaker died last August, eight months after being bitten by a dog. An Army investigation concluded that he died because members of his unit ignored rules prohibiting keeping pets (they were befriending feral dogs) and that he didn't seek treatment or notify the chain of command after being bitten. His parents feel that their son is being falsely blamed and that people who should have known better didn't do their jobs. It's a complex issue with some interesting questions.
What should the average soldier know about rabies?
It should be assumed they know absolutely nothing to start off, and a risk assessment should be performed for each deployment to determine what they need to know. When they are being deployed to a rabies-endemic area, they need to learn to stay away from dogs and report dog bites promptly, and why.
Whose job is it to report a bite?
At the end of the day, everyone has to be their own advocate and make sure they report any possible rabies exposure. People up the chain of command don't see everything and individuals need to protect themselves. However, once the bite is reported, others have to act. That might be the breakdown here.
Was anyone actually notified?
The Army's investigation actually documents the fact that Spc. Shumaker notified other personnel at least twice. One was a veterinary corps officer and the other was the person doing his post-deployment health screening. Here's where the ball was probably dropped. Every veterinarian knows about rabies. A veterinarian working in a rabies endemic region is certainly aware of the risks and has a responsibility to act on a reported bite. I find it astounding that a veterinarian in this situation wouldn't initiate a response, particularly given the fact that (at least in my limited experience) the US Army Veterinary Corps has some excellent veterinarians, so this seems rather strange. Further, what's the purpose of a post-deployment health screening if health issues that arise are ignored? If the person doing the health screening didn't understand the concerns about rabies, he or she was inadequately trained and shouldn't have been doing the job. If the screener was properly trained and didn't report it, he or she was incompetent, plain and simple.
Would anything have changed the outcome here?
Absolutely. Rabies is almost 100% fatal, but it's almost 100% preventable when post-exposure treatment is given before the onset of disease. There was lots of time in this case between the bite and when the soldier became ill, and if he had been treated following one of these reports, you can almost guarantee he would not have developed rabies.
Whose fault is this?
Well, everyone plays a role here. The soldier ignored the animal contact rules. Superior officers on base presumably ignored the fact that they were ignoring the rules, probably not thinking about the possibility of rabies, and seeing the positive effect on morale of interacting with the dogs. If the veterinary officer and post-deployment health screener were told about the bite and did nothing, they played a huge role since they, of all the people in this chain, should have known better.
What should happen here?
Rather than fighting over who's to blame (the usual response), an investigation should figure out why this happened and how to prevent it from happening again, largely via better training and clear expectations of personnel.
Hopefully that's happening, since Deputy Commanding General Maj. Gen. William Rapp recently approved a series of recommendations, including:
• Further investigation to see if any members of the unit should be disciplined for their actions or omissions during the unit’s deployment to Afghanistan
• Institute an animal-borne disease surveillance program, standardize rabies vaccine requirements and improve dog bite reporting requirements (I'm surprised that wasn't already the case)
• Reinforce animal bite and rabies training for veterinarians and post-deployment health screening staff
An article from NBCMontana.com describes a kennel cough outbreak in dogs in Bozeman, Montana. It's a pretty basic article that outlines a rather typical presentation of kennel cough (now largely referred to as canine infectious respiratory disease complex - a respiratory infection that can be caused by a range of viruses, bacteria and Mycoplasma).
As part of the story, they state that if you have a sick dog, the "best course of action is to call your local veterinarian and get medication." I realize it's a quick statement, perhaps tossed in without much consideration, but there are some important issues to consider.
Should someone call a veterinarian and get medication, or should a veterinarian actually see the dog?
- Sometimes dogs just need to be given time and rest. Viruses are often the cause of this condition, and it just takes time for the infection to resolve (just like person with a cold virus). If that's the case, a little over-the-phone veterinary advice might be fine. If drugs are needed, then the dog needs to go to a veterinarian. Affected dogs might need something to control cough, which need to be given by prescription, and occasionally antibiotics are needed, but in either case a veterinarian needs to see the dog first. If the dog is sick enough that it needs additional treatment above and beyond this, then of course it needs to be seen by a veterinarian.
Are there any problems with a dog like this going to the veterinarian?
- Here's where the ball often gets dropped. The last thing we want to see is someone walking through the from door with a hacking, biohazardous dog who goes nose-to-nose with other dogs in the waiting room, breathes on half of the surfaces in the room, sits there for ten minutes while waiting for the appointment, and gets handled by every staff member before they realize the dog might be infectious. A situation like that can turn a veterinary clinic into a source of infection for many other dogs, and help an outbreak spread.
A very basic but well coordinated approach can greatly reduce the risk of dogs infecting other dogs in the clinic. These would include:
- Not taking a biohazardous dog into the waiting room. The owner can call from the car upon arrival or come in without the dog to let the clinic know they're there.
- The dog can be admitted directly into isolation or an exam room, thereby avoiding contact with other animals in the waiting room or elsewhere in the clinic.
- Veterinarians and techs that are going to work with the dog can know in advance and come in prepared, wearing appropriate protective outerwear (e.g. gloves and a labcoat or gown that they use for only that appointment) to prevent contamination of their clothing or body.
Very easy to do. Probably very effective too, but often not done.
I've written about this topic before, but it's an important (and increasingly common) issue to understand, so bear with me while I address the subject again.
I typically get multiple case consults in person, by phone or by email about methicillin-resistant (MR) staphylococci every day. A lot of these start with "I have a case with an MRSA infection..." While trying not to be rude, I tend to interrupt the conversation at that point with "Is this actually Staph aureus or another staph?"
I do this for a few reasons:
- A few years ago, the vast majority of "MRSA" infections in dogs, cats, horses and other companion animals were actually MRSA - that is methicillin-resistant Staphylococcus aureus. However, in the past few years, there's been a tremendous upsurge in other MR-staph, particularly booming numbers of MR-Staphylococcus pseudintermedius (MRSP) infections in dogs. These days, if it's a dog or cat, when I ask the "What staph is it?" question it's usually not actually MRSA. We're starting to see more MRSP in horses too, complicating things in that species as well.
- Staph are divided into two groups, coagulase positive species (which include S. aureus and S. pseudintermedius) and coagulase negative species. The coagulase negative species are commonly found in or on healthy animals and are often methicillin-resistant, but they are not very virulent and don't usually cause disease outside of very high risk populations (e.g. very sick animals in a veterinary hospital). If a MR coag-negative staph is isolated, I am far from convinced it's the culprit, and typically the real cause of the problem still needs to be found.
- MRSA is much more of a concern from a public health standpoint, as it can move between animals and people. While MRSP can cause human infections, these are extremely rare.
- MRSA is not really adapted to live in dogs, cats, horses and many other animals. It can, for a while, but doesn't do so longterm, and the vast majority of MRSA carriers will get rid of it on their own. In contrast, it appears that MRSP (at least in dogs) can stay with the animal for a very long period of time. Therefore, an animal that has had an MRSP infection has a reasonable chance of shedding the bacterium for a long period of time, which might be of relevance for its health in the future.
- The two main MR-staph of concern in companion animals are MRSA and MRSP. Some diagnostic labs still don't try to differentiate the two, despite the fact that there are different guidelines for determining whether they are methicillin-resistant. If someone has a result that doesn't differentiate MRSA from other staph, I tell them their lab isn't doing things right and they need to talk to them so they can have confidence in the results.
More information about MRSA and MRSP can be found on the Worms & Germs Resources page.
The latest edition of the journal Orbit (a journal dealing with eyes, not planets) describes an uncommon infection linked to a pet dog. The article (Zuberbuhler et al 2012) outlines 'acute unilateral dacryocystitis' in a 23-month-old girl (translation: .acute=sudden, unilateral=one side, dacryocystitis=inflammation of the nasolacrimal system, which is made up of a small sac and duct that runs from the eye to the nose).
In this case, the child had been playing in a gated children's area in a city park. At one point, she rubbed her eye after touching the ground, and shortly after the parent noted that the area around her eye had dog feces on it (not sure how they confirmed it was dog feces, but it's a logical guess). Two days later, she was taken to an emergency room because of severe swelling around the eye. A culture from the eye detected Pantoea, a bacterium that can be found in the intestinal tract of many different animal species (including people). It is a rare cause of disease but can cause infections when given the chance (such as being rubbed into an eye, or a wound, or other compromised sites).
While the bug and the infection may be a bit unusual, it's far from surprising to find an infection caused by fecal contamination. It reemphasizes the importance of basic hygiene measures such as hand washing (especially when feces are involved) and supervision of children, along with responsible pet ownership to prevent fecal contamination (i.e. picking up after your dog), particularly in enclosed children's playgrounds.
Norovirus sucks. It's been a while since I had it, but it doesn't conjure up fond memories. A bunch of Canadian tourists returning from Cuba (and presumably all of the other people on their planes) can also attest to the unpleasant nature of this viral infection.
Norovirus in people is (logically) caused by human norovirus. There are some other types of norovirus that infect other species, but the human version predominantly infects people. Predominantly doesn't mean always, though, and other hosts of the virus need to be considered. A recent study published in the Journal of Clinical Virology (Summa et al 2012) looked at whether human norovirus could be found in dogs. Researchers collected fecal samples from 92 indoor pet dogs in Finnish households where people had vomiting and diarrhea or where the dog owner had had close contact with someone with norovirus. Fecal samples were tested for the presence of the virus using molecular tests.
Norovirus was detected in feces of 4 of the 92 (4.3%) canine fecal samples. All positive dogs were from households that had more than two sick people. Additionally, kids were present in all households with positive dogs. Two of the dogs had been sick, with nausea and loss of appetite. Illness in the dogs was pretty mild and only present for one day, and it's not clear whether norovirus was responsible. Fecal samples from owners were only available from one of the positive households, and there the same norovirus strain was found in the owner and the dog.
These results are interesting and indicate that a small percentage of dogs in contact with people with norovirus can shed the virus. The big question is, "what does this mean?" That's not so clear. Finding norovirus in the dogs' feces is one thing. Determining that it's relevant to human (or animal) health is another, and it's important not to over-interpret the results, because...
- The testing that was used detects norovirus RNA, i.e. genetic material from the virus. That means that the virus passed through the intestinal tract. It does not necessarily mean that live virus was present, since this type of testing detects both live and dead virus. Dead virus obviously poses no risk to anyone.
- Even if live virus was being passed in the dogs' feces, the amount of virus coming out the rear end of the dogs isn't known. It might be pretty low and therefore of less concern.
- The relative risk posed by the household dog is a big thing to consider. All dogs that were shedding the virus were from households with multiple sick people, therefore they were already in pretty biohazardous environments with lots of virus being tossed around (in many different ways). This suggests that it may take a lot of exposure for dogs to shed (potentially only a little) virus. Also, it minimizes the relative risk posed by the dog, since if only dogs from severely affected households shed the virus, the dog is only one of many possible sources and probably of lesser risk than exposure to sick people and environmental surfaces they contaminated. Dogs from households with active disease are probably not very likely to encounter lots of other people or dogs (probably less so than the people in the house), therefore limiting their potential role in transmission. There's no evidence that dogs are long-term carriers of norovirus.
Does this change what you should do if you have norovirus? Not really. It means you should try to limit contamination of the environment, wash your hands frequently, stay away from others as much as possible and avoid puking on your pets. Maybe we should add "keep your dog isolated along with you," just in case.
Another interesting finding was the association between sick kids and norovirus-shedding dogs. It's further evidence of the "kids are biohazardous" theory. We know that kids are at increased risk of various infectious diseases. At the same time, we have previously shown that contact with kids is a risk factor for dogs shedding Clostridium difficile and MRSA. Whether that's because kids are more likely to be shedding these bugs, they have closer contact with pets, they pay less attention to hygiene or a combination of these isn't clear, but this result isn't particularly surprising. (No, I'm not recommending banning kids from pet-owning households. As parents, we know our kids are effective disease vectors... that's just part of having kids.)
This study doesn't tell us whether pets are sources of human norovirus, and we really shouldn't expect it to. A single study rarely answers all the questions, and good studies sometimes raise more questions than they answer. This is an interesting study and it shows that more work is indicated to clarify the answers to the questions raised above, and to determine whether there is any real concern about dogs and this nasty virus.
An article in the Winnipeg Free Press by Dr. W. Gifford-Jones, MD, talks about recurrent yeast infections in women. It covers several pertinent points, such as the fact that lots of women who think they have yeast infections actually have different types of infections, and that over the counter treatment might be a concern because of the lack of a proper diagnosis.
Why mention that here? Because of a little anecdote at the end of the story (and one that's gathering the most attention).
'My colleague, faced with repeated failure, decided to ask if his patient had an animal living with her. She replied she did have a small dog and the dog did, in fact, enjoy the comforts of her bed on many occasions. But that was nothing new. It was only after intense probing that she finally admitted with embarrassment to teaching her dog a trick. Since she was away all day at work, she had taught the dog to urinate in the bathtub! The dog had a yeast infection!'
Good for them for thinking about pets. It may have taken time to get there, but at least the question came up. However, this may be yet another example of finally asking the question but stopping the thought process too soon.
Was the pet a possible source of recurrent yeast infection in the person? I can't discount the possibility. We really don't know much about the potential for transmission of this kind of infection, but the pet could have been contaminating the bathtub, leading to subsequent exposure of the person.
Did the pet really have a yeast infection? That's an important question, since they just finished saying a lot of women who think they have a yeast infection don't actually have one. I wonder whether the yeast infection was properly diagnosed by a veterinarian.
Was there any evidence that, if they both had an infection, the same bug was involved? Probably not. However, if you really want to know if the pet is potentially involved, a culture of both the pet and owner to see if the same yeast is present would be needed. Is it really worth doing? Perhaps, because if the pet and person have different yeast, it means that the MD needs to keep looking for possible causes of recurrent infection.
Could the pet have been getting infections from the owner? Possibly. If a pet and person have the same infection, and it's not an infection that classically originates in a pet, then you have to consider the direction of transmission. If the woman had recurrent yeast infections, she could have been regularly contaminating the tub, where the dog could have been exposed when peeing.
It's an interesting case that should raise some questions and hopefully lead to more thought about pets as a potential source of infection in cases like this, but at the same time, a more thorough investigation as well.
Pasteurella multocida is a bacterium that's commonly found in the mouths of dogs and cats. It's a common cause of cat and dog bite infections in people, but can also be spread through close contact with pets (without bites). It's logical to assume that the closer the contact, the greater the risk of transmission. A recent report in Clinical Infectious Diseases (Myers et al 2012) describes three people with life-threatening Pasteurella infections. A unique aspect was all three people got sick from nursing dying pets.
- A 55-year-old woman with sore throat, fever and difficulty swallowing was diagnosed with epiglottitis (inflammation of the epiglottis, a part of the throat region) and hospitalized. Pasteurella multocida was identified on a blood culture. It was subsequently revealed that she had provided palliative care to her dying dog. As part of this, she was dropper-feeding the dog honey, and also eating honey with the dog from the same dropper.
- A 63-year-old woman with sore throat, difficulty swallowing and hoarseness was diagnosed with uvulitis (inflammation of a different part of the throat region) and narrowing of her airway. As with Case 1, P. multocida was isolated from her blood. Her cat had died six weeks earlier and she had "continuously held, caressed, hugged and kissed her cat during its last 7 days of life."
- A 66-year-old woman was hospitalized with fever, chills, cough and difficulty breathing. She had severe pneumonia and P. multocida was grown from a sample of respiratory secretions. Two weeks before she got sick, she had provided palliative care for her dying cat, by "holding, hugging, and kissing the head of the cat and allowing the cat to lick her hands and arms."
Fortunately all three women recovered from their infections, but the severity of disease is certainly a concern. As is common, there was no attempt to see whether the implicated pets actually carried the same Pasteurella multocida strain as the owners, but here the authors at least had a good excuse, since all of the pets had died before the owners got sick.
There are some interesting points in the Discussion section of the paper.
"Our 3 patients’ histories of having recently provided palliative pet care to their dying animals were obtained only after P. multocida was identified in cultures and only after subsequent detail-oriented, animal contact histories were obtained."
- Pet contact (or animal contact in general) is still not asked enough by physicians investigating unknown illnesses. It's unclear whether it would have made a difference in these cases, but knowing more and knowing it earlier can help speed the path to the right diagnosis. Here, pet contact was only considered after a pet-associated bacterium was identified.
"Simply asking whether or not the patient had a pet would not have uncovered the defined association of these respiratory illnesses with palliative pet care. The patient with P. multocida uvulitis even denied having a pet (it had died 6 weeks previously) and only admitted to having provided palliative pet care when asked specifically if she had any animal contacts in the past 3 months."
- This shows some of the challenges and how care must be taken when asking about pet contact. Simply asking "Do you have a pet?" doesn't cover it.
"Only diligence and very detail-oriented, pet-related histories will likely uncover further patients with invasive P. multocida infection related to the pet owner’s provision of palliative pet care to dying animals."
- This shouldn't be focused on palliative pet care, since that's a minor component of pet contact. Many other people have close contact with their pets, even when the pets are healthy. It's something that should be considered at all times.
The Redlands Animal Shelter in California is looking into bird control measures after blaming Giardia infections in dogs on exposure to wild bird poop. On Facebook, Redlands Friends of Shelter Animals have declared "We have a serious problem with birds at the shelter. They land on the kennels and poop goes into the water bowls and give the dogs giardia - which is a parasite that gives them explosive diarrhea."
Giardia is a protozoal parasite that can cause diarrhea in dogs and other species. It can also be carried by healthy dogs, at relatively high rates in some groups. The scope of the problem at the Redlands shelter isn't clear since the news article only talks about one case. Whatever the scope, shelter management is blaming the birds.
Apparently, discussions are underway with different companies about a solution to the bird problem, something that is anticipated to be expensive. However, it's all too common for people to jump the gun on expensive interventions when there's an outbreak and overlook the root causes. While news reports don't always give the whole story, I'd be wary about blaming birds without much more evidence.
Can wild birds carry Giardia? Yes. However, there's more to the Giardia story than that. It doesn't sound like they've actually tested the bird feces to determine whether Giardia is there. Additionally (and critically) it doesn't sound like they've determined the type of Giardia that's infecting the dogs. There are different types (assemblages) of Giardia and most have a limited range of species they can infect. The vast majority of dogs with Giardia in most regions are infected by Assemblage D, a dog-specific strain that comes from other dogs and poses no risk to people. I'm not aware of Assemblage D being found in birds. Dogs can also be infected by Assemblage A, a type that infects people, and also can infect birds.
So, if Assemblage D is involved, they need to look at transmission between dogs within the shelter. If Assemblage A is involved, they still need to focus on dogs but could investigate birds as a potential source.
Overall, Giardia transmission is much more likely due to breakdowns in cleaning, disinfection, hand hygiene and general shelter practices rather than birds pooping in water bowls. It's a lot cheaper to address these shelter management practices (which will also help control various other infectious diseases) rather than dumping a lot of money into controlling bird exposure when in fact that may not be causing the problem. Trying to reduce exposure to bird poop is a good thing as a general practice, but it's important to focus efforts and resources on finding and addressing the true root problems during an outbreak.
More information about Giardia can be found on the Worms & Germs Resources page.
The executive director of the SPCA of Niagara is under pressure from charges that he's "presided over the killing of hundreds of animals." As is common with shelter controversies, sorting through the emotion and rhetoric is difficult. At best, running a shelter can be a thankless task, due to the overwhelming number of animals, emotion, lack of understanding by the public (and often personnel) of the relevant issues, financial challenges and often poorly designed facilities. At the same time, bad things do happen in shelters, and it's critical to put in the time and effort to determine whether things are being done poorly and what needs to be fixed. Here are some of the issues from the Niagara situation.
"From Oct. 1 to Dec. 15, the local SPCA euthanized 473 cats and 100 dogs, a staggering total of killings, according to sources familiar with the situation at the Lockport Road shelter."
- Apart from the problem of relying on information from anonymous sources, it's hard to put this number into context. You need to know the overall number of animals that come in and the shelter's capacity. It's a sad fact that about 50% of cats are euthanized at most shelters internationally because of massive overload. Shelters shouldn't be cat warehouses. It does no one (including the cats) any good to stockpile huge numbers of cats that never have a chance of adoption, and it creates a perfect environment for disease outbreaks. So, while that number of animals seems high at first glance, it may just reflect the reality of supply and demand, shelter capacity and the health/adoptability status of the animals.
"When he was hired, Faso admitted, “My animal care experience is very minimal.”"
- A shelter director doesn't need to be an expert in shelters and animal health. In fact, some excellent shelter directors have come into the job with no experience whatsoever. Their job shouldn't be running animal care. They should be running the shelter, managing personnel, raising funds, liaising with the community and doing a host of other activities. The key is having good veterinary and animal care support, and a willingness to listen to those people. It would be great if every shelter manager was a veterinarian with a shelter medicine residency under his/her belt, along with an MBA and training in communications, but that's not going to happen. Someone with little animal knowledge but the ability to listen and take advice can be an excellent shelter director.
"McAlee and others tell horror stories of animals brought to the shelter for surrender or picked up on the streets and in need of medical care, who are then left to suffer in their cages. In one case, a cat that appeared to be suffering from a broken jaw was brought in and allowed to stay for a week in a cage without treatment. Finally, a concerned staffer took the cat to an emergency veterinary clinic where it was treated and then returned to the shelter."
- That's a big problem. If true, and if this was done because of pressure from the director overriding advice from medical staff, then that's completely inappropriate. Interference with medical decisions and medical care does occur in some shelters and is a major problem.
"When the cat then developed a common respiratory infection, rather than provide further medication for the animal, Faso directed that it be euthanized."
- This is a tougher issue. I hate to see potentially treatable animals euthanized, but euthanasia is an appropriate response in some situations. If they are unable to properly manage an infectious case or are overwhelmed with healthy cats, keeping an infectious cat may pose a huge risk to all of the other cats in the facility. It's impossible to say much here without more details.
"Other sources tell the Gazette that cats at the shelter have been injuring themselves in out-dated display cases and that a donor offered to fund the replacement of those cages. Faso, reportedly, refused to accept the donation."
- Poor housing is a common problem in shelters. Good cages are expensive. It would be bizarre for a shelter manager to turn down money (that came with no strings attached) and if that was done, it would be another sign that Mr. Faso's not right for the job.
"..he has reportedly told board members and others that the local SPCA will “never be a no-kill shelter because it’s too expensive."
- That's an unfortunate fact. No kill shelters just aren't viable in the grand scheme of things. Individual shelters can be no kill, but that's often done by cherry picking the adoptable animals.
It comes down to math. If 50% of cats coming into shelters are euthanized every year because of lack of space, to convert to a no-kill approach we'd need to massively increase shelter capacity every year to accommodate the increasing population. Millions of dollars would be required to create cat warehouses where millions of unadoptable cats lived marginal lives in facility confinement until dying of natural causes or from the massive disease outbreaks that would be certain to happen. I know I'll get reams of emails complaining about this paragraph, but to me it's a simple fact. If you increase supply by 100% per year by not euthanizing any animals, and demand doesn't increase, the math quickly shows you the size of the problem that would be created.
The only way to get to the point where no-kill is a viable approach is to have more responsible pet owners and better animal population control. Euthanasia rates are much, much lower in dogs, in part because of much better population control and also because people tend to try harder to recover lost dogs compared to lost cats. Recovery rates of lost dogs that make it to shelters are very high. Cats... not so much.
So, if you want to help out shelters and the animals in them:
- Spay and neuter your pets.
- Donate to good quality shelters to help them provide optimal care.
- Volunteer, if you have the time and interest.
- Hold shelters to a high standard, but make sure it's a realistic standard.
- Encourage municipalities to properly fund animal shelters and enforcement.
- Consider adopting from a shelter if you are getting a new pet.
- Take the time to learn about the issues, and make assessments based on fact, not just emotion.
A paper in the journal Orthopedics (Machino et al 2011) describes the case of a 52-year-old man with an infection in the vertebrae of his neck caused by Pasteurella haemolytica. This bacterium (which was renamed Mannheimia haemolytica quite a while ago... I guess their laboratory is a bit behind the times) is most often associated with respiratory disease in cattle. In this case, "because the patient owned 2 dogs and frequently kissed them on the mouth, the cause of infection was thought to be excessive contract with pet dogs."
It's possible, but I have some issues with this.
- Despite the assertion in the paper that this bacterium is a resident in the mouth of dogs and cats, I don't know of much or any evidence supporting this. A different but related bacterium, Pasteurella multocida, is commonly found in the mouths of healthy dogs and cats, but it's not the one that caused disease here. The authors state that Pasteurella haemolytica can be found in 71-90% of cats and 21-60% of dogs, yet the papers they cite didn't actually find P. haemolytica, they found other Pasteurella.
- The authors also state that the recent increase in pet ownership has caused an increase in P. haeamolytica infections from bite wounds, with absolutely no evidence supporting either an increase in infections caused by this bacterium or any role of pets.
- This paper takes the typical medical journal approach of blaming the pet with no effort whatsoever to find out if the pet was really involved. Would it have killed them to get some oral samples from the dogs for culture, to see if they could actually find the same bacterium?
It's disappointing, but not surprising, to see reports like this. It shows a lack of critical thought about the potential role of pets, a lack of care when writing the report, and a weak peer review process for the journal.
Zoonotic diseases are an important issue. However, we need to focus our efforts on real problems, not bad science. This article is so weak and error-filled that it should be retracted, but it's unlikely anything will happen. I'll write a Letter to the Editor, which, based on my limited previous experience in questioning poor zoonotic disease science in human medical journals, will likely be ignored. Well, we'll see.
The Toronto Star has an article describing the efforts of Naz Sayani to bring home a group of street dogs from India. As an animal lover, she was touched by the number of stray dogs roaming around New Delhi while accompanying her daughter to India for medical treatment. She borrowed a car and started driving around the city dropping off food for strays.
- This is a high-risk activity for rabies exposure. Rabies is very common in India and contact with strays is a prime source of human infection. Ideally, anyone working with strays should be vaccinated against rabies. At a minimum, they should be aware of the risk and be ready to get post-exposure treatment if exposed (possibly through a quick trip out of the country, since knowledge about rabies prevention and access to rabies post-exposure treatment is variable in India).
A pregnant stray dog caught Naz's eye, and after hearing about people threatening or abusing the dog (and later her and her pups), she tried unsuccessfully to find them homes. Eventually, she made the decision to bring them to Canada, in order to try to find homes for them here.
I can certainly see how this would happen, as it's easy for people to get attached to a friendly, needy animal. It's also hard to balance a case-based scenario like this, when someone has an attachment to a specific animal, with the bigger picture of animal rescues, and all the associated pros and cons.
I get a surprising number of advice calls and emails from people "rescuing" dogs from various places.
- The typical questions goes something like "I am organizing a rescue of a group of dogs from [insert one of many central or southern US states here] and want to know if there are any infectious disease issues I have to worry about".
- Worse are the calls that go "I just got some rescue dogs from [wherever] and now my other dogs are sick. What might be going on?"
People that are rescuing dogs usually do it because they have big hearts. Some people like the "status" that they see attached to certain rescue dogs ("You have a new Mercedes? Well I have a new Hurricane Katrina rescue dog"). My problem with international rescue efforts is the question of a) whether it's a good use of resources and b) whether it poses unnecessary infectious disease risks to people and other animals.
- Organizing rescues, fulfilling regulatory rules, shipping dogs and finding them homes takes a lot of money. It would make more sense if there was a shortage of adoptable strays in Ontario. However, I haven't heard any shelter personnel lament their lack of dogs, undercrowded facilities or excessive financial resources.
- Moving animals between different regions carries an inherent risk of transmission of infectious diseases. The more movement, the more mixing and the greater the difference in infectious diseases in the areas, the greater the risk of making more animals sick, and potentially doing more harm than good.
- Rabies is one concern, and rabid dogs have been imported into North America in the past. Since rabies has a long incubation period, it's hard to be certain that a dog's not incubating a rabies infection.
- More likely to be imported would be a wide range of other bacteria, viruses, parasites and fungi. These are a concern from several standpoints. Some might cause disease in the imported animal, and diagnosis may be delayed or missed because of it being a disease with which local veterinarians have no experience. Some might bring an unusual pathogen into the area that could be spread to a few other in-contact dogs. Worse, some might bring in a new pathogen that could then establish itself in the local (or national) dog population. We don't know how often any of these scenarios occur, but they are always a risk, and need to be part of the cost-benefit analysis of animal rescue operations and associated animal importation.
At the end of the day, it's hard for me to support rescuing dogs from other regions when we already have a large population of dogs in our own shelters and animal being euthanized here because there are no homes for them. I can't justify the expense and risk of importing dogs if, for every new dog imported, one other dog in a local shelter gets euthanized because it doesn't have a home. Does importation really mean fewer adoptions here? We don't know, but it stands to reason.
A situation like this is a little different, as a chance and presumably (hopefully) one-time event prompted by a specific human-animal bond. Overall though, we could do better for the dog populations both here and in regions where there are massive stray problems by focusing attention on better care and adoption here, and international programs aimed at helping stray populations abroad through vaccination, education and sterilization efforts.
Staphylococcus schleiferi doesn't get much respect. Most of the attention gets paid to Staphylococcus aureus (because MRSA, the methicillin-resistant version, is such a high profile pathogen in humans and it can be transmitted between people and pets) and S. pseudintermedius (because it's a leading cause of infection and MRSP, the methicillin-resistant type, is spreading very quickly and widely in dogs).
Staphylococcus schleiferi is another Staphylococcus species that can cause various infections in dogs, particularly skin and ear infections. It's often overlooked, or more specifically, unnoticed. The problem is it takes some effort to differentiate it from other staph. This species is relatively unique in that it has two distinct subtypes - S. schleiferi coagulans and S. schleiferi schleiferi. The first one is very similar to S. pseudintermedius, and not all diagnostic labs go through the trouble of trying to distinguish one from the other. So there may actually be a lot of S. schleiferi infections that get mistakenly diagnosed as S. pseudintermedius. The second subtype is coagulase-negative (whereas S. pseudintermidius, S. aureus the first subtype of S. schleiferi are all coagulase-positive) and most diagnostic labs don't do any identification of coagulase negative staph. As a result, we only have a superficial understanding of it and its epidemiology.
A recent study from the University of Pennsylvania (Cain et al., J Am Vet Med Assoc 2011) that looked at 225 dogs with S. schleiferi infections has provided some insight into this perhaps not-so-unusual bug. Some highlights:
Ear infections and skin infections accounted for 87% of cases.
- That's expected, since these are very common types of infections for any kind of staph.
Allergic skin disease was the most common underlying disease.
- That's also not surprising. Most staph infections occur secondary to some underlying problem or procedure (e.g. surgery). This shows the importance of taking the time and effort to diagnoses and control allergic skin disease, in order to help prevent infections before they occur.
57% of S. schleiferi isolates were methicillin-resistant.
- Ugh! I'm not very surprised but it's scary how often we see methicillin-resistance in some staphylococci, because of the complications it can cause with treatment. Methicillin-resistant staph infections can be hard to treat because there may be few effective antimicrobials available.
Methicillin-resistance was more common in the coagulase negative subspecies, S. schleiferi schleiferi.
- It's hard to say whether this means a lot from a clinical standpoint. In generally, coagulase negative staph are much less of a concern than the coagulase positive staph since they are less likely to cause disease. However, we don't really understand the differences between the two S. schleiferi's. If the coagulase-negative version is less able to cause disease, then a lower rate of methicillin resistance in the more concerning coagulase positive type is better than vice versa, but I'm not sure we have enough evidence to say much about this at the moment.
Treatment with a penicillin (e.g. amoxicillin), first generation cephalosporin (e.g. cephalexin) or 3rd generation cephalosporin within the preceding 30 days was associated with having methicillin-resistant S. schleiferi.
- That's not surprising and is one more piece of evidence that "routine" use of antibiotics can contribute to selection for methicillin-resistant staph. It shows how we need to focus on prudent use of antibiotics.
A question I sometimes get is whether an animal with methicillin-resistant S. schleiferi poses a risk to people. We don't really know, but the risk is probably quite limited.
- S. schleiferi coagulans infections in people are extremely rare, so this bug doesn't seem to have much of an affinity for humans.
- S. schleiferi schleiferi infections in people are more common, but it is thought that this subtype is a "human Staphylococcus." Therefore, while it can cause infections in people (usually infections in people that are already sick and/or in hospital), it probably comes from people, not animals.
- So, overall, the risk posed by infected animals is minimal. However, some S. schleiferi can be very drug resistant and you don't really want to have an infection with a multidrug resistant bacterium of any kind ("you're case is very unique" isn't something you want to hear from your doctor), so using good general infection control and hygiene practices around infected dogs makes sense.
A parvovirus outbreak has been identified at the Occupy San Francisco camp, with at least three dogs affected by the highly contagious and potentially very serious viral disease. The San Francisco SPCA has visited the camp and their temporary clinic was attended by "dozens" of dog owners (indicating lots of dogs at the camp). This is a nice proactive step to help contain the parvo outbreak and hopefully reduce the risk of transmission of various other infectious diseases amongst the animals. Some people appreciated the help. Others (probably the subset that complains about everything) accused the SPCA of spreading bad publicity to help shut down the camp. (I guess they'd rather have good press than healthy dogs.)
In many ways, it's not too surprising. "Occupy" camps are just asking for infectious disease outbreaks, more so in people, but the same risk factors are there for dogs. Whenever you mix together lots of different individuals from different sources, put them in close and prolonged contact and have hygiene challenges, you set the scene for infectious diseases. From a canine parvovirus aspect, heavy fecal contamination from dogs defecating in a small, concentrated area and unvaccinated dogs feed the fire even more. (I don't know for sure that the affected dogs were un- or incompletely-vaccinated, however given the excellent effectiveness of parvovirus vaccines, it's highly likely that sick dogs were not adequately vaccinated.)
Parvo isn't the only infectious disease problem at the camp. Kennel cough (now known as canine infectious respiratory disease complex, CIRDC) has also been identified. This syndrome, caused by a mix of bacteria, viruses and Mycoplasma, has greater potential to spread widely because some of these bugs are highly contagious and vaccination coverage in the population will be lower than for parvo. A large-scale kennel cough outbreak is quite likely if there is kennel cough activity at the camp.
What can you do to reduce the risk, whether it's while "occupying" or during your daily activities?
- Have your puppy vaccinated as per your veterinarian's recommendations.
- Don't take unvaccinated puppies to areas where there will be lots of other dogs. "Unvaccinated" includes puppies who have not had their full initial series of vaccines.
- If your dog is sick, don't take it out in the public, especially to places where other dogs will be present.
- If your dog gets sick during a public event, take it away promptly to reduce the risk of it infecting other dogs.
- Don't let healthy skepticism grow to paranoia, and don't let political squabbles interfere with proper healthcare... both human and veterinary.
Canine influenza continues its rather puzzling spread through the US. After emerging years ago, it has spread sporadically, causing some large regional outbreaks but sparing many areas, and it has moved about in a pattern that's pretty unusual for a highly contagious virus.
There have been various reports of canine influenza activity in the New York and New Jersey areas over the past few months, and an outbreak has now been reported in a PetSmart doggie daycare in Farmingdale (NY) . Eight dogs have been diagnosed with canine flu (though not sure how or whether it's a lab-confirmed diagnosis) and the PetSmart doggie daycare has been closed since November 14. It was supposed to have re-opened on the 22nd, but dogs that had been there won't be allowed back until two week after their last visit, due to the potential that they were infected at the facility and are still infectious.
Like human influenza in people, canine flu is a viral infection that's readily transmissible between dogs. It typically causes mild disease, with coughing as the main sign, but can cause serious (and sometime fatal) pneumonia in some cases. A vaccine is available but it's not considered a "core" vaccine and is largely reserved for dogs in areas where the virus is active and/or in dogs whose lifestyle makes them more susceptible to exposure (e.g. contact with doggie daycare or boarding facilities, contact with many other dogs, travel to areas where the virus may be active).
Interestingly, PetSmart is paying for treatment of the infected dogs. That's pretty surprising, and may set a precedent they might want to avoid. Infectious diseases are a fact of life. We can do things to reduce the risk of exposure, but we can never completely eliminate the risk that our pets (or ourselves) will get an infection. Usually, infectious diseases that happen in facilities are considered an unfortunate fact of life (especially when it's a vaccine-preventable disease) and facilities rarely cover any costs associated with such outbreaks. In reality, this would be a reasonable approach assuming the facility used standard and reasonable practices to reduce the risk of disease.
If a facility has an infection control plan and adheres to it, whether it's a boarding facility or a veterinary hospital, it's hard to expect them to cover the costs of infections, since not all infections are preventable. In contrast, if there is no infection control program or if things aren't done right, it's easier to assign blame and expect some financial support. Sometimes, costs are covered purely on a public relations basis, which is perfectly reasonable as well. There's no indication why costs are being covered here, but it raises some interesting, broader questions about infection control in facilities like this and their role in covering any costs that are incurred from any type of infectious disease exposure.
CTV has a consumer reports segment and a recent topic involved feeding pets "natural" diets (although no one ever defined what that really means). In the report on the CTV Consumer Alert website (it's currently about the third story into the video if you just press play, or you can shortcut to it using the link below the main video window), a 26 year old cat is held up as a poster child for the health benefits of raw food. Making it to 26 is a noteworthy accomplishment for a cat, but it's far from rare, and you can't know whether the cat survived because of its diet or despite its diet. At the end of the clip, they mention he cat has kidney disease, not an uncommon problem in older cats but one that is often blamed by raw proponents on commercial foods. It's also not a condition that I'd want to see someone try to manage with a raw diet.
Anyway, the story has the typical statements (including one from a veterinarian) about how raw and "natural" diets produce a healthier animal, stronger immune system and shinier haircoat, but without citing any proof (because there is none) and with no discussion whatsoever about the potential animal and public health impacts of raw meat feeding.
Good investigations are good. Quick reports put together with little thought or consideration of the issues are just time filler. The host, Pat Foran, said in his conclusion that "natural" pet foods have less filler so there's less to come out the back end of the dog. Well, news reports comprised of filler produce the same kind of by-product.
If you are going to feed raw, at least take the time to research how to do it safely, both for your pet and your household. Raw feeding can be done in a nutritionally sound manner, but it takes time, effort and money. Some people are willing and able to do that, but if you're not, don't feed raw. Raw feeding also carries some risk of gastrointestinal disease like salmonellosis in the animal as well as exposure of people in the household to those same bugs. Certain households, particularly those with high risk individuals (e.g. elderly, infants, pregnant women, immunocompromised persons) should avoid raw feeding or only use products that have been high pressure pasteurized. There are a few commercial raw diets that are treated in this manner and these are preferable as the process should kill most relevant bacteria, reducing or eliminating the infectious disease risks to pets and people.
Like many other things in life, the key is being informed so you understand the risks and benefits, and whether recommendations made by people have any substance behind them. Too often, people make a major change like feeding raw based on a comment on a website or from another dog owner, with no clue about the issues and no effort to figure out how to do it right. That's just asking for problems.
More information about raw diets can be found on the Worms & Germs Resources page.
Canine influenza continues to be a problem in some areas of Texas, most notably in the Austin area. A recent news report indicates 30 confirmed cases and 70 suspected H3N8 canine influenza cases since September.
It's hard to say what the scope of the problem really is, but something's definitely happening. Getting good data about infectious diseases of companion animals is difficult because there is no central surveillance program and government animal health agencies tend to have little interest in non-food animals. Data tend to be assembled by word of mouth, which can lead to either over- or under-estimation of the problem. As highlighted by the number of "suspected" cases, lack of diagnostic testing is also an issue. Since dog owners have to pay for the testing themselves and since, for influenza, test results rarely change what's done for initial treatment of the dog, many people are reluctant to have the tests done. That leaves us with large numbers of unconfirmed cases, as is this situation. When there is documented flu activity in the area, a suspected case could quite likely be influenza. The bigger problem is in areas where flu is not common or hasn't been found, because canine flu looks no different than several other causes of respiratory disease, and knowing whether it's really flu is important for making vaccination decisions, as well as implementing certain infection control measures.
Avoiding exposure to canine flu is tough in areas where flu is active, just like it is for people when human flu is circulating. One of the big problems is that infected dogs start shedding the influenza virus from their respiratory tract before they get sick. Therefore, staying away from sick dogs and keeping your dog at home if it has signs of disease can't completely prevent exposure. However, these steps are still very important as they can help reduce the risk. Vaccination is another measure to reduce the risk. Vaccination is not 100% protective but it is an important part of influenza control in dogs that might be exposed to the virus.
Veterinarians at Michigan State University's College of Veterinary Medicine are warning of an upswing in leptospirosis in dogs in the Detroit area. More than 20 cases of leptospirosis have been reported in dogs in the Detroit area, and it's likely that many more unreported cases have occurred. Leptospirosis, a bacterial infection, can cause very serious disease, including potentially fatal renal failure. It can be vague and hard to diagnosis if people aren't thinking about the disease. The most commonly identified problem is kidney disease, and early diagnosis and treatment is critical for successful treatment.
The Leptospira bacterium can survive well in the environment, particularly in moist conditions, and dogs are often exposed through wet environmental areas that have been contaminated with leptospires from the urine of infected wildlife. The strain that has predominated in the latest Michigan cases is Leptospira Icterohemorrhagiae, a type most often associated with rats.
Prevention of leptospirosis involves avoiding exposure to the bacterium as much as possible (largely through avoiding contact with wet areas where lepto cases have been identified) and vaccination. Vaccines are available for dogs and they can reduce the incidence and severity of disease caused by four different lepto types, including Icterohemorrhagiae. Vaccination should be considered in dogs in regions where lepto cases are identified and in dogs at increased risk of exposure based on lifestyle and travel.
There have been a few large outbreaks of dead birds around Ontario lately, with botulism being the main suspect. In one area alone, up to 6000 dead birds have washed up on Georgian Bay beaches. While dramatic, it's not a rare situation at this time of year, and typically relates to birds ingesting fish that died of botulism. When birds eat enough fish with enough botulinum toxin inside them, they can develop botulism themselves and die. This pattern can continue if dead birds are eaten by other animals.
In response to these events, I often get calls about risks to dogs and people. When thinking about it, it's important to consider how botulism occurs. There are two main forms of botulism:
- Toxicoinfectious botulism involves growth of the Clostridium botulinum bacterium in the intestinal tract, and as the bacterium multiplies it produces toxin which can be absorbed into the body through the intestinal wall. This type of botulism is rare in adults (both people and animals), since the mature intestinal bacterial population usually prevents C. botulinum from overgrowing. It's mainly a risk in young individuals. )This is why you're not supposed to give honey to babies, since C. botulinum spores that can be present in honey can pose a risk to them.)
- The other form of botulism in from ingestion of botulinum toxin that's already been produced. This is the most common form. When birds eat fish that have died of botulism, they ingest both the bacterium and its toxins, but it's the toxins that make them ill and ultimately lead to death. Dead birds will probably have some C. botulinum in their intestinal tracts, but the main concern is the botulinum toxin in the rest of their tissues.
Dogs (and cats) are quite resistant to botulinum toxin, and reports of botulism in these species are rare. It would take a pretty large amount of toxin to cause disease (at least compared to many other species) but it's not impossible. Casual contact with areas where birds have died is of basically no risk. Eating dead birds could pose some risk to the dog, depending on the amount eaten and how much toxin was present in the bodies. Ingestion of some C. botulinum bacteria in the birds is of limited concern.
So, walking in an area where birds have died is very low risk. People should ensure that their dogs don't have uncontrolled access to areas where birds have died, so that they can't eat lots of dead birds.
I also get questions about whether dogs that get exposed to beaches where birds have died pose any risk:
- Even if a dog ate a lot of dead birds and got botulism, a person could only be exposed to that toxin by eating the dog - an unlikely event. The dog could ingest some C. botulinum bacterium, but this also poses minimal risk since the bacterium is pretty widespread and people can be exposed to it from many different sources. Even if a dog had some C. botulinum in its intestinal tract, avoiding contact with feces will reduce the risk of exposure. Even if there was some ingestion of C. botulinum from the feces, there's little risk, especially to adults. Perhaps the main public health concern (which is still very low) would be exposure of infants to C. botulinum from dog feces or perhaps from a dog's contaminated haircoat.
Bottom line: Keeping dogs and cats away from dead birds is a good idea, for several reasons, including botulism exposure, but there's limited public health concern.
Image: Dead birds washed up on the shore of Georgian Bay, on the eastern side of Lake Huron (click for source)
We seem to be seeing more canine papillomavirus cases in dogs in the area as of late. It isn't a high profile disease - the virus doesn't typically make dogs sick, it usually just causes warts. Whether there is actually an increase in cases or we're simply looking for them more carefully is unclear, but it may genuinely be on the rise.
Canine papillomavirus can cause a range of skin problems in dogs, typically warty lesions (papillomas) that go away over time without specific treatment. Usually, a small to moderate number of warts are found in the mouths of infected dogs (see picture right). Sometimes, the lesions can be large and extensive, causing problems and requiring surgical removal. Most often (like warts in people), it's merely a cosmetic issue that goes away eventually, but it may take months. Depending on the size and extent of the lesions, and whether they are growing or causing problems, treatment may be recommended. This can include crushing a wart to try to stimulate the body's immune response, or topical administration of certain drugs. Complete removal of the lesions surgically should be curative.
Canine papillomavirus is spread by direct contact between an infected dog and a susceptible dog. However, because it tends not to cause severe disease, this virus doesn't get a lot of attention in the research world. However, a recent study (Lange et al J Clin Microbiol 2011) has provided more insight into the virus. In the study, researchers evaluated different ways to identify the virus. They then tested 95 healthy dogs at the University of Zurich and identified viral DNA on the skin or in the mouth of over 50% of the dogs. Whether these healthy dogs pose a risk to others is currently unclear, but it suggests that the virus could be transmitted not only from dogs with skin lesions, but from a large number of normal, healthy dogs. If that's the case, control will be a lot harder, since focusing on just the "sick" dogs (the ones with skin lesions) would miss a big pool of potentially infectious animals.
It's important to note that people cannot be infected with canine papillomavirus, nor can dogs be infected by papillomaviruses from other species.
Image from: www.marvistavet.com
A recent article in the Toronto Sun described one physician's approach to dealing with dig bites in kids. It contains some useful information, but also a couple of areas that probably require some clarification.
In the article, the physician lays out a few points regarding management of dog bites in kids:
The first thing a parent should do after such a bite is to stop the bleeding by applying pressure. Then, clean the area with warm water and soap. Dogs, like humans, have dirty mouths, so you want to wash and rinse well and even flush out the wound if it's deep.
- "The solution to pollution is dilution" is a old adage. Thorough cleaning is a critical step.
If the bite wound is small, it's usually not sutured, as this might increase the risk of infection. On the other hand, facial wounds and larger bites have to be well cleansed and irrigated, and may require stitches. The sooner this can be done the better.
For a child with a dog bite that has broken the skin, most pediatricians would recommend a seven-day course of an antibiotic, typically Augmentin (unless the child is allergic to penicillin).
- I'm not sure "most" doctors would start a child on antibiotics after any bite that has broken the skin - at least I hope not. Typical recommendations for bites include that antibiotics should be considered with moderate to severe injuries, puncture wounds, people with compromised immune systems and bites over specific areas like joints or the face. Antibiotics for minor soft tissue injuries in otherwise healthy individuals are not typically recommended, although there is some controversy.
Rabies is usually not a risk in dogs that are family pets and live in homes. If the dog is not known or their rabies status is unclear and you can't locate the pet, check with your pediatrician about rabies prophylaxis.
- True. Rabies from pet dogs is very rare in North America. However, if you get it, you almost certainly die, so we take precautions even in low risk situations. So, a little more discussion of this point is important.
- Every dog bite must be approached as a potential rabies exposure. Key points for this are identifying the dog and ensuring it's quarantined for 10 days. After 10 days, if it's healthy, it couldn't have transmitted rabies with the bite. Related to this, any dog bite should be reported to local Public Health personnel. They will ensure that quarantine is imposed if the dog is known, and facilitate rabies post-exposure prophylaxis in the rare situations that it is needed. In Ontario, physicians are bound by law to report bites to Public Health.
Dog bites are unfortunately very common. Usually they are minor and heal without much trouble, but serious or fatal injuries can occur and infections are a potential problem. Knowing what to do in response to a dog bite is important to reduce the risk of a range of complications.
The CDC's annual animal rabies surveillance report has been published in a recent edition of the Journal of the American Veterinary Medical Association (Blanton et al 2011). It's the regular synopsis of the state of rabies in domestic animals and wildlife in the country. It contains some interesting information but few surprises. Among the highlights:
- Rabies was identified in 6154 animals in 48 US states, plus Puerto Rico. The true number of animals that died of rabies in the year would have been much higher, since not all animals (particularly wildlife) that die of rabies get tested.
- 92% of positive animals were wildlife, including raccoons (37% of cases), skunks (24%), bats (23%) and foxes (7%).
- Cats were the most commonly affected domestic animal, accounting for 4.9% of cases (303 cats), followed by cattle (1.1%), dogs (1.1%) and horses (0.6%).
- Different rabies virus variants predominated in different regions. For example, raccoon rabies virus was most common on the east coast. Different skunk rabies variants predominated in the south-central and north-central regions, along with California and Nevada. A couple of pockets of fox rabies were present in the southwest, along with one in Alaska. Mongoose variant was present in Puerto Rico. Bat variants were spread out across the country.
- Most rabid cats were from states where raccoon rabies is endemic. About 1/3 of infected cats were from Pennsylvania and New York. Texas was the leader in dog rabies, followed by Puerto Rico and Virginia.
- Two cases of rabies in humans were identified, compared to 4 in 2009. One was a migrant worker infected by a vampire bite while in Mexico. The other was a man from Wisconsin who was infected with a bat rabies strain. Both died.
Canadian and Mexican data are also reported:
- 123 cases of rabies were identified in Canada, 93% of which were wildlife. 7 (5.7%) were dogs or cats. No rabid raccoons were identified, continuing a trend that has been observed since 2009. Bats and skunks were the wildlife leaders. No people were infected.
- 357 cases were reported in Mexico. 83% were cattle, 20 were dogs. Four human cases were identified.
While rabies does not exert anywhere near the impact on people in North America compared to many other regions (where tens of thousands of people die from the disease every year), it continues to take its toll on wildlife and, to a lesser degree, domestic animals. It's also a preventable disease that can be controlled with vaccination, and human cases can effectively be eliminate by proper post-exposure treatment. Continued efforts are needed to reduce rabies in wild and domestic animal populations, for both the protection of those populations and protection of the people who may come in contact with them.
While it's not really an occasion to celebrate, September 28 was World Rabies Day. Rabies has been a problem for millennia, and it's not going away any time soon. This viral disease, which is almost invariably fatal, kills 50 000 - 70 000 people per year. Some countries have astounding rates of rabies cases, such as India where ~20 000 people die of the disease every year. Internationally, most human rabies infections are caused by dogs, but wildlife are the main source in some regions (such as Canada and the US) . Basically all rabies infections are preventable with proper access to good medical care and rabies post-exposure prophylaxis, but sadly the thousands of people who die do not receive treatment.
Is rabies controllable? Yes. With measures to reduce rabies in wild and stray animals, pet vaccination, public education measures, good access to medical care, adequate rabies vaccine supplies and adequately trained healthcare personnel, the incidence of rabies can be dramatically decreased. However, these measures require time, money, effort and political will, and those are limitations in some areas.
Can rabies be eradicated? That's a tough question. Eradicating a disease that can be found in many wild animal species internationally is extremely difficult. It's hard to envision complete eradication of this virus, as was done for smallpox (a human-only disease) and rinderpest (a cattle-only disease). Both those diseases had the advantage of only being found in one species, making control and eradication much more feasible. However, while we might not be able to eradicate rabies, it's certain that tens of thousands of lives could be saved every year with good rabies control programs.
More information about rabies can be found in on the Worms & Germs Resource page.
An outbreak of canine influenza is occurring in San Antonio, TX, as this virus continues its strange and unpredictable movement through the North American dog population. In an article published on a local San Antonio news website, Dr. Michele Wright, a San Antonio veterinarian, reports 20 confirmed and 70 suspected cases over the past month. It's not clear whether these are all from her clinic, nor is there any information about possible sources of the virus or the severity of disease. Dr. Wright also states that the virus has been identified in Austin and Dallas.
It's not particularly surprising that canine flu has been found in Texas. It's now been identified in at least 38 US states, as well as one Canadian province. An outbreak is not particularly surprising either in this case, because when a virus reaches a new area, it can easily cause widespread disease since it encounters a population of animals that don't have any pre-existing immunity (i.e. antibodies) against it.
What's strange about canine flu is how it has spread across North America. When it was first identified in Florida greyhounds in 2004, it seemed like it was going to spread widely across the dog population. It spread quickly at greyhound tracks and in clusters in Florida and in other states, but it's subsequent spread across the continent was quite patchy - it caused only localized outbreaks in different states, instead of the catastrophic continent-wide epidemic that was anticipated. Whether this relates to the amount and type of direct contact between dogs (e.g. dogs are only infectious for a short period of time and an infected dog has to meet a susceptible dog during that time to continue transmission of the virus, otherwise it dies out), specific aspects of the virus in dogs (e.g. how long it is shed) or lack of recognition of disease in some areas (e.g. mild disease that doesn't get diagnosed) is unclear.
We've been looking for canine flu in Ontario for a few years now, with no "success" (that is, we haven't found it yet).
Are we flu-free at the moment? Probably not. I suspect it's lurking out there, but it's possible that it really hasn't made it to Ontario - yet.
If it's not here now, will it make it here eventually? Almost certainly. It's taking longer than I expected but all it takes is one infected dog entering the country. With the amount of cross-border dog movement, it's probably inevitable.
What about vaccination for canine flu? It comes down to risk of exposure and risk aversion. If flu is in the area, vaccination is a good idea. If flu is in adjacent areas, it's also a good idea. If flu isn't recognized in the area, it's a matter of how much risk people are willing to take and thinking about higher risk situations, as described below.
What about vaccination in Ontario, or other places where the virus doesn't seem to be present? It's hard to say when to recommend canine flu vaccination. Certainly, vaccination of dogs traveling to areas where canine flu is or has been present is a good idea. Vaccination of dogs that engage in high risk activities such as going to shows or kennels is also prudent, since these are the places where we may see the firsts outbreaks if/when canine flu makes it here. Vaccination of low-risk dogs in the province is probably not necessary at the moment (unless people are very risk averse and don't want to take any chances).
Why vaccinate? It's just "the flu"... This is an attitude that the human public health field battles all the time. Most people who get human influenza (humans can't get the dog version of the virus) feel crappy for a few days and get over it. The perception that it's only and always a mild disease keeps some people from getting vaccinated. However, thousands of people die from flu complications, particularly the very young and elderly individuals. Vaccinating everyone helps reduce the chance that these high-risk people will get sick. Also, while rare, serious (including fatal) infections can occur in otherwise healthy people. In dogs, there's probably actually more indication to vaccinate if there is a realistic risk of exposure. Canine flu can cause classical flu-like disease, akin to the typical human case. However, severe (often fatal) pneumonia can also occur in otherwise healthy dogs. High rates of severe disease were reported initially when canine flu was first identified. It seems like severe disease rates have dropped, but it's still a concern. I wouldn't be surprised if severe disease is more common in dogs with canine flu than in people with human flu.
Whether or not to vaccinate is a discussion dog owners should have with their veterinarian, considering the risk of exposure, risk of severe illness and risk aversion. At the same time, people in areas where flu has not been identified need to be on the lookout for it, to ensure that it gets diagnosed promptly if it emerges, and that information gets communicated to veterinarians and the dog-owning public so that appropriate responses can be made.
The USDA's Animal and Plant Health Inspection Service (APHIS) has announced proposed changes to dog importation rules. The changes would tighten rules for dogs being brought into the country for resale, research or veterinary treatment. The reason for the sudden changes isn't clear, but it may be the result of a couple of high-profile importations of rabid dogs. Regardless, it makes sense to pay more attention to companion animal importations, as long as the requirements are practical. The practicality aspect is of particular concern for the large number of people that travel between Canada and the US with their dogs, which is pretty low-risk from an infectious disease standpoint. Balancing policies that help prevent introduction of serious diseases with rules that don't unnecessarily complicate the frequent cross-border movement of people and their pets can be tough. This proposal doesn't cover pet dogs, which is both good and bad.
With the proposed changes, dogs imported for resale, research or veterinary treatment must have:
- an original health certificate
- a valid rabies vaccination certificate
- have an APHIS-issued import permit
The health certificate must clearly describe the dog and certify that:
- it's at least six months of age
- it was vaccinated no more than 12 months prior to the date of importation against distemper, hepatitis, leptospirosis, parvovirus and parainfluenza virus
- it's in good health and "free of any infectious disease or physical abnormality that would endanger the dog or other animals or endanger public health, including parasitic infection, emaciation, lesions of the skin, nervous system disturbances, jaundice or diarrhea."
That's pretty standard, however the last statement can sometimes cause issues. Here, the language is better than in some other protocols because it says "disease," not "infection." It may seem like a minor point, but to me it means a lot. If someone asks me to certify that my dog does not have an infectious disease, I can do that. She doesn't have any clinical evidence of an infection. If someone asks me to declare that she's free of infection, it gets trickier, because infection could be interpreted as disease, but it could also be interpreted as simply carrying an infectious agent. Every dog is carrying multiple microorganisms that could "endanger the dog or other animals or endanger public health" but the risk is rather low from clinically healthy dogs. No veterinarian can ever certify that a dog is not carrying any microorganism that could cause disease.
The restriction of importation for veterinary treatment is a bit of a concern, because in some areas the closest veterinary clinics or referral centres are across the border (one way or the other). It's a difficult issue, because dogs being taken to a veterinarian may be sick, and a veterinarian can't certify that such an animal is free of disease. The report states that "limited exceptions" will be made for the health certificate and rabies vaccination certificate for dogs imported for veterinary care. What "limited exceptions" means and how quickly an exemption can be obtained may determine whether this will impact the availability of veterinary care in some border regions.
Overall, more scrutiny of dog importation makes sense, particularly dogs being imported from developing countries where a variety of imported or exotic diseases may be present. However, these rule changes won't necessarily have an impact on some of the import-associated disease problems that have occurred recently. The current changes only involve dogs imported for resale, research or veterinary treatment. Importation of dogs for research is presumably uncommon and research colonies have pretty strict rules, so I doubt there's a lot of risk there. I also think it would be quite rare for dogs from high risk areas to be imported for research. Importation for veterinary care is also pretty uncommon and I'm not aware of it being implicated in imported disease. I don't know how often dogs are imported for resale, and this may be the area in which these changes have the biggest potential impact. Whether a dog from a Canadian or Mexican puppy mill is any higher risk to other dogs and the public than dogs from (much more common) American puppy mills is debatable. It would be nice to see a proper risk assessment that indicates which situations are the highest risk.
A recent case of canine rabies in France showed yet again the risks posed by illegal importation of animals. This case is somewhat unusual since it seems to involve ignorance of the rules and lax enforcement, compared to rampant animal smuggling, but the end result was the same.
The animal in question was a puppy that was brought to France by a family that had been vacationing in Morocco. They found the puppy on July 11 and returned to France on July 31. European Union regulations require that imported dogs be vaccinated against rabies and microchipped. Neither was done to this puppy, and it was in fact too young to vaccinate against rabies according to standard protocols. The family traveled back to France by ferry and car, and either met no customs officials or at least no officials who asked any questions about the puppy.
They day after they returned to France, the puppy started to exhibit behavioural changes and progressive sleepiness, with subsequent development of aggression. Five days later, it was taken to a veterinarian and it died the next day. Rabies was confirmed a few days later, and testing of the virus strain indicated that it was of the Africa-1 lineage and closely related to strains previously isolated in Morocco.
An investigation into possible rabies exposure ensued. Typically, it is assumed that animals can be infectious for up to 10 days prior to showing signs of rabies. Often, this is extended by several days for added confidence and because it's not always possible to determine exactly when the earliest, mildest signs might have developed. In this case, they considered the period that rabies could have been transmitted to be from July 18 until the puppy's death.
Multiple people had close contact with the puppy. Three family members had been bitten, a clear indication for post-exposure treatment. One other person (a friend of the family, it appears) was also bitten and received treatment. Another person reported being licked on non-intact skin (i.e. an area of skin with a cut, abrasion or other break in the normal barrier) and was also treated. The attending veterinarian, who had been previously vaccinated, received two booster shots.
This isn't the first time that rabies has made its way from Morocco to France, and it's concerning that it was so easy for it to happen. Nine rabid dogs have been illegally imported to France from Morocco since 2001. In 2008, one such dog subsequently transmitted rabies to several other dogs, resulting in France losing its rabies-free status until February 2010. It's not surprising that no questions were asked of the family traveling from Spain to France because of the open nature of borders between EU countries, but the ability to enter Spain from Morocco with no flags being raised is a concern. Hopefully there's an investigation into how this puppy was able to get into Europe so easily and how to reduce the chances of this happening again.
A paper that will be published in the September edition of Emerging Infectious Diseases (Mead et al 2011) talks about the potential for dogs to act as indicators of Lyme disease activity and risk for people. The use of animals as sentinels for human disease is well established. Sometimes it's because animals are more readily affected. Sometimes it's because the disease is easier to diagnose in animals. Sometimes it's because getting access to samples from animals is easier than from humans.
Because of the distribution of ticks that transmit the causative bacterium (Borrelia burgdorferi) and wildlife that act as the reservoir, the occurrence of Lyme disease is highly variable geographically. Knowing the amount of Lyme disease activity in a specific region is important for understanding the role of this disease in humans, and for implementing preventive measures.
Like people, dogs can get Lyme disease. Dogs are NOT sources of human infection, but since both dogs and people get Lyme disease the same way (from Ixodes ticks), infections in dogs can indicate the potential for infections in people (and vice versa). Since dogs may be more prone to being exposed to ticks, and since ticks are most likely to stay on dogs for the 24 hours or so that is required for ticks to transmit the bacterium, dogs may be more likely to be exposed to Borrelia spp. in endemic regions.
That's the reasoning in the Mead paper which suggests that dogs, because of their potentially greater chance of exposure and tendency to produce a good immune response after exposure, might be good indicators of human Lyme disease risk. To examine this premise, the authors compared data about B. burgdorferi antibody levels in dogs to human infection data. (Note: These are two different things: In dogs, they looked at antibodies, which indicate exposure but not necessarily disease. In people, they looked at disease. It's not inappropriate to compare the two, but you have to be aware of what they were comparing).
Overall, they showed (not surprisingly) that there was a relationship between antibody levels in dogs and Lyme disease in people. Some key findings were:
When the percentage of dogs with antibodies against B. burgdorferi was <1%, there were extremely low rates of disease in people in the area.
- This makes sense since it would indicate that there's little or no transmission occurring in the area. Low levels of B. burgdorferi in dogs or people don't necessarily indicate that Lyme disease is active in the area, since some cases could have been acquired during travel, and false positive results are possible with current testing.
The risk of disease is generally low to non-existent outside the highly Lyme-disease endemic areas: Northeast, mid-Atlantic and upper Midwest regions of the US.
- These are the areas where ticks capable of spreading the bacterium are common and where the bacterium is resident in wildlife, so that's not surprising.
Where 5% of more dogs had B. burgdorferi antibodies in their blood, there was always an above-average incidence of Lyme disease in people in the state, with a lesser association at the county level.
- Again, this makes sense. If most dogs are exposed, more people are going to be exposed, and more people will develop disease.
In 15% of counties where dogs had a >5% rate of antibodies, people did not have above average disease rates. However, in half of them, the incidence of disease in people increased to above average in the following 3 years.
- This is quite interesting and perhaps the most important finding of this study. It suggests that monitoring rates in dogs may predict trends in people.
What does this all mean? Well, a lot of these results would be expected based on what we know about Lyme disease. However, the apparent close linkage between human disease rates and dog antibody rates, and particularly the potential that dog rates could predict human rates, is intriguing and could be useful. By routinely monitoring for antibodies in dogs, areas where Lyme disease might be on the rise or might be emerging in people could be identified, leading to more focused educational efforts directed at both the public and healthcare personnel. Getting the dog data (or at least getting good dog data) is perhaps the problem, since testing would need to be done on a subset of the dog population that's not biased and is of adequate size to say something useful. There are ways to do this, but it takes time and money to do it right. Taking advantage of blood samples collected for heartworm testing is one possible approach, but careful thought needs to go into what could be done and whether it would be better than more intensive surveillance of humans or ticks.
China has a huge canine rabies problem, with thousands of human rabies deaths each year. There are several reasons for this, including large feral dog populations, inadequate vaccination of pet dogs, differences in approach and access to veterinary care for pets, inadequate education regarding dog bite prevention, and presumably inadequate education of people and/or healthcare personnel regarding when and how to seek proper post-exposure treatment.
Periodically, the knee-jerk reaction of dog culling rears its head in China, despite the ineffectiveness of culling alone as a rabies control tool.
Recently, authorities in Guangdong province have banned ownership of dogs (in most situations) and given residents until August 26 to get rid of their pets. Dogs remaining at that time will be put down, except for dogs that are used to protect property worth ~ $750 000 (or more). Those dogs must be vaccinated and "kept locked up." (Why the same things (i.e. vaccination and confinement) can't be done with any other pet dog is unclear, since being owned by a rich person doesn't make a dog less susceptible to rabies.)
An expert from the Chinese Center for Disease Control summed up the issue nicely: "This [ban] is not scientific, not humane, and it will not last long. In short term, maybe it could be effective, but after that, people still want to keep dogs."
Culls don't work well. A cull can decrease the population of concern for a time, but it's extremely unlikely that it would reduce the population enough to have any longterm effect. Dogs can reproduce quickly and replace the culled animals in a short period of time.
What would make more sense?
- Widespread vaccination of pet dogs, to reduce the risk of exposure of people from pets that get infected from feral dogs.
- Widespread vaccination of feral dogs, to reduce exposure of people and pet dogs. Achieving high vaccination rates (>70%) in the feral population is a critical control measure, but can be very challenging.
- Education of people about dog bite prevention.
- Education of people about dog bite care, particularly ensuring that they seek post-exposure treatment if bitten by a feral dog or a dog of unknown rabies status that can't be quarantined for 10 days to ensure it's not rabid.
- Education of healthcare personnel so that everyone who needs post-exposure treatment gets it (and gets it done right).
- Education of public health personnel to ensure that the two points above get done right.
- Ensuring adequate supply of good quality rabies vaccine and antibody for post-exposure treatment.
Yes, these measures require more work than a cull, and to some degree they also require a culture shift in the approach to keeping pets, but if China really wants to start preventing the thousands of rabies deaths that occur annually, that's what needs to be done.
Close to a dozen dogs in the Big Bay area of Michigan's upper peninsula have been diagnosed with blastomycosis, an uncommon but regionally important disease. Blastomycosis is caused by a fungus, Blastomyces dermatitidis. It's a dimorphic fungus, meaning it exists in 2 forms:
- Normally, it lives in the environment in the mold form. This is the infectious form to which dogs (and people) can be exposed via inhalation, ingestion or contamination of wounds.
- The other form is the yeast form. This develops from the mold form once it gets into the body, and this is what causes disease.
Dogs that are infected with blasto are of minimal risk to others since they are carrying the yeast form, and the yeast form is not transmissible under normal conditions. There is only a risk of infection in rare situations, such as a bite from a dog that has the yeast form in its mouth, or if someone sticks themselves with a needle that was used to sample an infected site. The main issue with finding blasto in a dog is that it is an indication that the fungus is present in the environment in the area where the dog has been in the past few months. That means people who went to those areas may have also been exposed.
Knowing where blasto is present is important for diagnosing disease in people and animals. Blasto is also a great example of a disease when getting a travel history can be critical for diagnosis. In some regions, blasto is most common where people tend to vacation or have cottages. If a veterinarian doesn't know that a dog has visited a high-risk area, blasto may not be considered. Not asking about travel history (or not getting a clear answer) can significantly impact the ability to diagnose this disease, and early diagnosis and treatment are critical for getting a good response.
If you live in an area where blasto is present, avoiding it can be tough. Staying away from areas that have been associated with the fungus can help, but defining this is difficult because of poor reporting and the long incubation period. Staying away from soil is pretty tough to do as a routine measure, so people living in endemic areas have to be aware of the disease and ensure that proper veterinary care is provided if there are early signs of infection (e.g. respiratory disease, skin lesion, unexplained weight loss). People who travel to areas where blasto is present should make sure their veterinarian knows about the potential for blasto exposure in any animals that may travel with them.
Dusty, the dog who tested positive for Hendra virus exposure on a Queensland farm, has been euthanized. The owners confirmed through their Member of Parliament that their pet had been euthanized voluntarily, rather than waiting for Biosecurity Queensland to compel them to do so.
Based on publicly available information, this seems like an illogical and unnecessary response, as well as an unethical approach by the government because it did not explain the implications of a positive result when they ask for voluntary testing of the dog.
The family said Dusty was euthanized because "most recent blood tests confirmed that he carried Hendra virus antibodies, which meant he was able to shed the virus to other animals." However, that's false. If government officials told them that, that's incredibly frustrating, disappointing and concerning. Antibodies have nothing to do with being infectious. I carry antibodies in my blood to a wide range of viral diseases that I've had over the course of my life. That doesn't mean that I still have the viruses in m. The presence of antibodies simply means the body has been exposed and mounted an immune response.
All information that I've seen so far indicates that there's no evidence that the dog was shedding virus and therefore no evidence that it posed a potential infectious risk. Furthermore, an experimental study from 1994 showed that infected dogs did not shed the virus. So, unless there are new data that aren't being released, euthanasia is a completely unnecessary and illogical response, probably based more on fear of liability than any evidence or reasonable assessment of risk. It would have been better to quarantine and monitor the dog, to prevent unnecessary euthanasia and to learn more about this virus in dogs.
If evidence indicating a true risk of transmission of Hendra virus from pets exists, this information needs to be released so that other pet owners in Queensland know what the situation is. If not, more common sense needs to be used when dealing with this disease in such animals.
This Worms & Germs blog entry was originally posted on equIDblog on 01-Aug-11.
Neil Fearon and his family have lost three horses to Hendra virus, and are concerned about one other. They are now dealing with the implications of their dog, a Kelpie named Dusty, having tested positive for Hendra virus antibodies in its blood. As I mentioned in yesterday's post, the presence of antibodies in the blood of this dog, detected during voluntary testing as part of the outbreak response, only indicates that the dog was exposed to the virus. Viral shedding was not identified, suggesting that the exposure was a prior event and that an active infection was not present. Despite this, government authorities are requiring that the Hendra antibody-positive dog be euthanized.
Poor communication and mixed messages are often the cause of problems during outbreak management, and this seems to be the case here. Based on the news reports, there are some pretty concerning issues.
Testing of the dog was voluntary and the owner was not notified that euthanasia would be required if the dog tested positive.
- This is rather unethical. People need to understand the implications of outbreak control measures. It's not fair to have such an aggressive response to a voluntary test without proper notification.
Mixed messages are being given about the risk the dog poses to the family.
- Authorities want to euthanize the dog, indicating they must believe there is some risk. However, the owner is very concerned about his 11-year-old son who has slept with the dog in his bed for the last few weeks. Yet, ABC news indicates authorities reassured Mr. Fearon that the risks are minimal. If the risks are minimal from that type of prolonged, close contact during the period when the dog may have been actively infected, it's hard to justify euthanasia after the fact on the basis of the dog posing a risk to people or animals (especially when the virus is endemic in the bat population in the area).
- Why euthanasia is being required seems to be unclear. While fear of Hendra virus shedding makes the most sense, Queensland's chief vet has stated that the dog will be euthanized as a precaution because "As a result of that infection, it may make it aggressive." It seems rather strange to euthanize a dog because of concern that an infection (which may not be active) might cause aggression, with no evidence that disease will occur or that it can cause aggression in dogs. Quarantine and observation would make more sense. There are a lot more dogs that are prone to aggression wandering around Australia.
This type of action drives things underground.
- When overly-aggressive actions are used, and people either don't agree with them or don't understand them, faith in the system decreases. What's the likelihood that people are going to allow their pets to be tested now? I assume it's a lot lower now that they've seen what will happen. So, the ability to determine exposure of other species and the potential risks from other species will be impacted.
Hendra virus is not something with which to play around. It's a very serious disease and one must err on the side of caution. How far you err on the side of caution is the question, and it's a hard thing to determine. It's easy to be very strict when setting rules, and fear of liability or fear of making a subjective decision often override logical thought and discussion.
As a somewhat informed outsider, I have a hard time supporting mandatory euthanasia for a dog that has evidence of previous infection but no evidence of active viral shedding. Yes, no test for virus shedding is 100%, but a pretty high level of assurance can be obtained and the dog can be quarantined for further testing. There's no indication from laboratory studies that I know of that dogs (or other non-bat species) can become longterm carriers of the virus. The owners should be involved in the decision making process and be given enough information to understand the implications of keeping the dog, the risks that might be present, and what they can do to reduce the risks. Government authorities need to clearly state their concerns and the evidence supporting them. With that, it's easier to make a logical plan that protects the public but is also appropriate for the animal and its owners. If the risk is deemed to be real and/or the owners are not willing to accept some degree of risk, then euthanasia is reasonable.
"Kill the dog" is an easy knee-jerk response. I simply don't see the evidence supporting it. Is it possible that authorities have a true reason to be concerned? Sure, but if so, that indicates another communication problem. If there is really evidence that this dog is a concern, this needs to be clearly communicated so people understand what's happening and why such drastic actions are being taken.
This Worms & Germs blog entry was originally posted on equIDblog on 27-Jul-11.
Adding a new twist to the already very concerning situation in Australia, Hendra virus infection has now also been identified in a dog. It's been a bad year for Hendra virus in Australia, with larger numbers of cases of this highly fatal disease in horses in a geographic range that seems to be expanding. Spread by flying foxes (fruit bats), Hendra virus predominantly infects horses, but can be transmitted to people working with infectedhorses.
The Australian Animal Health Laboratory in Geelong has now announced diagnosis of Hendra virus infection in a dog. The dog is from a quarantined farm in Queensland where the virus has been identified in a horse. The dog was healthy and was tested as part of a standard policy to test dogs and cats on infected farms. It's great to see this approach being used, since it helps identify other potential sources proactively - something that is often overlooked in outbreak investigations that focus only on the main species that are already known to be involved.
In this case, the dog had antibodies against the virus in its blood. That means that it was exposed to the virus and mounted an immune response. It doesn't indicate whether it was exposed recently or in the past. Two tests for the virus itself were negative, suggesting that the dog's immune system eliminated the virus (or that the virus isn't really capable of surviving for long in a dog). This is a good news/bad news scenario.
- Dogs can be infected. It increases the range of known susceptible species.
- If dogs can be infected and shed live virus, then they could be a source of infection for other individuals, including people.
- The dog wasn't sick. This might sound like strange "bad news," but healthy carriers of infectious diseases are harder to spot and control than ones that are sick.
- The dog wasn't shedding the virus. That's critical since if dogs can be infected but not infectious (i.e. if they can carry the virus but not transmit it), then they are of limited concern.
- They have been testing farm dogs and cats as a routine measure, and this was the first positive. Infection of pets therefore must be relatively uncommon even on farms where the virus is active.
- The dog wasn't sick. While it's only one case and doesn't guarantee dogs won't be affected clinically, this might suggest that dogs just occasionally get exposed with no disease. Since it's highly fatal in other species, that's a good thing.
What should be done based on this?
- Probably not much more than should have been done before this finding, but it's a good reminder about the potential involvement of other species.
- Dogs and cats should be kept away from fruit bat roosting sites.
- Dogs and cats should be kept away from infected horses.
- If a farm is quarantined because of Hendra virus, dogs and cats should be tested and quarantined. Quarantining the animal while testing is underway helps reduce the risk of an infectious dog or cat (should that occur) transmiting the virus to people on the farm, or wandering away and exposing other people or animals.
- Animals of any type in areas where Hendra virus is active that get sick with signs that could possibly be consistent with Hendra virus infection should be tested.
This should also be taken as yet another reminder that infectious diseases are unpredictable. Considering the potential involvement of different species in a proactive manner as was done here is critical.
Image: Bay Horse and White Dog by George Stubbs (1724-1806)
This Worms & Germs blog entry was originally posted on equIDblog on 26-Jul-11.
A 73-year-old New Jersey woman has died of rabies after being bitten by an infected dog. The woman was visiting Haiti in April when she was bitten, and she developed signs of neurological disease in late June. Family members and healthcare workers are being assessed to determine whether they may have been exposed to rabies during care of the woman. If so, post-exposure treatment would be started.
Rabies is a devastating but almost 100% preventable disease. While rare in most developed countries, canine rabies is a huge problem internationally and kills tens of thousands of people every year. The main reason it kills so many people is because of inadequate access to proper post-exposure treatment or failure to seek medical care. Timely access to post-exposure care can virtually guarantee that a person won't get rabies.
Why this woman didn't get post-exposure prophylaxis (I'm making the assumption that she didn't) isn't reported, and it could be because of patient or healthcare factors such as:
- Assuming a minor bite isn't a big deal.
- Not thinking about the potential for rabies.
- No access to adequate heatlhcare.
- The physician not thinking about rabies.
- Inadequate or no supply of rabies vaccine (for post-exposure treatment).
All of these problems can occur. Education of the public and medical personnel, as well as ensuring adequate access to rabies vaccine, are critical to prevention.
More information about rabies can be found in the Worms & Germs Resources page.
A Chapel Hill, North Carolina woman is suing Orange County in response to quarantine of her dog because of possible rabies exposure. This lawsuit highlights some of the inconsistencies in application of current rules, along with some misunderstandings.
In February, her dog Russell was barking at something under her deck, and that something ended up being a raccoon with rabies. There's no evidence of a fight or contact, but it can't be ruled out. Because of this, the dog was considered potentially exposed. Russell was overdue for his rabies booster, so a strict six-month quarantine was required, and the county required that this be done at an approved facility, not in the home. (The alternative option was euthanasia.)
- The lawsuit is based on the inconsistent application of the rules by various counties. The owner is seeking permission to quarantine the dog at home. This is allowed in many regions, provided there is confidence that the owner is responsible enough to properly quarantine the animal.
- It's a reasonable argument that's based on subjective and variable application of rabies guidelines. Certainly, formal quarantine in a facility offers more containment. The question is when household quarantine is appropriate, in terms of the animal's risk of exposure and the ability of the household to properly quarantine the animal.
Some other highlights:
Russell was overdue for his rabies vaccine by 46 days.
- Dogs don't immediately go from protected to unprotected. Certainly, we want animals to be up-to-date on their vaccines, but some thought needs to go into dealing with potentially exposed overdue animals. The NASPHV Rabies Compendium states "Animals overdue for a booster vaccination need to be evaluated on a case-by-case basis (e.g. severity of exposure, time elapsed since last vaccination, number of prior vaccinations, current health status, local rabies epidemiology)."
- Knowing the age of the dog and the number of previous vaccines would help, but the news article reports vaccinations (plural), suggesting that he's been vaccinated more than once in the past. In a dog with a relatively low index of exposure that was only overdue by 46 days, it would seem reasonable to consider it protected and treat it as vaccinated (although it's hard to say this definitively based on a news report that doesn't give the whole story). It's a critical point because considering the dog up-to-date would only result in a 45 day observation period as opposed to a strict six-month quarantine.
The owner's veterinarian stated that research shows that an animal that is vaccinated regularly is protected for many years, if not a lifetime.
- Yes and no. Vaccination is quite effective and in most animals probably confers long-lasting protection. However, I'm not aware of research that really shows this. This isn't a disease where we have good research data about duration of effect of vaccination. I suspect that most dogs that have been regularly vaccinated are well protected. Most does not equal all, and with a disease like rabies, you have to be quite sure.
A rabies antibody titre was measured. This is a blood test indicating the level of anti-rabies antibodies. The veterinarian indicated that the titre showed Russell is currently protected from contracting rabies.
- Unfortunately, no. TItres tell you antibody levels, but we don't have good data about what is actually protective. Higher is better, but we can't say a certain number is absolutely protective. Back to the NASPHV guidelines: "Titers do not directly correlate with protection because other immunologic factors also play a role in preventing rabies, and our abilities to measure and interpret those other factors are not well developed. Therefore, evidence of circulating rabies virus antibodies should not be used as a substitute for current vaccination in managing rabies exposures or determining the need for booster vaccinations in animals". That statement was echoed by North Carolina's state public health veterinarian, Dr. Carl WIlliams.
This is a tough situation. In many circumstances, home quarantine is a reasonable option. It's easier on everyone involved, by not separating the dog from the household. It's also less expensive. However, it inherently comes with some degree of risk to the household and the community. It's only a reasonable option when it's certain that people will take "strict quarantine" seriously, and truly quarantine the animal. That's hard to assess, and regulatory bodies are presumably afraid of assuming liability should they allow someone to quarantine an animal at home and something bad happens (e.g. it develops rabies and exposes people in the household, the owners take it outside where it encounters other animals or people, it escapes...). Determining whether someone can and will properly quarantine an animal isn't easy, and those issues presumably lead some people to err on the side of caution, and require formal quarantine at an approved facility.
The easiest way to avoid all this: Ensure your pets are properly vaccinated.
The British Columbia SPCA has seized 71 dogs, including 43 puppies, from a Vancouver Island woman and is planning on recommending cruelty charges. The dogs were seized from Green Acres Kennels because of various health problems that were believed to be the result of bad breeding and inadequate care. Numerous congenital abnormalities were identified, strongly suggesting poor breeding practices. Other problems like infections and severe dental disease were found, including one dog that will need most or all of its teeth removed.
As reported by The Province, SPCA Manager of Cruelty Investigations Marcie Moriarty explained "A good breeder would never breed those dogs. It's not fair to the dogs and it's the public who suffers when they have to spend thousands of dollars on vet bills."
Owner Nancy Kitching responded with the ever informative "That's a bunch of crock. The dogs are not in distress."
There are a number of problems associated with buying animals from poor breeders. Beyond the ethics of supporting these kinds of practices, poorly bred and raised puppies tend to be at increased risk of various health and behavioural problems. They also may be at higher risk for carrying a range of infectious agents, particularly bacteria and parasites.
Here are some red flags when it comes to identifying problem breeders/puppy mills:
- Lots of dogs available at any time. Most good breeders rarely have puppies available on demand.
- No scrutiny of potential buyers. Good breeders want to make sure their puppies go to good homes. If the only thing you need to show to get a puppy is your wallet, that's a bad sign.
- You don't see all the dogs that are advertized and/or the parents. If there's a barn in the backyard, lots of puppies for sale and no dogs in sight, the dogs may be all caged out of the way. Ask to see the parents and the rest of the litter.
- They won't tell you the name of their veterinarian. A good breeder has a good relationship with a veterinarian. A bad breeder may do a lot of their own "vet" work (often with internet-sourced drugs and vaccines), shuttle between multiple veterinarians and have a poor reputation amongst the veterinary practices in the area.
Buying a puppy should be a 10-year-or-more commitment, so it's worth doing right. If someone wants a dog from a breeder, it's better to put the time, effort and potentially more money into doing it right, because a bad choice can result in lots of extra cost, frustration and heartache.
As for Ms. Kitching, she's not getting the dogs back because she can't afford the costs associated with covering the legal, boarding and veterinary costs. However, she has plans on offering laser treatment for dogs with skin problems (which sounds like practicing veterinary medicine without a license) and may still 'dabble' in breeding. Beware.
When it comes to public health concerns about staphylococcal bacteria from pets, most of the attention gets paid to methicillin-resistant strains like MRSA. That's not surprising considering how important MRSA is in human medicine. However, staph that aren't methicillin-resistant can also be a problem, since they can cause the same types of infections that resistant types can (they are just easier to treat). Another issue that often gets overlooked is staphylococcal food poisoning.
Staphylococcal food poisoning is one of the most common foodborne illnesses and results from growth of certain strains of staphylococci in poorly handled or stored foods. If staph get into food and the food is kept at improper temperatures, the bacteria can grow. If the strain of staph that's in the food is one that can produce enterotoxins, these toxins can accumulate in the food at high enough levels to cause food poisoning when eaten. In most cases, people are probably the origin of enterotoxin-producing staph that contaminate food, but pets are another possible source.
A recent study in Vector-borne and Zoonotic Diseases (Abdel-moein et al 2011) looked at enterotoxigenic staph in 70 dogs and 47 cats. Swabs were collected from the mouth, nose and wounds. Nasal swabs were also collected from 26 people. The researchers isolated enterotoxigenic Staphylococcus aureus (strains of S. aureus that possessed genes for enterotoxin production) from 10% of dogs and 2.1% of cats, as well as 7.7% of people. Most of the positive samples from pets were oral samples.
This study shows that dogs and cats can be potential sources of strains of S. aureus that cause food poisoning. Since the staph are often in the animals' mouths (and therefore presumably shed in saliva), animals can potentially contaminate food with these enterotoxigenic staph fairly easily, but it's unknown how often this occurs.
Prevention measures are pretty basic but should be considered, including:
- Keeping pets off kitchen counters.
- Discarding foods that pets have licked.
- Washing hands after pet contact, before handling food.
- Properly storing food, so that even if it gets contaminated with staph, the bacteria don't get the opportunity to grow and produce toxins.
- Photo from http://www.wagreflex.com/2009/06/taking-cat-ownership-to-the-next-level.html
Urinary tract disease is a common reason for use (and misuse) of antibiotics. In veterinary medicine, one thing that we lack is clear clinical guidelines (particularly regarding antimicrobial use) to help manage specific types of diseases. In human medicine, there are some excellent guidelines of this kind (e.g. the Infectious Disease Society of America guidelines) available for a range of diseases, and these can greatly assist with proper management of cases.
Because of the lack of veterinary guidelines, the International Society for Companion Animal Infectious Diseases has started a guideline development program. Using a committee of international experts in the fields of infectious diseases, internal medicine, microbiology and pharmacology, from both human and veterinary medicine, and extensive discussion, debate and revision, specific treatment guidelines are being developed for different types of infectious diseases. The first set, Antimicrobial Use Guidelines for Treatment of Urinary Tract Disease in Dogs and Cats, has now passed peer-review and the guidelines have been published in Veterinary Medicine International, an open-access journal available to all veterinarians.
To download the guidelines, you can also click here.
Using logic akin to "Chocolate cake? It has flour, eggs and milk. It's virtually health food. You should eat it every day.", AllPetNews.com has an article on its site entitled "Dog saliva has healing properties." The article focuses on potential beneficial compounds in saliva, with specific reference to a University of Florida (Gainesville) discovery of nerve growth factor (NGF) in saliva (although I can't find any reference to nerve growth factor in dog saliva on PubMed).
The article states "Wounds that were treated with NGF actually healed twice as fast as untreated wounds, indicating that if a dog does lick a humans wound, it could in fact lead to a faster recovery."
The problem here is taking some controlled research data and spinning it out of control. Putting synthesized or concentrated nerve growth factor on a wound in a controlled manner is different from putting saliva on a wound, which is also different from having a dog lick it. You have to consider the whole picture when evaluating potential treatments. For example, rubbing alcohol kills bacteria nicely but that doesn't mean it's a good idea to put it on a wound to prevent infection. It hurts and it damages tissue. While it may kill superficial bacteria, the tissue damage can ultimately increase the risk of infection.
While there are certainly some compounds in dog (and human) saliva that stimulate healing, those potential benefits need to be weighed against the potential adverse effects, particularly infection. The oral cavity of the dog contains billions of bacteria from hundreds of different bacterial species. Many of these are able to cause infection given the right circumstances. A wound helps create the right circumstance by breaking down the body's normal protective barriers.
The article does mention some dangers, although only with licking of deep wounds (a wound doesn't have to be deep to become infected), and concludes with:
"Although the healing properties outweigh the negative impacts there will always be a number of people that find it in their best interest to treat a wound by cleaning it with soap and water...."
- At this point, there's no evidence that the beneficial properties of dog saliva outweigh the negative impacts. In reality, people would be better off if they carefully cleaned wounds with soap and water. Licking may not cause a problem in many (or even most) situations, but it can lead to serious infection, and the lack of clear evidence of benefit alongside documented risks indicate that this is an inappropriate activity.
A report from India of apparent failure of rabies post-exposure prophylaxis raises a significant concern. Few details are available, but it is reported that the affected person is currently in a coma, and if that is the case, death is almost certain. This case requires careful investigation, given the almost invariably fatal nature of rabies and the assumption that proper post-exposure treatment is basically 100% effective.
From my standpoint, I'd want to confirm that:
- the person actually completed the proper treatment course (one dose of anti-rabies antibodies and a series of four rabies vaccinations over a few weeks) - the article says the course was completed but doesn't give details of what that entailed.
- proper antibody and vaccine were used.
- correct doses were administered.
- the antibody and vaccines had been handled properly (e.g. kept at required temperatures - which at times may be easier said than done in a country as hot as India).
If all of these factors are confirmed, I'd want to know whether the person had some other disease or a compromised immune system that might have prevented him/her from responding properly to vaccination.
If no underlying problem was present, I'd want to see some testing of the lots of antibody and vaccine that were administered to ensure that they were adequate.
The timeline from when the person was exposed to when he/she received the post-exposure treatment to when he/she developed clinical signs of rabies is also critical. Delaying treatment for too long can also result in treatment failure.
Undertaking such an investigation is very important because the cause for any treatment failure needs to be understood if at all possible to help prevent it from happening again.
In the same news article, another man is also reported to be in a coma due to rabies infection, because he failed to complete the full course of treatment. That's a more common problem and can be caused by lack of awareness of the importance of completing the full treatment course, inadequate communication with healthcare providers and, in some regions, shortage of vaccine.
These cases show that while post-exposure treatment is a critical aspect of rabies prevention, it shouldn't be relied on as the sole line of defense. Feral dog control, rabies vaccination of animals and education regarding bite avoidance are critical rabies-control measures that often get ignored.
An interesting study published recently in Veterinary Dermatology (Bartlett et al 2011) looked at bacterial contamination of ear cleaning solutions used on dogs at home. Ear cleaners are widely used by dog owners, but since the bottles the cleaners come in are used repeatedly and can have direct contact with the ear, there’s a chance for contamination of the bottle and/or its contents.
In this study, the researchers collected ear cleaner bottles from dog owners and cultured both the applicator tips and the contents. Bacterial contamination was detected on 10% of the bottle tips and in 2% of the solutions. The relative numbers make sense, since the tips are most likely to have contact with the ear. Regardless, this shows that a small but still reasonable percentage of bottles contain bacteria that could be inoculated into the ear.
Finding bugs is one thing, but determining if they are types that can cause disease is another. The researchers identified a few different bacteria, including Staphylococcus pseudintermedius, which is an important cause of ear infections. This isn't too surprising since the bugs that cause infection are typically those that are also normally found in (healthy) ears at low levels (and therefore the types of bugs with which cleaner bottles might have contact).
Expired ear cleaners were more often contaminated. This doesn’t necessarily mean that age leads to increased risk of contamination. It could just indicate that bottles that have been used more and over longer periods of time are more likely to become contaminated. Similarly, large bottles more often had contaminated tips, probably because of more overall use (and correspondingly more chance for contamination).
An interesting aspect was the finding that solutions containing Tris-EDTA had higher contamination rates. Tris-EDTA is a solution that is often included in ear cleaners as it has been shown to be useful for treatment of infections caused by Gram-negative bacteria.
What does this mean for people that clean their dogs’ ears? It’s hard to say. We don’t know whether a little bit of bacterial contamination poses a realistic risk. However, it’s reasonable to consider using smaller bottles and discarding them after they are used to treat a dog with an ear infection (as opposed to regular ear cleaning).
Dr. Andrew Peregrine, a veterinary parasitologist at the Ontario Veterinary College, presented some data about the types of Giardia found in dogs and cats in Ontario at this week's University of Guelph Centre for Public Health and Zoonoses annual meeting.
A lot of attention has been paid to Giardia types in recent years. That's because, contrary to earlier thoughts, it's now known that certain types (also called assemblages) of Giardia can infect multiple species while others are host specific (i.e. they only infect one species). This is very important because if a dog or cat is shedding Giardia in their stool, the type determines whether there is any risk to people.
In the Ontario study, 75 canine and 13 feline Giardia-positive fecal samples were typed. In canine samples, assemblage D accounted for 68% of samples, while assemblage C accounted for 31%. These two are dog-specific, meaning 99% of typed canine samples contained only dog-specific types and were therefore no risk to human health. The other sample contained assemblage B, a zoonotic type that infects humans and animals. In contrast, 13/13 of the feline samples were assemblage A, a zoonotic type of Giardia.
These recent Ontario data indicate a low risk of transmission of Giardia from dogs to people, but some risk from cats - at least in Ontario. It's important to note that there appears to be geographic variation in this trend. Other recent studies have reported similar results, with the predominance of dog-specific types in dogs. However, a few studies have shown a predominance of the zoonotic assemblage A in dogs. These have mainly been in low socioeconomic status areas with infrastructure challenges that could increase the chance of dogs being exposed to human feces. Therefore, it may be that in areas where there is good sanitation, dogs are most likely to get Giardia from other dogs. When there are sanitation challenges, dogs may be more likely to be exposed to human types. So, it's important to know trends in different geographic regions to understand the risk of transmission from pets to humans.
As many of you know, there was a large ringworm "outbreak" at the Newmarket (Ontario) OSPCA shelter in 2010 that led to a public outcry in response to plans to depopulate the shelter. In the aftermath of the event, an independent investigation was launched, headed by Mr. Patrick LeSage (former Chief Justice of the Ontario Superior Court) and Dr. Alan Meek (former Dean of the Ontario Veterinary College). The investigation involved a comprehensive examination of activities pertaining to the outbreak and shelter operations, in conjunction with relevant experts (disclosure: I was one of those).
The report of the investigation is now available, and covers important aspects such as whether an outbreak was actually present (short answer: no) and whether there were major problems in shelter operation (short answer: yes). Most importantly, it provides a comprehensive set of recommendations to improve the operations of the Newmarket shelter and OSPCA as a whole.
The report, in its entirety, was released today by the OSPCA and is available for download on their website. The report is on the site in multiple files: the main report is listed as "Index" and contains the ~90 page overview and recommendations. The expert reports, which might also be of interest, are tables D1-3, E, F and G.
I have no problem with people considering "alternative" therapies for the treatment of infections. I perform research on non-antibiotic alternatives and hope that results pan out in the field. I have problems, however, with people that use unproven alternative therapies in lieu of proven conventional treatment or stray from the "do no harm" philosophy.
I read an article on aromatherapy in pets that highlighted my concern. Someone can make Fluffy or Fido smell whatever they want (although my dog Meg's concept of what smells nice certainly differs from mine - she'd rather roll around on a decomposing carcass than a lavender plant). I don't think it's going to help, but it shouldn't hurt. This article went beyond that, though, talking about application of substances to treat infections. Putting tea tree oil into a dog's ear isn't aromatherapy, it's topical therapy.
Is it an issue of semantics? No.
Essential oils like tea tree oil have some powerful properties. Just because it's "natural" doesn't mean it's safe. We know that tea tree oil has antibacterial properties. However, we also know it can be toxic. There are reports of serious adverse effects in people from tea tree oil ingestion and I know of severe reactions in dogs (including 1 death) thought to be due to excessive tea tree oil application. Adverse effects can result from the dog ingesting the oil by licking it off its coat or from direct effects on the skin.
A research study presented by Dr. Becky Valentine at the 2011 North American Veterinary Dermatology Forum highlighted this concern. Her research showed that while tea tree oil was able to kill methicillin-resistant Staphylococcus pseudintermedius (MRSP), a leading cause of canine ear and skin infections, it was also quite toxic to canine skin cells. So, the cost-benefit of tea tree oil is unclear since it certainly has some toxic properties, particularly when compared to other topical therapies such as chlorhexidine, that are essentially non-toxic.
Additionally, in a good demonstration of "all pain, no gain," Dr. Valentine's research showed that grapefruit seed extract, another compound available over the counter, had no effect on MRSP but had significant toxic effects on canine skin cells.
What does this mean? It means that essential oils and any other alternative therapies need to be studied, just like any other treatment. We need safety studies to know they won't cause problems, dosage studies to know how to use them and efficacy studies to know if they work. Natural products can be quite powerful and potentially useful, but they need proper testing.
A 35-year-old UK man has died following a seemingly innocuous dog bite. He was nipped by the family's pet dog, not during an aggressive incident but just a playful, boisterous dog. Later, he developed a fever. He saw a doctor the next day and was told that he had influenza based on his clinical signs, but no testing was done. There's no mention about whether the doctor was notified about the dog bite or asked about animal bites or contact. (I wouldn't be surprised if that didn't happen.)
Unfortunately, the man's condition deteriorated and he was diagnosed with sepsis, which is an overwhelming infection of the bloodstream. A dog-associated bacterium, Capnocytophaga canimorsus, was identified as the cause. Both of the man's leg's were amputated because of the effects of the infection, after which he started to improve, but he later developed more complications and ultimately died.
A doctor explained, "These things are so unusual. It would have been like an unstoppable train – it just depends on how the body reacts." Infection with C. canimorsus is rare, and once it's underway, it can be difficult to control. However, this quote neglects the potential treatable aspect of the infection. For an aggressive infection like this, diagnosing it early is critical. If the doctor had asked about pet contact, asked about bites, noticed the bite, or if the person had mentioned the dog bite at the first visit, an astute physician may have thought about bite-associated infection and hopefully started proper treatment, before fulminant sepsis developed. This would be particularly true for certain high-risk individuals.
Capnocytophaga infections occur almost exclusively in high-risk people, particularly people without a spleen, but also in immunocompromised individuals or alcoholics. There's no mention of whether this person had any of these risk factors, but people who do should know that they are at high risk, see a physician if they are ever bitten by an animal (even if it seems like a very minor bite), and make sure their physician knows about pet contact.
Avoiding Capnocytophaga is essentially impossible if you have a dog. It's carried in the mouths of most (if not all) dogs, but it's typically not an issue. Human infections are rare but they are important because, like in this case, they tend to be very severe when they do occur. High-risk individuals need to know about this bug, make sure their physician knows about any animal contact they have, be proactive to avoid bites and other exposure to dog saliva, thoroughly wash any bites or wounds contaminated with dog saliva, and consult a physician after any bite, regardless of how mild it may seem. Pet owners shouldn't be afraid of Capnocytophaga, but they should be aware of it and various other bite-associated pathogens, do their best to reduce the risk of bites occurring (e.g. proper training of dogs (and kids)), and know how to take care of bites.
Today (like most days) I answered questions about the potential for transmission of methicillin-resistant Staphylococcus pseudintermedius (MRSP) between people and pets. We have a long way to go before we fully understand the issues, but research continues to progress and we're learning more and more. A recent study by Dr. Engeline van Duijkeren and colleagues from Utrecht University published in Veterinary Microbiology (van Duijkeren et al. 2011) steps up our knowledge another notch.
In their study, the authors enrolled 20 households that owned pets with MRSP infections. They went into the households and collected samples from the index pet (the one with the MRSP infection), other pets, people and the household environment. At the time of sampling, 10 of the infected pets had gotten over their illness while the other 10 still had active infections.
Some highlights of the study:
- 4/14 (36%) of other dogs and 4/13 (31%) other cats in the households were MRSP carriers. In households where the pet still had an active infection, an astounding 86% of the other animals were carriers. All these numbers are much higher than the expected baseline rate of MRSP carriage by healthy pets in households, giving strong support to the notion that MRSP is being passed between pets in households with an infected pet. From an infection control standpoint, it's probably reasonable to assume that a pet living with an infected animal is a carrier.
- MRSP was isolated from 2/45 (4%) of nasal swabs from people. This is not too surprising, since we know that MRSP (and its susceptible counterpart, methicillin-susceptible S. pseudintermedius (MSSP)) can be transmitted between people and pets. This study shows us, however, that even when there is apparent MRSP transmission going on between pets in the household, it doesn't seem to commonly involve people.
- MRSP was found in the environment in 70% of houses (and 90% of household where the pet was still infected). These are pretty big numbers but are not really unexpected, since if MRSP is in and/or on animals, it's bound to be found in the environment. Whether the environment is a potential source of human or animal infection isn't known, but it's something to consider.
This research gives more evidence that MRSP can be spread readily between animals but less so between animals and people. It could be because animals have closer contact with each other in a household than with people, but a bigger factor is probably that S. pseudintermedius is more adapted to living on animals than on people.
The ever-popular methicilin-resistant Staphylococcus pseudintermedius (MRSP) owner information sheet has been updated and can be found, along with info sheets on many other topics, on the Worms & Germs Resources page.
An important concept when dealing with infectious diseases is consideration of the risk that an animal has been, or will be, exposed to a particular microorganism. Some diseases vary greatly geographically, and something that's very important in one region may be rare or non-existent in another. Good veterinarians are aware of disease trends in their area and make informed decisions about vaccination and anti-parasitic treatments based on what's happening in the area. They also know which diseases are common and which are rare or non-existent.
But that only works if the pets stay in their "home" area. Traveling with pets can result in exposure to various infectious diseases they wouldn't normally encounter. If a veterinarian doesn't know a pet travels, they can't make proper recommendations for preventive medicine.
Additionally, travel history can be very important when evaluating a sick animal, since there may be diseases that need to be considered in a traveling pet that wouldn't be an issue with a local pet. However, it's easy to overlook or forget about travel history. Pet owners need to tell their veterinarians about "recent" travel with their pets. What does recent mean? It's hard to say. For some diseases, exposure within the past few days is all that's important. For others, it may be weeks or months. So, if you have a sick pet and have traveled any time in the past year with it, it's good to mention that to your veterinarian. It may have nothing to do with the current illness, but it never hurts to let them know anyway. In some situations, it may be the critical piece of information needed to trigger thinking about a specific disease.
Some examples of diseases that may be travel-related (at least to dogs in most parts of Ontario):
- Blastomycosis, a fungal disease, tends to occur predominantly in specific areas. It's not too common elsewhere, but travel to high-risk areas puts blasto on the list of possibilities in certain cases.
- Around here, there's no indication for heartworm preventive treatment during cold winter months, but that changes if the pet goes to areas where mosquitoes hang around all year.
- Some tickborne diseases have very specific ranges that correspond to their primary hosts and certain vector species (such as birds). In Ontario, ticks are currently quite geographically focused and many dogs have little risk of exposure. Travel to one of the tick hotbed areas changes that, and means that certain tickborne diseases need to be considered.
- Canine influenza currently seems like a non-entity in Ontario. We're still looking for it but haven't found it. It is present in some places in the US, and at times, is a big problem. Travel to a place experiencing a canine flu outbreak would be a good indication to consider canine flu vaccination.
What to do?
- If you travel with your pet, part of your pre-travel checklist should be an appointment with your veterinarian to go over anything that needs to be done, be it vaccination, deworming, flea control, heartworm preventive or anything else. (It's also a good time to make sure there's nothing else going on with your pet, because you don't want a pet health crisis en route.)
- If your pet gets sick and has traveled, make sure your veterinarian knows where you went and when.
- If you travel regularly, even if it's not long distances, it's good to discuss it with your veterinarian to see if anything is required for your pet. Even if you just go a couple of hours away to a cottage regularly during the summer, you may be exposing your pet to something different.
Earlier this year, there was a large recall of pre-packaged alcohol wipes made by Triad Group because of bacterial contamination and implication of the wipes in a large number of human infections. While alcohol is used as an antiseptic, bacterial spores are inherently resistant to the effects of alcohol and contamination with spore-forming bacteria can turn wipes into disease vectors. In the latest outbreak, alcohol wipes were contaminated with Bacillus cereus and implicated in the deaths of 7 people.
As an extension of the earlier recall, Creative Pet Products and MAI/Genesis (Veterinary Concepts) have recalled first aid kits marketed for use in pets and horses. In addition to the potential for contaminated alcohol wipes there is concern that the "sterile" lubricant jelly may not be so sterile, and could also be contaminated with Bacillus cereus. Additionally there is mention that the iodine pads could be contaminated with another bacterium, Elizabethkingia meningoseptica. (It sounds like they have some pretty major quality control issues. Not surprisingly, production at the plant has been suspended pending an ongoing FDA investigation.)
Anyway, anyone with one of these first aid kits should check to see if their kit is involved in the recall:
Alcohol prep pads – Kits affected:
10140 Horse Aid™ Kit
10145 Sporting Dog Kit
10148 Sporting Dog II Kit
10151 K9 First Aid Police & Military Kit
Brands: Triad or NovaPlus
All Lot Numbers
Iodine prep pads – Kits affected:
10140 Horse Aid™ Kit
10145 Sporting Dog Kit
10148 Sporting Dog II Kit
Brands: Triad or H&P Industries
Lot Numbers starting with 8, 9, 0, 1
The kits were distributed in the United States, Australia, the United Kingdom, Taiwan and Costa Rica.
If you have one of these kits, you should get rid of the affected items. For further details (and presumably how to get a refund) click here.
This Worms & Germs blog entry was originally posted on equIDblog on 09-May-11.
After the devastation caused by Hurricane Katrina, there were numerous efforts to rescue animals left homeless or ownerless. As part of this, some animals were shipped far away, including large numbers to the Northeastern US and Canada. It was a time-consuming and expensive endeavour by very well-meaning people, but was accompanied by much controversy. Beyond the concerns about resources spent importing animals into areas where there is no shortage of strays and limited resources to care for them, there were infectious disease concerns. These concerns were real because of the potentially high incidence of disease, high rate of carriage of certain infectious agents and movement of dogs to regions where these diseases are rare or absent. Anytime you get population migration (be it human or animal) in response to a natural disaster, you have the risk of those migrants spreading diseases.
A study published earlier this year in the Journal of the American Veterinary Medical Association (Levy et al 2011) characterized some of these concerns. The researchers tested blood samples from 414 dogs and 56 cats that were transferred from the Gulf Coast region within four months of Hurricane Katrina. They tested the samples for a variety of infectious agents.
Among the highlights in dogs:
- Overall, 74% of dogs had "evidence of previous or current vector-borne infections." That's a pretty high number. Current versus previous is important, since the animals are only an infectious disease risk if currently infected. At least some of the testing was aimed at detecting infectious organisms (indicative of active infection), not just antibodies (which may indicate active or previous infection), so there was clear evidence that many dogs had active and potentially transmissible infections.
- Bartonella, Borrelia (Lyme disease), Ehrlichia and Babesia spp DNA were found rarely, in less than 2% of dogs. These organisms are spread by certain types of insects, and a concern with moving infected dogs is that it might allow for introduction of the disease into a new population if there are insects capable of transmitting these infectious agents in the new area. Fortunately, these weren't common.
- Canine influenza antibodies were found in less than 2% of dogs. This is a more important finding since canine flu is quite transmissible. While the virus is present in various parts of the US, it's distribution is pretty patchy. A dog infected with canine flu that comes into contact with other dogs in a new area could easily be the source of a local or regional outbreak.
- Dirofilaria immitis (heartworm) antigen was detected in 49% of dogs. This is a major concern and was one of the big causes of controversy in some regions. Dogs that are infected with heartworm and untreated are sources of infection. If bitten by a mosquito, heartworm can be transmitted to the mosquito, and then to other dogs (and less commonly cats, and very rarely humans). Heartworm is quite uncommon in many regions, and there were concerns that the transfer of these dogs could result in local increases in disease. Recommendations were developed to reduce the risk of heartworm dissemination, but given the high rate reported here, it's likely they were not widely followed.
- 56% of dogs had antibodies against West Nile virus. This is an interesting finding but not really relevant from a disease transmission standpoint. It likely reflects heavy mosquito exposure. West Nile virus is pretty innocuous in dogs and cats, and infected dogs and cats cannot pass on the virus to mosquiotoes or other animals.
- Dogs infected with heartworm were more likely to be infected with West Nile virus compared to those not infected with heartworm - presumably an indication of mosquito exposure.
The concerns are summed up nicely in the paper's conclusions: "Cats and dogs rescued from the disaster region had evidence of multiple infectious diseases. The dispersal of potentially infectious animals to other regions of North America where some infections were not typically found could have contributed to new geographic ranges for these organisms or to underdiagnosis in affected animals because of a low index of suspicion in regions with low disease prevalence."
I'm not saying don't rescue dogs and cats during disasters. Personally, I have to question the wisdom of putting the time, effort and resources into shipping animals around the continent when pretty much every jurisdiction already has their fill of animals in need of care, but people have different opinions. What common sense and this study should tell us is that we need to think about the infectious disease implications of mass animal movement, particularly marginalized animals with questionable or unknown disease status. Any large scale movement of animals needs to be accompanied by careful assessment of possible risks, and measures to make sure animals are properly tested and treated so that they don't pose an undue risk to the regions where they end up.
Image: Hurricane Katrina on August 28, 2005 (NASA)(source: http://en.wikipedia.org)
Another recent incident highlights yet again problems with untrained or inadequately trained service dogs.
The incident in question occurred in March, when Ava, a 14-month-old German Shepherd "service animal," lunged at a six-year-old child who lived next door. It sounds like the dog was roaming free and attacked the girl on her property. There's some debate about whether or not the girl was playing with the dog (which doesn't really matter because a service dog shouldn't attack under circumstances like that, nor should it be roaming at large). Anyway, the girl suffered a serious bite to her face that required more than 100 stitches to close.
Ava was owned by a family whose nine-year-old daughter has cancer. The dog was "trained" to steady the girl when she's dizzy. That may certainly be a good role for a service dog, as there is a wide range of beneficial activities that proper service dogs can perform. However, real service dogs are highly trained and closely evaluated, with a significant effort dedicated to making sure the dog is properly behaved and does not pose a risk to others. That's the problem here. While Ava might have been good for this one particular child, it doesn't sound like there was any training to protect the public (and if there was, it was woefully inadequate).
Ava apparently also bit another child in the fall, compounding the concerns. A settlement between the neighbours has resulted in the dog being removed from the township, with no declaration that she's dangerous, but also nothing preventing the likely lawsuit to recover medical costs, if not more.
There's nothing good that comes from a situation like this. A young girl has lost her dog, another young girl has suffered a serious bite, and true service dogs - that play a critical role in the lives of many people - get lumped in with these untrained animals.
If someone wants and needs a service dog, it's important to facilitate that. At the same time, if someone is going to take advantage of the benefits of having a service dog (e.g. broader access) they need to have an adequately trained, true service animal. Too many "service animals" are just pets with basically no additional training, but serious training is required for the animal to both do a real job as well as to ensure that there is minimal risk to the public.
I received this question yesterday, pertaining to a potential therapy dog.
Valley Fever, also known as coccidioidomycosis, is a fungal infection caused by Coccidioides immitis or Coccidioides posadasi. These fungi live in the soil and are most common in the southwestern US, northern Mexico, and parts of Central and South America. They are part of an unusual group of fungi called "dimorphic fungi," meaning they exist in two forms. One form in found in the environment (soil). This arthroconidial form is the infectious form. The other yeast-like form is present in the body tissues during infection, but is not (or at least is very minimally) transmissible.
Disease from Valley Fever is rare in healthy people. These fungi are mainly a concern in people with compromised immune systems. When illness occurs, flu-like disease, respiratory disease, rash and joint pain are the most common signs, but disseminated infection (i.e. infection throughout the body) is a much more serious form of the disease that can occur.
Valley Fever is similar in dogs, with most dogs have mild to inapparent disease, and most sick dogs having vague signs and respiratory disease. Cats often develop skin lesion. Disseminated disease can also occur.
While coccidioidomycosis can occur in both humans and animals, the risk of transmission between humans and animals is extremely low. The fact that it occurs in both humans and animals is because both humans and animals get exposed to the same sources, not because they spread it between each other.
However, there is a slight risk that shouldn't be ignored. There are two situations that are of concern.
- Bites: There is one report of a bite-associated infection in a veterinary technician. The risk of infection after a bite from an infected animal isn't known, but anyone bitten by an infected animal should seek medical advice. Presumably, nothing would be done initially but there could be close monitoring for disease so that it can be treated early if problems develop.
- Veterinary procedures: Infection has been reported in a person performing a necropsy (autopsy) on an infected horse. It was thought that infectious endospores were aerosolized when an infected area was cut with a saw as part of the procedure, and inhalation of the fungus lead to disease.
There's also a theoretical concern with handling bandage material from infected animals. While the active infection would be caused by the minimally infectious tissue form of the fungus, it's possible that infectious arthroconidia could develop in a bandage.
People with infected pets have little about which to be concerned. The main risk (which is also very low) is infection from a bite from an animal with disseminated disease. Basic bite avoidance should minimize this risk, however medical care should be sought following any bite and people at high risk of serious infection (e.g. people with compromised immune systems) should take particular care when interacting with infected animals. If a pet owner has to change a bandage on an infected animal, they should wear gloves, double bag and immediately dispose of the bandage, avoid contamination of the environment during bandage changing and thoroughly wash their hands after completing the task.
Image: The infectious arthroconidia of Coccidioides immitis (source: CDC Public Health Image Library #476).
Plague has been identified in a dog and cat from New Mexico. It’s not surprising, since plague is present in some wild animal populations in that region, but it’s still noteworthy because of the serious nature of the disease and the potential for transmission to humans.
Plague is a bacterial infection caused by Yersinia pestis. It’s carried mostly be certain types of rodents in different regions of the world, including parts of the southwestern US. It’s usually spread by fleas that bite an infected rodent and then bite a person or other animal, but it can also be spread by close contact with an infected animal. Cases in cats and dogs are uncommon, but occur in areas where plague is present in rodents, when pets have contact with infected fleas or close encounters with infected rodents (or rodent carcasses).
The latest two cases were in Santa Fe and Rio Arriba Counties in New Mexico. No details were provided about the form of plague (e.g. bubonic, pneumonic), the suspected source of infection or whether there is concern about human exposure. Finding plague in a pet is a concern for a few reasons. It indicates that plague is present in wildlife in the area, and people could be exposed from the same sources as the pets (i.e. fleas, contact with live or dead wildlife). Also, transmission of plague from pets to their caretakers can occur, particularly from cats with pneumonic plague (respiratory tract infection). Knowing that a person has had contact with a pet with plague is critical to making a prompt diagnosis. According to the World Health Organization, plague continues to infect more than 2000 people every year.
The New Mexico Department of Health has made the following recommendations:
- Avoid sick or dead rodents and rabbits, and their nests and burrows.
- Keep your pets from roaming and hunting and talk to your veterinarian about using an appropriate flea control product.
- Clean up areas near the house where rodents could live, such as woodpiles, brush piles, junk and abandoned vehicles.
- Sick pets should be examined promptly by a veterinarian.
- See your doctor about any unexplained illness involving a sudden and severe fever.
- Put hay, wood, and compost piles as far as possible from your home.
- Don’t leave your pet’s food and water where mice can get to it.
- Veterinarians and their staff are at higher risk and should take precautions when seeing suspect animal plague cases.
Photo: The vector of Yersina pestis: a flea (click image for source)
There are a number of published studies regarding methicillin-resistant Staphylococcus aureus (MRSA) carriage by veterinarians, most reporting high rates compared to the general population. This is a concern because MRSA is an important cause of disease in both people and animals. Just having MRSA living in your nose doesn't mean you're going to get sick. Indeed, around 2-3% of normal, healthy people are likely carrying MRSA at this moment. However, if you are carrying MRSA, you are at increased risk of developing an infection under certain circumstances. In veterinarians MRSA carriage is also a concern because of the potential for transmission to patients (and potentially from those patients back to people).
- 0.9% in industry and government veterinarians (who have limited contact with animals)
- 4.9% in small animals veterinarians
- 11.8% in veterinarians with horses as a major component of their caseload
- 21.5% in equine veterinarians
These results are similar to some of our earlier studies, with carriage rates in small animal veterinarians being higher than would be expected for the general population, and carriage rates in equine veterinarians being very high.
Why do veterinarians have high rates of MRSA carriage?
There's no definitive answer but there are some likely causes. Veterinarians have contact with large numbers of pets and horses, and we know these animals can carry MRSA. Even if the percentage of dogs, cats or horses carrying MRSA is very low, when you multiply that by the number of animals a veterinarian touches every week, you can see how contact with an MRSA-carrier is pretty likely. Veterinarians also tend to have close contact with sites where MRSA can be found, such as the nose. This makes the chance of having contact with the bacterium itself more likely. An additional issue the often sub-optimal use of routine infection control and hygiene practices (especially hand hygiene), which may also increase the risk of MRSA transmission. Put all these together, and it makes sense that veterinary personnel are at increased risk.
Why do carriage rates tend to be higher in equine veterinarians?
It could be because MRSA is more common in horses than small companion animals. Another plausible explanation is the fact that the horse's nose (the most likely site for MRSA to be living) is commonly touched during examination and restraint, and horses have pretty big noses to start. Additionally, good hygiene can take more effort on some farms, as sinks and often even hand sanitizer are not as readily available as they are in a clinic.
More information about MRSA in companion animals can be found on the Worms & Germs Resources page. More information about MRSA in horses can be found on our sister site, on the equIDblog Resources page.
This Worms & Germs blog entry was originally posted on equIDblog on 19-Apr-11.
A month or two ago, there was a lot of press about the risks of pets sleeping in beds. It was in response to an article in the journal Emerging Infectious Diseases that didn't put forth any new information, but summarized a few diseases that could potentially be transmitted by pets. Unfortunately, the relative risk of those diseases wasn't really explored, and some media reports latched onto diseases like the plague, transmission of which can occur between pets and humans but the likelihood of this in most areas is essentially nil.
Anyway, an article at Scienceline.org has taken a more balanced approach towards the subject. One sentence perhaps say it best: "Many of those scare headlines, however, missed the main point of Chomel’s work: For most people, the risks are minimal, and there are easy ways to go about preventing pet-to-owner disease sharing."
I won't go into details here, since you can read the article yourself, but a key component is that pet ownership is never no-risk, but is usually low-risk. Basic hygiene practices and common sense can reduce the risks further. The cost-benefit needs to be considered, and while we can never completely eliminate the "cost" aspect, the benefits of pet ownership certainly outweigh the costs in the vast majority of households.
When I give presentations to veterinarians about infection control, I often talk about legal liability as one reason they need a good infection control program. I talk about the potential bad scenarios, such as someone getting an MRSA infection from an animal and then turning around and suing the vet. I usually say something like "I don't think it's happened yet, but you never want to be an index case". I may need to change that line now that a Texas veterinary clinic is being sued over a person's MRSA infection.
However, the lawsuit, filed April 4, isn't from an owner. Rather, it's from a veterinary assistant. The woman is suing the clinic, claiming they were negligent because they didn't warn her that she would be caring for an MRSA-infected animal. She claims that she contracted the infection on the job and that it "has physically impaired her for the rest of her life."
I know nothing about this case beyond what's in the link above, however it raises a few important issues and questions.
What does this mean for the veterinary clinic?
- I've been saying for years that the bar is being raised and clinics need a good infection control program, including training and education, to reduce infections of both pets and people.
- As awareness of zoonotic diseases and veterinary infection control increases, the potential for lawsuits may similarly increase.
What level of warning is required for veterinary employees?
- This varies with the type of person.
- A veterinarian shouldn't need to be informed that they will work with animals carrying zoonotic pathogens. If they didn't pick that up in vet school, they've got some other major issues.
- A veterinary technician should have a similar understanding of the risks and measures that should be undertaken to reduce those risks.
- Lay personnel are a different story. You can't assume a lay employee has any knowledge whatsoever about infectious diseases, zoonotic diseases or infection control.
- If there are minors in the clinic (e.g. co-op students, volunteers), you need to go even farther, and there should be written notification of parents of the risks, and measures that are taken to reduce the risks.
- In general, the less the veterinary education, the greater the need for clear and documented education about disease avoidance.
How do you prove this person acquired MRSA on the job?
- That's tough. Perhaps there was a clear link with a case. Even stronger would be showing that the human and animal MRSA strains were the same, but that's unlikely to have been done. Just because MRSA can be found in animals doesn't mean that MRSA infections all come from animals. Humans are thought to be the source of the vast majority of MRSA infections and pets, and while pets can potentially spread it back to people, this is ultimately a human disease. People pick up MRSA all the time in the general population, although the percentage of people who carry it at any given time is still low.
- MRSA carriage rates have been shown to be higher in veterinarians than in the general public in a few different studies. I think it's clear that MRSA exposure is a risk of veterinary practice. However, proving that an individual infection came from a pet in a clinic is still difficult.
How can vet clinics reduce the risk of MRSA (and other) infections, as well as lawsuits?
- Have an infection control program in place.
- Make sure infection control practices and policies are written down.
- Make sure all employees are appropriately trained and document the training.
- Make sure people follow all of the required protocols.
Infection control isn't rocket science. At its heart, it's the application of some very basic practices. Infection control hasn't had a high profile in companion animal veterinary medicine in the past, but things are changing (albeit slowly). Available resources can help veterinary clinics implement a decent infection control program with minimal effort. A good resource is the document Infection Prevention and Control Best Practices for Small Animal Veterinary Clinics, which is available (free) for download on the Worms & Germs Resources page.
Heartworm is a parasitic infection (primarily of dogs) caused by Dirofilaria immitis, which is spread by mosquitoes. In areas where the parasite is present, the standard recommendation is for preventive treatment of dogs during the mosquito season, and annual testing to make sure they don't have the disease. Numerous types of heartworm medication are available, and there's been considerable debate about the potential for emergence of heartworm resistance.
In some areas, there have been increasing numbers of reports of apparent failures of heartworm preventive medication. These cases can sometimes be explained by factors such as poor compliance (e.g. the owner forgot to give the medication or did not give it properly), unnoticed vomiting/regurgitation of oral medication, or encountering an infected mosquito outside of the normal transmission period (i.e. in areas where it's a seasonal issue and medication is therefore not given year round). However, not all cases have clear explanations, and truly resistant heartworms have been identified.
Most of the concern has been focused around the inadvertent discovery of the "MP3" strain. For companies to be able to state that their product is effective against heartworm, they have to prove it in experimental studies using recent strains of the parasite. When the MP3 strain was used to test a potential new drug, they found out that it was actually resistant to the standard treatment.
A study in Veterinary Parasitology (Blagburn et al 2011) describes further testing that was done on this strain. The authors showed that only one of the four medications tested (imidacloprid/moxidectin) provided 100% protection in experimentally infected dogs with a single treatment.
At this point, there's limited information about clinical cases of resistant heartworm, and most of the anecdotal reports come from the central US. The MP3 strain itself was found in a dog from northeast Georgia in 2006. A big question is whether this is:
- a small, focal, regional issue
- a regional issue that's going to expand
- a wider but unidentified problem in many areas
There's no way to know for sure without surveillance, but it is cause for concern.
What does resistant heartworm mean to the average dog owner?
I think it means the days of being able to justify not testing dogs annually, even if it's certain that all heartworm medication has been given religiously since the last test, are over. Skipping annual testing was always a bit of a tenuous argument anyway, because of the potential for a dog to vomit or regurgitate oral medication, or to encounter an infected mosquito while not on medication, and it's even weaker now that resistance might be an issue.
Why is heartworm testing more important now?
It's important for two reasons. One is to make sure that heartworm is promptly diagnosed if it is present. This allows for earlier treatment before the parasites cause more damage. The other reason is to get information about whether resistant strains might be emerging in an area, which is helpful for the broader dog population. We have little information about the distribution of resistance, but if veterinarians start seeing heartworm cases in animals that have been properly treated with preventative medication, it's an indication that resistance might be developing in the area.
At this point, people shouldn't get too concerned about resistant heartworm, but we need to pay attention to the issue in case it increases or is in fact more widespread than we realize. Ongoing surveillance in different areas is needed to determine the scope of the problem, in terms of both the prevalence of resistant parasites and the impact on animal health. We need to be careful not to overreact, but at the same time we need to figure out what's going on. Pet owners need to have conversations with their veterinarians about the need for heartworm prevention in their pet, and the optimal approach to testing and prevention.
Leptospirosis is disease caused by several types of Leptospira bacteria. It's often called a re-emerging disease in dogs, because the incidence has been increasing over the past couple of decades in many areas. While the overall number of infections is limited, when it does occur lepto can cause serious disease, including kidney failure. It's also a zoonotic disease: lepto can be transmitted from sick dogs to the people who handle them. Infected animals shed the bacteria in their urine, and when the urine comes in contact with broken skin or mucous membranes (mouth, eyes, nose), transmission of infection can result.
Canine vaccines against lepto are available. In the past, lepto vaccination hasn't been all that popular because the vaccines tended to have a higher rate of side effects compared to most vaccines, and the types of lepto that the vaccines targeted were often not the most important types causing disease. This has changed more recently as newer vaccines have become available. These vaccines seem to have low rates of adverse effects and provide protection against the four types of lepto that tend to be the most important. These vaccines have also been shown in research studies to protect against disease and to reduce shedding of the lepto bacterium in urine (thereby decreasing the risk of transmission to other animals or people).
Lepto is not among the "core" vaccines that groups say all dogs should have. That's because the risk of lepto exposure varies greatly between regions and dogs. The key thing to consider when deciding whether or not to vaccinate is what each individual dog's risk of exposure is. The main reservoir of lepto is wildlife such as rats and raccoons. If infected wildlife are in the area, they may be peeing out lepto and contaminating the environment, particularly any type of standing water (lepto loves to live in warm, wet environments).
In the past, much of the concern has been focused on dogs that go out and swim in streams or ponds. The "poster child" for lepto has typically been the Labrador Retriever that goes out gallivanting in the bush, but that may be changing too. When you consider where wildlife such as rats and raccoons live and how high the wildlife infection rates can be, remember that these pests can be present in urban areas in incredibly large numbers. Living in a city does not make a dog safe from exposure to lepto. In fact some urban areas, with large numbers of wildlife crowded into high-traffic areas like parks, are probably higher risk than rural areas.
Deciding on vaccinating requires an understanding of how common lepto is in the area and whether there is a risk of exposure for the individual animal. This is a disease for which a veterinarian's understanding of disease patterns in an area (including any specific areas that be particularly high risk) and the types of possible exposure of the dog play a big role. There's no "one size fits all" recommendation for lepto vaccination.
The title of this post describes a very basic concept, but one that is sometimes forgotten or hard to follow. The key point is that the goal of treating a sick pet is to make the pet well. Getting well and getting "normal" laboratory data aren't necessarily the same thing.
A question that comes up a lot with MRSA, MRSP and other bacterial infections is "should my pet be tested after treatment to see if the bug is gone?" The answer is usually "no."
One reason to not re-test is just what I said above. The goal of treatment is to make the patient healthy. That doesn't necessarily mean that MRSA, MRSP or whatever bug is causing the problem needs to disappear. In fact, the bacterium that causes a given infection often remains (in smaller numbers) in or on the body somewhere. If it's a skin infection, the bacterium may still be present on the skin where the infection was. However, if the body is handling it well, then it's not necessarily a problem. We have to remember that every animal (and person) has multiple types of bacteria in or on it that can cause disease given the right circumstances. We're never going to eliminate them all. In fact, trying to get rid of all potentially bad bacteria would probably result in bigger problems.
Another concept that I emphasize a lot is only do a test if you have a plan for using the result. If you don't have a clear reason to do the test, and if the result won't impact your decisions or provide information you need in the future, then why do it? While a negative culture might be nice to see, it's not necessarily a guarantee that a particular bug is gone. Furthermore, a positive culture doesn't lead to actions that are any different from those that would be taken if the culture is negative in most situations because, as mentioned above, we're looking for clinical cure (getting better) rather than microbiological cure (getting rid of the bug). Rarely would we extend treatment or do anything different in response to a positive culture in a healthy animal.
The bottom line is post-treatment cultures are rarely needed. There may be some circumstances where testing after treatment is useful and where the results would lead to a defined plan of action, but these are few and far between.
Image: A Mueller-Hinton agar culture plate being used to test the antibiotic susceptibility of a bacterial isolate according to the Kirby-Bauer method. (source: CDC Public Health Image Library #10785)
In some situations, bringing a pet to work might be acceptable. In other situations, it's totally inappropriate. A UK dentist learned that the hard way.
Ian Hulme-Ribsy, a dentist, was found guilty of unprofessional and inappropriate conduct for several bad behaviours. One was that he brought his dog to his dental clinic and failed to clean his hands after handling it. That's a pretty blatant breach of basic infection control practices, in the sense of both having an animal in a patient care area (outside of a structured visitation program) and failure to use basic standards of hygiene to reduce the risk of disease transmission. (It's particularly troubling when you consider that as a dentist the man would be putting his unwashed fingers directly in patients' mouths.) It's pretty remarkable considering how much attention is generally paid to infection control in the dental world.
Also included in his list of bad behaviours was giving patients sedatives in liquid form without measuring. He'd just pour some into a plastic cup. Reckless disregard for dosing of sedatives is probably a bigger concern than the dog issue, but both show poor judgment.
Mr. Hulme-Ribsy didn't lose his license, but must practice with restrictions. "... Hulme-Rigby must work under supervision and take courses in record keeping, infection control and dental practice ethics. He must undergo annual infection control and record keeping audits, and is banned from administering benzodiazepine drugs, or any other sedatives. Hulme-Rigby’s case will then be reviewed to decide if he is fit to practise without restrictions."
I get this question a lot, from both pet owners and veterinarians. Typically, my answer is "no."
- The two big questions I always ask are "why do you want to know and what would you do with the results?"
Sometimes people want to know their pet's MRSA status to see if the pet was the source of their infection.
- However, MRSA in pets is typically associated with MRSA in humans, i.e. if a pet is carrying MRSA, it probably got it from the owner or another close contact. Finding MRSA in a pet after someone is diagnosed with an MRSA infection doesn't mean the pet was the source. More likely, the person got MRSA somewhere else and passed it on to their pet.
Sometimes, people want to know if their pet is at risk of an infection.
- Carrying MRSA presumably increases the risk of an MRSA infection, but likely only in animals already at risk of an infection because of underlying disease or other risk factors such as surgery. The risk to the average pet from short-term MRSA colonization is probably limited. Also, if the pet was identified as a carrier, we wouldn't be doing anything to eliminate carriage, since we have no idea if decolonization therapy is effective in animals, and it doesn't seem to be needed (because dogs and cats almost always get rid of it on their own). Therefore, it's hard to justify screening for this reason. If the animal was getting ready to undergo surgery, then that might change my answer.
For me, it's also very important to consider what you'd do with the results of any test. In general, in a household where a person has an MRSA infection:
If the pet tests negative, I'd say that it doesn't 100% guarantee that the pet is truly negative, since no screening test is absolutely 100% sensitive. Also, the test only tells you the status of the pet at the time of sampling. It could have picked up MRSA five minutes after the swabs were taken. So, a negative result means the animal is probably negative. Since it's not absolutely negative and since the pet would be at risk of picking up MRSA from the infected person after it was tested, I'd recommend close attention to hygiene around the pet (especially good hand hygiene and avoiding contact with the nose) to reduce the chance of the pet becoming colonized and to reduce the risk of MRSA transmission from pet to person if the pet was actually a carrier.
If the pet tests positive, I'd say that we certainly couldn't say the pet was the source of infection. More likely, it got it from the person with the infection. Since we know that MRSA carriage in dogs and cats is almost always transient, and that they will almost always get rid of it on their own if re-exposure is prevented, I'd recommend close attention to hygiene around the pet (especially good hand hygiene and avoiding contact with the nose).
Since my response to either result would essentially be the same, why test?
Efforts are better spent on good household hygiene practices and restricting contact with high risk sites. On both pets and people, this would include the nose, as well as any sites that are infected or sites that are prone to infection (e.g. skin lesions). That's going to be much more worthwhile and rewarding than testing the pet.
- Like all mammals, donkeys are susceptible to rabies virus but infections are not particularly common. Raccoon rabies has also be identified in the area, and a bite from a raccoon may have been the source.
- A York County woman was bitten by a kitten that ran into her house when the door was opened for someone else. The kitten bit her when she grabbed it to throw it (hopefully not violently) back outside... an understandable reaction but not what you want to do in a case like this. You need to know whether a wild animal that bites is rabid, and if it gets away, you can't test it. You need to get away from it but keep it contained until someone can come get it. The other problem with people getting rid of the animal is that they might not recognize the risk of rabies. In this case, the kitten was hit by a car after being removed from the house, which allowed for it to be tested.
Yet another report of a dog being exposed to rabies through contact with wildlife, then being euthanized because it was not properly vaccinated.
- An unvaccinated animal that has been exposed to a rabid animal has to be euthanized or undergo a strict six-month quarantine. A vaccinated animal only needs a 45-day observation at home.
- Encountering a manic bobcat isn't something I'd like to do, and a LaCrosse, Florida woman spent nine days in hospital after being attacked by one. The 25-pound cat was trying to get the family's cat, then lunged at the woman when she came outside the house, aiming for her neck. Her husband then shot it. They knew that the bobcat needed to be examined, and took the rather unusual approach of bringing it to the hospital emergency room with them (I'd love to have seen that). I don't imagine hospital personnel did anything, but Florida Fish and Wildlife Conservation Commission personnel came and got it, and later confirmed that it was rabid. (Image: Lynx rufus, US Fish & Wildlife Service)
Jones Natural Chews Company has recalled 2705 boxes of pig ear treats because of a "potential" for contamination with Salmonella. The recall was the result of a routine sampling program by the Washington State Department of Agriculture which revealed that the finished products contained the bacteria.
This shouldn't come as a surprise. Salmonella contamination of raw animal-based pet treats is nothing new, and contaminated treats have been implicated in outbreaks of human salmonellosis. There is a risk to pets as well, since Salmonella can cause disease ranging from mild to fatal. Typically, dogs that eat a little Salmonella don't get sick, but they may under the right circumstances, and even dogs that appear healthy can potentially infect people they are around. Handling the treats is also a risk to people, especially the very young, very old, pregnant women and people with compromised immune systems. Households with any individuals from these groups should avoid having any raw animal-based treats around (unless irradiated). Anyone having contact with treats (whether they're in a high-risk group or not) should wash their hands afterwards.
It's very common for kennels to require dogs be vaccinated against "kennel cough" before they are allowed in. There are two main reasons for this:
- Reducing the risk that a dog will bring kennel cough into the facility and spread it to other dogs.
- Reducing the likelihood that a dog will acquire kennel cough if someone else brought it in.
Overall, it's a sound policy, but it's far from 100% effective and it needs to be part of an overall kennel infection control program to work. Relying solely on vaccination to prevent kennel cough is a weak approach that can ultimately fail, particularly if other infection control practices are poor or if vaccination protocols are illogical.
Why isn't it 100% effective?
1) Kennel cough is a syndrome, not a specific disease. It can be caused by many different viruses and bacteria, often in combination. Kennel cough vaccines are typically targeted against Bordetella bronchiseptica +/- canine parainfluenza, two important causes of kennel cough, but not the only causes.
2) No vaccine is 100% effective. Vaccines help reduce the risk of illness, but they don't completely eliminate it. Some vaccines are better than others, and some animals respond better to vaccines than others.
3) Timing is another issue. One of the weak points of many kennel protocols is the requirement that the dog be vaccinated "before entry," or within a certain number of weeks or months. The problem with this is vaccines are not immediately effective. What often happens is people decide to board their animal at the last minute or realize the night before that they need their dog vaccinated, so the vaccine gets given a day (or less) before kenneling. The intranasal kennel cough vaccine (squirted up the nose) takes a few (3-5) days to be effective, and the injectable vaccine takes even longer (a week or more). Vaccination very soon before boarding, particularly for a dog that has never been vaccinated against kennel cough before, is unlikely to result in protection from infection by the time of boarding.
Requiring vaccination before boarding makes sense, but it's important to remember that:
- It's not 100% effective.
- It doesn't negate the need for a good infection control program.
- It needs to be given at an appropriate time to be effective.
The CDC's Morbidity and Mortality Weekly Reports has a short report about two plague cases in the US. Plague, while often thought of as a historical disease (the Black Death), is alive and well in wild rodents in some areas of the world, including parts of North America, and human cases continue to occur.
Here are highlights of the CDC report (in italics) with some extra comments.
Plague, caused by Yersinia pestis, is enzootic (present in the population, typically at a low level) among rodents in the western United States. Humans can be infected through 1) the bite of an infected flea carried by a rodent or, rarely, other animals, 2) direct contact with contaminated tissues, or 3) in rare cases, inhalation of respiratory secretions from infected persons or animals. In September 2010, the Oregon Health Authority reported the first two cases of human plague in Oregon since 1995 and the only two U.S. cases in 2010.
Both illnesses began on August 21. The patients, aged 17 and 42 years, lived in the same household and might have been exposed to plague by infected fleas from one of their dogs; that dog was found to be seropositive for Y. pestis by the passive hemagglutination-inhibition assay (dilution of 1:64). One patient acknowledged sleeping in the same bed with the dog during the 2 weeks before illness onset. Both patients had high fever and multiple bilateral inguinal buboes; one patient had hypotension, tachycardia, and acute renal failure and was hospitalized. A gram-negative rod with bipolar staining was isolated from a specimen of that patient's blood.
...25 days after specimen collection, the isolate was identified as Y. pestis... Both patients recovered uneventfully after empiric therapy with doxycycline and amoxicillin clavulanate potassium, respectively, although the latter is not considered effective in treating plague.
Plague is a Category A potential bioterrorism agent. Human infections are rare but can be life-threatening. The plague case-fatality rate depends on the clinical presentation (i.e., bubonic, septicemic, or pneumonic) and timing of antibiotic therapy initiation; if untreated, the case-fatality rate is >50% for bubonic plague and approaches 100% for pneumonic plague. Rapid laboratory identification can help guide therapy.
Sleeping in the same bed with dogs has been associated with plague in enzootic areas. Plague patients with no history of exposure to rodents can be infected by Y. pestis if their pets carry infected rodent fleas into the home. Veterinarians always should recommend flea control to dog and cat owners.
This is an example of a situation where pets can play a role in human infection while not being the direct source of infection. While direct pet-human transmission can occur, this typically involves situations where someone has close contact with a pet that is sick with the plague. Most often, this kind of transmission is associated with close contact with cats with pneumonic (respiratory) plague.
Key aspects of reducing the risk of pet-associated plague in areas where plague is, or may be, present, are:
- Preventing contact of pets with wildlife, living or dead.
- Preventing roaming of pets in the wild.
- Discouraging wildlife from living in or around homes.
- Keeping cats indoors.
- Routine flea control.
More information on plague and pets is available in our archives.
In Canada, rabies testing and surveillance is performed by the Canadian Food Inspection Agency (CFIA). National data for 2010 are now available and indicate there were a small number of cases in domestic animals, with more in wildlife, for a total of 123 cases.
Dogs: There were three cases, all in Saskatchewan.
Cats: Four cases, three in Manitoba and one in Alberta.
Horses: One rabid horse in Manitoba.
Cattle: One, from Manitoba.
Skunks: 60 cases, 33 in Manitoba, 17 in Saskatchewan and 10 in Ontario.
Bats: 48 rabid bats, most in Ontario (29) but also in BC, Alberta, Saskatchewan, Manitoba, Quebec, New Brunswick and Nova Scotia.
Foxes: Six from the Northwest Territories or Nunavut.
No rabid sheep, goats, raccoons (down from 58 in 2007), wolves or other species.
Manitoba seems to win the 2010 rabies prize, while Newfoundland and Labrador, Prince Edward Island and the Yukon had no cases.
As with any disease surveillance, these numbers underestimate the scope of rabies. For an animal to appear on the list, rabies had to be considered and testing performed. So, for wildlife, it's a massive underestimation of the number of cases, since most affected wildlife don't get tested. Wildlife testing (and testing in general) is typically only done when there has been the potential for human exposure. Domestic animal cases are probably a fairly close representation of the status of rabies in pet and farm animals, since it's reasonably likely that a domestic animal with rabies would be identified as such and tested (although certainly cases can be missed or neglected). As with wildlife, there is probably an under-identification of rabies in feral/stray dogs and cats, since testing would only be done on these animals if they are caught and if there was potential human exposure.
An Irish study has reported a high rate of Salmonella contamination in pig ear treats. Various earlier studies have identified Salmonella in pig ear treats, and human infections have been associated with contact with such treats. Recommendations for processing and handling of pig ear treats have been made and have hopefully reduced the likelihood of contamination, but there's no information about adherence to these recommendations.
In the most recent study, published in Food Research International (Adley et al. 2011), researchers purchased 102 pig ears from 4 pet shops in Limerick City, Ireland. Salmonella was detected in 28% of samples. A variety of different Salmonella types were found, including antibiotic resistant strains and types that are common causes of disease in people.
Interestingly, all of the contaminated treats were from 2 of the 4 stores. The two negative stores only sold treats sourced from within the European Union, and one of them only sold pre-packaged treats. The other two stores sold treats sourced from the EU and Brazil, and sold some in bulk bins. All positive treats were from the same distributor, and all were from bulk bins.
The high prevalence of Salmonella in these treats is concerning, particularly in light of standard guidelines for processing such treats and and EU regulation that if treats are not Salmonella-free, they must have less than 1 Salmonella bacterium per 25 g of product.
Contamination of bulk bin treats isn't surprising, as I mentioned in a post just the other day. Bulk bins allow for cross contamination, and a single positive treat (or a single contaminated hand going into the bin) can result in contamination of many other treats. Also, picking treats out of a bulk bin can potentially contaminate consumers' hands, and there's an additional concern that bulk bins are often kept at a level where young children (a high risk group) can access them.
Contact with Salmonella in pig ear treats is a risk, and people should wash their hands after any contact with a pet treat. Avoiding bulk bin treats is a good idea. Purchasing irradiated and individually packaged treats should also help reduce the risk. Unfortunately, stores do a lousy job of notifying people about the risk. As the paper states "We recommend public awareness advertising in pet shops to alert pet owners of the risks associated with pig ear pet treats and hygiene practices that should be followed."
Merrick Pet Care has recalled Junior Texas Taffy pet treats because of the potential for contamination with Salmonella. No illnesses have been reported but contamination of treats could pose a risk to both pets and owners.
Contamination of pet treats is not uncommonly reported, but the overall scope of the problem isn't well understood. Outbreaks of salmonellosis in people have been reported in association with handling contaminated treats. The impact on animal health is unclear. Most recalls are not associated with reports of animal illness, however it's possible that small numbers of sporadic cases of disease would not be identified or reported.
Recalls like this highlight the potential risk from any pet treat or pet food. You can never absolutely eliminate risk but you can do things that will probably reduce the risk and identify situations where there are greater concerns.
- Packaged treats may be lower risk than treats from bulk-bins, because a single contaminated item can lead to cross contamination of many others in these large bins.
- Individually packaged irradiated treats are presumably of little to no risk.
- "Human-grade," "premium" or other catchy descriptions have absolutely no meaning with regard to food safety.
- People should wash their hands or use a hand sanitizer after handling treats.
- Care should be taken when handling any animal-based pet treats, particularly in households that include people with compromised immune systems, infants, elderly individuals or pregnant women. In these households, particular attention needs to be paid to handwashing after contact with treats, or - better yet - avoiding treats (or at least non-irradiated treats) altogether.
Disinfectants aren't very important for your average pet owner. They are more of an issue for kennels and veterinary hospitals, but there are situations where disinfection of an area contaminated by a pet might be needed.This is particularly true for certain microorganisms that can persist in the environment for a long time. The "poster bug" for this in dogs is canine parvovirus.
As many pet owners know, canine parvovirus is a very hardy virus. It can live in the environment for years and is resistant to many commonly used disinfectants. Careful cleaning and disinfection may be required in some situations where an infected animal has been in an area, particularly if it has passed diarrhea. Choosing an appropriate disinfectant can be a problem.
Bleach is a good disinfectant and can kill parvovirus, but it's noxious and isn't a good option for many surfaces. At our hospital, we use accelerated hydrogen peroxide, an excellent disinfectant that can kill parvovirus, but it's more expensive. Many other disinfectants are out there, and many have claims on their labels that they can kill parvovirus. Unfortunately, many (or most) cannot. Some just have claims that aren't based on any evidence. Others provide somewhat misleading information that can confuse buyers.
A good example is a product I was asked about today. It was a quaternary ammonium disinfectant, a common class of disinfectants with variable and often poor killing effect on parvovirus. The product claimed to kill parvovirus, but on closer reading, there's a major issue. The disinfectant is supposed to be used at a dilution of 4.5 ounces per gallon of water, yet the parvovirus-killing claim was for a dilution of 18 ounces per gallon. So, it might really kill parvovirus, but if it only does so at 4 times the typical concentration, how useful is it?
Do people that are using it under the pretense that it kills parvo realize the issue? Probably not.
Would people actually use it at 4 times the regular concentration? Perhaps. But that makes it 4 times as expensive, at which point it might actually be cheaper to use a better disinfectant like accelerated peroxide.
Is this fair advertising? That's questionable. Yes, all the information is there, but you shouldn't have to read the fine print. If the product says it kills parvo, it should be proven to do so at the regular recommended concentration. If it only kills parvo at high concentrations, that should be written right alongside the statement that it kills parvo.
(Photo credit: Uwe Gille [CC-BY-SA-3.0], via Wikimedia Commons)
Cowpox virus is an example of a virus with a misleading name. It's place in history is from Jenner's observation that milkmaids who had been infected with cowpox were resistant to smallpox, leading to the use of cowpox (which causes very mild disease) to protect against smallpox (which is very, very bad). While cattle can be infected, they are not the true host of this virus, and infections in cattle are actually quite rare.
Various rodents are the true reservoir of cowpox. Other species can be infected from contact with infected rodents, including people and pets. Among pets, cats are most commonly infected, with most reports coming from central Europe. Cats may be infected more often because they may more often have close encounters with rats, but they are probably also inherently more susceptible to the disease than dogs.
Cowpox infections in dogs are very rare, but a case was recently described in Veterinary Dermatology (von Bomhard et al 2011). It involved a five-month-old Rottweiller from Germany that developed a very mild case of cowpox, with a single nodule on its muzzle. The dog recovered uneventfully, but it was an interesting case of a rare disease in a dog, and one that has some human health considerations.
People can be infected with cowpox from pets. In particular, infections from pet rats have been a problem in central Europe over the past few years. Outbreaks of human infections have been identified associated with widespread dissemination of infected rats from infected breeding or distribution facilities. Infections have also been reported from cats, and cats are a significant concern because of their ability to be a bridge between wild rodents and people, and because of the close contact they tend to have with people.
It's not surprising that disease was so mild in this Rottweiller puppy, and the risk to people in contact with the dog was probably limited because of the mild nature of the infection. No human cases were reported associated with this dog. Human infections from dogs have not been reported, largely because the disease is so rare in dogs and perhaps because when they are infected, dogs tend to have very mild disease. Cowpox is of minimal concern for most pet owners, but it something to be aware of when obtaining a new rodent, especially in regions where cowpox is an issue, and when dealing with cats in areas where cowpox is endemic in wild rodents. Some basic preventive measures include:
- Pet rodents and cats (especially newly obtained rodents) that develop skin lesions should be handled with care and be examined promptly by a veterinarian.
- Wild rodents should never be caught and kept as pets (for various other reasons, as well).
- Contact between domestic pets (particularly pet rodents and cats) and wild rodents should be prevented.
An upcoming article in the journal Emerging Infectious Diseases entitled "Zoonoses in the bedroom" has attracted some attention in the press. I haven't been able to access a copy yet, but will probably write about it soon. However, one article that was written about the paper had a pretty weak lead-in piece:
"Nikki Moustaki knew something was wrong when she got strep throat for the sixth time in a year. Her doctor wanted to take out her tonsils. But Moustaki, an otherwise healthy 30-something, was determined to uncover the source of the infection. "I saw a bunch of specialists, and one suggested my dog might be a carrier," said Moustaki, a New York City-based dog expert and trainer. "I had never thought of that. When you think of contagious diseases in dogs you think of rabies and ringworm, you don't think of strep." After four walks a day on the streets of Hell's Kitchen, Moustaki's dogs -- a schnauzer called Pepper and Ozzie, a schnoodle -- would curl up beside her in bed. Following her doctor's surprising suggestion, Moustaki started cleaning Pepper and Ozzie's paws with baby wipes after each walk. And she's been strep-free ever since."
While it's good to see the potential role of pets in human disease considered (since it's often overlooked), this is a example of the opposite end of the spectrum: implicating pets with absolutely no evidence, and actually, contrary to all available evidence. Saying that cleaning her dogs' feet prevented her from getting strep throat makes little sense on many levels. Firstly, if it actually made the difference, then she wasn't really getting strep from the dogs, it was coming into the house on the dogs' feet from the ground outside. There's no evidence the outdoor environment is a relevant source of strep. If strep was present on the dogs' feet, it would have to make it to her nose and mouth, and that degree of contact is hopefully unlikely (and if present, it would be associated with a lot bigger concerns that strep). Further, despite various studies, there is no evidence that dogs are even rare reservoirs of Group A Streptococcus, the cause of strep throat. Recurrent strep throat in people is caused by repeated exposure to infected people.
Like I said, it's good to see recognition of the potential role of pets. The next step, however, has to be looking for the evidence. It's not hard to find a few good references that talk about the role (or lack thereof in this case) of pets in human strep infections. Implicating the pet and recommending a rather bizarre foot hygiene regimen isn't really helping anyone.
Is it just coincidence that the infections have stopped in this woman? Probably. Recurrent infections don't tend to go on forever. However, maybe her increased attention to cleaning her dogs' paws also led to her paying more attention (consciously or otherwise) to her own hygiene practices, which would have probably played a greater role in disease prevention.
The situation occurred in March 2010, when a stray dog taken to a North Dakota animal shelter was diagnosed with rabies. An investigation was undertaken to look into human and animal exposure.
- Potential exposure was investigated in 32 people. Of these, 21 were determined to fit criteria for requiring post-exposure prophylaxis. This included nine shelter employees and one volunteer.
- Twenty-five dogs at the shelter were considered exposed. According to the report "In accordance with 2009 Compendium of Animal Rabies Prevention and Control guidance (1), the 25 dogs in the shelter with the rabid dog were euthanized." That's a somewhat misleading statement. Immediate euthanasia is not the only recommendation in this kind of situation, it's just one of the options. In a dog that has not been vaccinated (or whose vaccination status is unknown), euthanasia OR six months of strict quarantine is indicated. The decision to euthanize was probably a logistical one, not being able or wanting to quarantine this many dogs for such a long period of time. It's a reasonable decision given limited isolation capacity (and budget).
- Twenty-five other unvaccinated dogs that were adopted or claimed by their owners were also exposed. (Presumably, these were dogs that had contact with the infected dog, then went to homes before the rabid dog was diagnosed). Of these, 11 were euthanized, 13 were quarantined for 6 months at home, and one was 'unintentionally killed' (whatever that means). All euthanized dogs were tested and were negative for rabies.
A few issues were raised in the report:
Rabies vaccination of shelter personnel: "In addition, preexposure prophylaxis for animal shelter workers or other persons whose activities bring them into frequent contact with potentially infected animals should be considered, in accordance with Advisory Committee on Immunization Practices recommendations (6)" This is a complex issue. It would be ideal for all shelter employees to be vaccinated, and I'd love to see that done. The problem is actually getting it done. Shelters often have many employees and volunteers, and a very transient worker population. Getting all these people vaccinated is tough. Vaccinating short term, part time and temporary employees is tough enough, let alone volunteers. Cost is also an issue. Is it realistic to make people volunteering or earning low wages to pay the expensive cost of vaccination? Can shelters afford to pay for vaccination? What happens if someone doesn't want to be vaccinated? This is an ongoing issue in shelter medicine and one where there is no clear consensus. Shelter personnel clearly fit standard recommendations as being a group in which vaccination should be considered, but it's easier said than done.
Vaccination of animals: "First, all domestic animals should be vaccinated against rabies, in accordance with guidelines (1,8)." This is another issue that is very good in principle but tougher in practice. Rabies vaccination must be done by a veterinarian in most regions, and most shelters do not have a resident veterinarian. Getting animals vaccinated promptly after admission can be difficult. Ideally, shelters would have better and closer relationships with veterinarians, but it's quite variable (and an area that needs improvement). Vaccination would also not help much in some situations, since it does not result in immediate protection. Dogs that are vaccinated are not considered protected for 28 days. Therefore, even if they were vaccinated at arrival, some of the dogs in this situation would still be considered unprotected. Nonetheless, I don't want to dismiss the role of vaccination, and I think shelters need to significantly increase rabies vaccination rates. It's not a simple problem, however.
Contact in the shelter: "Second, animals without documentation of vaccination against rabies should be kept separate from the public, wildlife, and other animals to prevent transmission of the virus (5,8)." Another "good in principle, but have you ever been to a shelter?" statement. Shelters don't have lots of space. Having enough room to properly separate incoming, sick, and adoption animals is hard enough. Having to separate all those groups into rabies-vaccinated and non-vaccinated, or individually isolate animals, is going to be impossible logistically in most facilities. The concept of cohorting animals of different risks is excellent and can be improved on, it's just not possible to isolate all animals that are unvaccinated or of unknown vaccination status (i.e. almost every animal coming into a shelter). This is particularly true since they are not considered protected until 28 days after vaccination.
Infection control practices: "In this case, 36 dogs had to be euthanized because employees and volunteers might not have consistently followed the shelter's policy of preventing muzzle-to-muzzle contact between dogs." Compliance with infection control practices is an issue, and it could be improved. It's an area we're working on now.
Definition of contact: In this particular situation, a very broad definition of contact (that may result in exposure) was used. "Although the shelter's animal handling policies likely minimized contact among dogs, muzzle-to-muzzle contact could not be ruled out; therefore, BOAH and NDDoH recommended that all dogs present in the shelter from March 9--20 be euthanized." It's quite unlikely that any of these other dogs were truly exposed if this is the only kind of contact they may have had with the rabid dog. Balancing public health and animal welfare is difficult. Certainly, you need to err on the side of caution, but how far do you go? Quarantine would have been ideal because of the extremely low likelihood of exposure, however if it's not practical (or feasible or affordable) in a shelter situation, euthanasia may be the only option.
This was a bad situation but it's not surprising, nor will it be the last time it happens. A single rabid dog led to the euthanasia of 36 other dogs, and expensive (and probably stressful) treatment of 21 people. Shelter management can be improved to reduce the risk of this happening, but there's no way to absolutely prevent it.
Pseudorabies is one of those diseases with a really bad name (although it's a pretty bad disease too). It has nothing to do with rabies. Rather, it's caused by a herpesvirus; porcine herpesvirus 1. The name "pseudorabies" presumably came into existence because it causes neurological disease that, in some cases, can look like rabies.
Pigs are the reservoir of this virus, and it's a very important cause of pig disease in some regions. Spillover infections can occur in many different mammals, including dogs, cattle and sheep, and infections in these species are typically fatal.
Pseudorabies is not as widely distributed internationally as rabies, but it is present in wild boars in many regions, including many European countries. Infections in dogs are sporadically reported, typically in hunting dogs infected by contact with wild boars.
Recently, a case of pseudorabies (also known as Aujeszky's disease) was diagnosed in a dog in Luxembourg, the first diagnosis of the disease in the country since it was identified in domestic pigs in 1999. (Infections in wild boars were suspected in late 2009 but not confirmed.) Few clinical details are provided in the report to the OIE, beyond the fact that the dog died. Contact with "wild species" was listed as the source of the infection, which presumably was contact with wild boars.
Unlike rabies, pseudorabies is not a significant concern in people.
Many people think of rabies as a very rare disease primarily associated with wildlife, however canine rabies kills tens of thousand of people each year, making it a leading cause of infectious disease deaths in some areas. China is an example of such a region, and rabies is a serious problem throughout much of the country. For example, last month 33 people died of rabies in Guangdong province, according to the the Provincial Health Bureau. That means that there were more deaths from rabies than tuberculosis in the region (there were 80 deaths from AIDS, 33 from rabies and 14 from TB).
The frustrating part is that the vast majority of rabies infections can be prevented with basic medical care, consisting of timely administration of rabies post-exposure prophylaxis, and vaccination of both feral and pet dogs.
A few days ago, I wrote about tuberculosis (TB) exposure in several people who performed a necropsy on an infected dog. As part of that investigation, a cat in the household was tested and was also positive for TB. It was euthanized because of the public health concerns. A logical question from a reader was "Is there no treatment for animals, as there is with humans?"
Diagnosis of tuberculosis in an animal often results in prompt euthanasia, and some individuals and groups have euthanasia as a standard recommendation.
- We have no data about how to properly treat an infected animal.
- We have no data about how effective (or ineffective) treatment may be.
- It's not easy to test animals before or during treatment to see if they are shedding the TB bacterium (Mycobacterium tuberculosis).
- It's such a concerning disease in people that the inclination is to err on the side of caution when it comes to public health.
Is it an appropriate response?
In some circumstances, it probably is. In other circumstances, treatment shouldn't necessarily be dismissed. A major problem is the knowledge gap.
- We don't know whether infected animals pose any risk to people. Human-animal transmission can occur, but it's unclear whether animals can transmit the infection back to people.
- If transmission between pets and people occurs, we don't know what circumstances are involved. TB is not readily transmitted even between people. Short term exposure is not a major concern. It's likely that close and prolonged contact is required for transmission from pets, but we don't know for sure.
- We don't know if certain infected animals are higher risk than others, although there probably are differences. A dog with respiratory TB and active disease is probably a much higher risk than a dog with a localized TB abscess.
- We don't have easy and accurate ways to test pets for TB exposure and shedding. In people, sputum cultures are tested by having people spit in a cup. Getting a sample like that is obviously difficult in dogs. Collecting a good sample for testing is much more involved in pets and not amenable to routine testing (for research or monitoring).
- We don't know for how long to treat a pet with TB, or which drugs are optimal for use.
Treatment might be reasonable when there is an animal with mild disease (or no signs of disease), when the animal was infected from a household contact (meaning that some degree of TB exposure has already occurred in the household and the dog would probably only be a secondary source of exposure), when there are committed owners who are willing to embark on time consuming and expensive treatment, when owners are able to keep the dog away from other animals and people during the treatment period, and when there is an understanding that treatment may not work.
When might treatment not be a good idea?
- When the animal is shedding the TB bacterium in respiratory secretions.
- When the owners cannot afford prolonged and expensive treatment and monitoring.
- When the owners cannot be relied on the administer every dose of medication and make every required follow-up appointment.
- When owners cannot be relied on to keep the dog away from other dogs and animals (and people) during the treatment period (or at least during the initial period).
- When there are high-risk people in the household, such as people with HIV.
- When serious disease is present, such that the chances of recovery are low.
A recent paper about rabies post-exposure treatment in animals (Wilson et al, J Am Vet Med Assoc 2010) also contained some interesting information about rabies vaccine failure in pets. The study, which looked at data from more than 1000 animals in Texas from 2000-2009, mentioned a vaccinated 15-month-old cat that developed rabies. It had been vaccinated at 5 months of age and was not yet due for a booster, which would have been required at 17 months of age.
Rabies was also diagnosed in a dog and cat that had been vaccinated but were overdue for their boosters. Both initially received one dose of a 3-year vaccine, but they did not received the booster that is supposed to be given 1 year later. (Even with 3-year vaccines, pets are supposed to be given their first booster (i.e. their second dose of vaccine) after 1 year, before moving to getting boosters every 3 years). The dog was vaccinated 2 years and 9 months earlier. Twelve days after being exposed to a rabid skunk it was given a booster, but it developed rabies nonetheless and died 8 days later. The cat was vaccinated 2 years and 3 months earlier. It apparently did not receive a booster after it was exposed to rabies, and subsequently also died of rabies.
Another six dogs and three cats that were vaccinated developed rabies, but all of these were overdue for their booster or had been vaccinated less than 30 days before rabies exposure. These were therefore not considered vaccine failures.
This information should not be taken as an indication that rabies vaccination is not useful or that current vaccination protocols are inadequate. This involves a very small number of animals, and only one that was properly vaccinated. Rather, it should be a reminder that vaccination is not infallible and that the possibility of rabies cannot be summarily dismissed just because the animal has been properly vaccinated.
If an unvaccinated dog is exposed to rabies, the typical requirement is a strict six-month quarantine (with rabies vaccination one month into quarantine or one month before the end of quarantine) or prompt euthanasia.
Why? There has been only limited investigation of rabies post-exposure treatments in dogs. Ineffective post-exposure treatment could put the people around an exposed dog at risk of rabies exposure themselves. In the absence of convincing evidence, public health concerns trump animal issues.
A recent study published in the Journal of the American Veterinary Medical Association (Wilson et al 2010) sheds some more light on the topic. The authors reviewed records from rabies-exposed animals in Texas from 2000-2009, where a different post-exposure protocol is used for animals. In Texas, exposed unvaccinated animals are either:
- immediately euthanized, OR
- immediately vaccinated, kept in strict isolation for 90 days and given rabies vaccine boosters during the 3rd and 8th week of quarantine.
The authors reviewed the records of 1014 animals (769 dogs, 126 cats, 72 horses, 39 cattle, 3 sheep, 4 goats and 1 llama) that were treated with this modified protocol after exposure to another animal that was confirmed to be rabid.
None of the treated animals developed rabies.
An important issue to bear in mind is whether the animals in the report were actually exposed to the rabies virus itself, not just a rabid animal. There's no way to prove that any were actually exposed to the virus, however 29% had what was considered "direct exposure," and a further 38% had "probable exposure." Presumably, not all the animals were actually exposed, but even so, because they looked at so many animals, it provides more convincing evidence that the protocol is effective for preventing rabies. The only definitive way to figure it out would be to experimentally infect animals with rabies and then see if the post-exposure treatment prevents them from developing disease, something that is unlikely to be done for many reasons.
Immediate vaccination may be a key component of this protocol. Previous reports of post-exposure treatment failure have been cases where there was a relatively long interval (e.g. a couple of weeks) from rabies exposure to first vaccination. By that time, it's possible that the infection is too advanced, particularly since the typical incubation period for rabies in dogs is 21-60 days.
The Texas post-exposure protocol makes sense. It appears to be effective and requires a shorter quarantine period. Those are both important factors, and make post-exposure treatment a more viable option.
However, while this study provides evidence that this protocol may be effective, it doesn't mean everyone can just start using it. Regional laws regarding rabies exposure supercede these results, and unless the rules are changed, this approach may not be an option. Hopefully, regulatory officials will look at the results of this study and Texas' experience, and think about modifying their own protocols.
At the end of the day, however, it's still much better to have your animal properly vaccinated against rabies so that post-exposure treatment or quarantine isn't needed. Vaccination isn't 100% effective, but it's very good overall, and the mandated response to exposure of a vaccinated animal is much easier (on both the animal and owner) than for an unvaccinated animal.
Tuberculosis (TB) is a very important public health issue. Caused by the bacterium Mycobacterium tuberculosis, TB is likely the most widespread human infectious disease. Although it primarily affects people, it can rarely affect various animal species as well, including pets. The relevance of dogs to human TB is unclear: we know dogs can (rarely) be infected by M. tuberculosis, but it remains uncertain whether infected dogs pose a risk to their human contacts (presumably dogs become infected in the first place from one of their human contacts, who is therefore also a source of exposure to other people). There is little information available about this risk.
People working in the veterinary field are at increased risk of exposure to many infectious agents. For this reason, there are standard practices that are (or at least should be) used to reduce unexpected exposures. A good example of such an unexpected exposure and the consequences thereof is presented in a case report from Switzerland recently published in Veterinary Microbiology (Posthaus et al 2010).
The report describes a seven-year-old Ibizan hound that was referred to the University of Bern's small animal clinic because of lethargy and vague neurological abnormalities. The dog was originally imported from an unknown country in southern Europe and was adopted from a shelter at two years of age. The animal was ultimately euthanized after it became very ill, with severe neurological disease and respiratory arrest. On necropsy, masses were identified in the brain and liver, and infection with Mycobacterium avium complex was suspected. However, subsequent testing identified M. tuberculosis, triggering an investigation of all human and animal contacts.
Testing included a blood test called the IGRA, which detects people who are either infected or exposed. The test can't differentiate between a recent infection and a past infection/exposure, so a positive result needs to be interpreted in conjunction with an evaluation of the person's history, to determine if previous exposure is likely.
The Ibizan's two owners tested negative. None of the veterinary clinicians that worked with the dog before its death were positive (or more specifically, none were positive and the result thought to be related to exposure to the dog), including the three people who were involving in intubating the animal (placing a breathing tube - a potentially high-risk procedure in an animal with TB). In contrast, six pathologists who were involved with the necropsy were positive, including the three who were most closely involved. Two of these individuals had no apparent risk of previous exposure, so infection from the dog was suspected
Additionally, a cat that lived in the house tested positive. Because of the potential that the cat was infected and concerns about transmission to people, it was euthanized.
This case had some rather interesting findings:
- TB infection in a dog. Clinical disease caused by TB in dogs is rare, and signs can be quite vague, as in this animal. This was not a case of classical respiratory tract TB.
- Infection occurred in the dog well after its presumed time of exposure. The source of infection was unknown, but given the family's history, it is reasonable to suspect that the dog arrived in the country already infected. This shows how diseases like TB with potentially long incubation periods can catch you by surprise. The dog was treated with high doses of steroids initially, possibly triggering re-activation of dormant TB because of immunosuppression.
- Infection of people with TB while conducting a necropsy, demonstrating the occupational risks that can be involved in such procedures. The use of power tools to open the skull is commonplace in veterinary pathology, and may have played a role here by aerosolizing the bacterium. The institution has now changed standard necropsy practices to reduce the risk of subsequent exposures.
- There was no apparent infection of any people when the dog was alive. Presumably, it was not shedding much, or any, of the TB bacterium in its respiratory tract.
- Possible transmission of TB from the dog to a cat. However, it can't be stated with certainty that the dog and cat were not infected by the same unknown source after the dog was adopted. Testing was not performed on the cat after it was euthanized, so it is possible that it was not infected with TB, but with another related Mycobacterium.
This case doesn't indicate that we are dealing with a new issue. Rather, it is possible that there are many more dogs that are apparently healthy but infected with TB. These animals may pose little risk to people, especially if they don't have respiratory disease, but it's an area where information is limited. More attention needs to be paid to the risk of interspecies transmission of TB, how to identify it, how to reduce the risk, and how to manage infected animals. There's debate about whether exposed but healthy animals like the cat in this case should be euthanized because of the potential (but completely unknown) public health risk. Without good research data, we can't provide reliable answers to questions about the risks.
Image: Ibizan Hound (click for source)
Recently, I wrote about a potential outbreak of respiratory disease in dogs in Ottawa, Ontario. That "outbreak" seems to have died down (as is common, since outbreaks typically burn out over a period of time). However, I had a call today about a similar situation that might be occurring in the Whitby (Ontario) area. A few veterinarians are reporting a spike in "kennel cough" cases, including some dogs with severe disease. Whether this is truly an outbreak, and whether it's related to the Ottawa situation are both unclear, but it's concerning to get two similar reports over a relatively short period of time.
Situations like this can be caused by a variety of factors, including
- Movement of a known pathogen into a new area. Emergence of canine influenza in Ontario is my main concern in this category.
- Increased disease caused by typical pathogens that are present in the area.
- Hyper-awareness (and increased reporting), as opposed to a true outbreak.
Veterinarians and dog owners should be aware that something different may be going on in different Ontario regions, and consider more thorough diagnostic testing should respiratory disease be encountered. Including testing for canine flu would be a good idea. The two most common and effective ways to test for this disease are:
- Seroconversion: Detection of an increase in antibody levels against canine influenza virus in blood samples taken 10-14 days apart.
- Detection of virus by PCR: This molecular test looks for viral RNA. Testing can be done by certain labs on deep nasal swabs.
Testing does cost money (not much, but free testing isn't available) and it's sometimes hard to convince people that testing is useful, since it may not change the treatment for an individual dog. However, it is important to find out what caused the disease in order to explain why disease happened, to help prevent further disease in the individual dog, to determine optimal vaccination programs, and to provide important information for protection of other dogs in the community.
Heart attacks? Sure.
Mechanical problems? Absolutely.
Aggressive passengers? Yes.
But a 12-pound dog? Apparently so.
Mandy and her owner were flying from Newark to Phoenix on a US Airways flight. The dog was sedated and in an airline-approved cage under the seat, as per airline policy. So far, so good.
Then the dog started to become agitated. One report suggests it was because the sedation was wearing off. Whatever the cause, the owner tried to take the agitated dog out of the protective confines of its cage, into a noisy, crowded and potentially frightening new environment. Not surprisingly, when you take a dog coming out of sedation (and perhaps not completely aware of what's going on) and put it in a unfamiliar and confusing environment, bad things can happen.
In this case, it resulted in the dog biting the passenger in the seat next to the owner (who was trying to help calm down the dog). The dog then got loose and ran up and down the aisle of the plane, barking. A flight attendant who tried to grab the dog was also bitten.
The bites were minor, but the pilot decided to divert the flight to Pittsburgh so the bite victims could be treated (and presumably to get the dog off the plane before it bit more people). The people who were bitten eventually got back on board and continued the flight. However, Mandy and her owner did not, as "separate transportation" was arranged for them.
There's no information in the reports I've seen about the dog's rabies vaccination status, something that was hopefully queried by medical personnel. There's also no information about whether any action will be taken against the dog's owner. If the airline (and/or passengers) wanted to, I imagine a lawsuit could easily follow (especially given the litigious nature of US society). They might win, too, since the dog's owner deliberately broke clear rules that say the dog must remain in the carrier at all times. As a result of her action:
- Two people were injured.
- Medical costs were incurred.
- The plane had to be diverted, probably resulting in a large cost to the airline for additional landing fees, fuel, personnel time, and perhaps the need to move flight personnel or postpone flights because of the diversion. (I'd love to know an estimate of what such a diversion actually costs.)
- 122 passengers were inconvenienced and might have incurred costs from the delay as well.
...all for something that could have been avoided by leaving the dog in its cage.
The US Agency for Healthcare Research and Quality has published data regarding emergency department visits and inpatient stays involving dog bites. The comprehensive data from 2008 don't provide any real surprises, but they demonstrate yet again the importance of dog bites and the need to take further steps to reduce their incidence.
Among the highlights:
- There were approximately 316 200 emergency department visits due to dog bites in 2008, with 9 500 people requiring hospitalization.
- On average, 866 people visited an emergency department and 26 were hospitalized from a dog bite every day.
- Bites requiring emergency visits or hospitalization were much more common in rural areas, and males were more commonly bitten than females.
- Children 5-9 years of age had the highest rates of emergency department visits due to dog bites, while hospitalization rates were highest for 65-84 year-olds.
- The average cost of a dog-bite-related hospital stay was $18 200. More than half of people hospitalized required surgery.
- 0.5% of people hospitalized for a dog bite died.
This report involved hospital record data only, so there was no way to assess why the bites happened. Not all bites are preventable, but a lot are. When you consider the huge impact of these injuries, both physically and economically, it's clear that we have to do a better job preventing bites.
While the potential health risks to people exposed to dogs with Giardia have received a lot of attention (and concern), there's more and more evidence indicating that dogs pose a very limited risk to people. Giardia is a protozoal parasite that can cause diarrhea in numerous animal species, including people and dogs. It can also be found in healthy individuals, with several reports describing evidence of Giardia in the feces of approximately 7% of healthy dogs.
In the recent past, as easier-to-perform tests for Giardia became available, people sometimes tested healthy animals for the parasite, and then had to figure out what to do with positive but healthy pets. It has not been unusual for such dogs to be treated because of concerns about the potential for infecting people. However, it's becoming increasing clear that this risk is minimal.
The reason the risk is so low is due to the fact that not all Giardia are created alike. There are different assemblages (types) of Giardia, and not all types can infect all species. Knowing the types found in dogs and the types that cause illness in people can tell a lot about the potential human health risk. One more recent study has indicated that risk of animal-to-human transmission is likely very small.
In that study (Itoh et al, Veterinary Parasitology 2010), researchers tested fecal samples from 1794 puppies in pet stores in Japan. Giardia was detected in 23% of puppies. This is a pretty high number but it's not really surprising, as this highly mixed population of young, stressed animals would be considered high-risk compared to the average pet dog. All Giardia were assemblages C or D, which are dog-specific. Therefore, despite 23% of the puppies shedding Giardia, none posed a risk for human infection.
Yes, Giardia is a zoonotic infection, but the risk of dogs infecting people appears to be very low because dogs so rarely carry the types able to infect people. Beyond that, this is a "don't eat poop" disease, whereby the use of good hygiene practices to prevent inadvertent ingestion of Giardia from dog feces can reduce the risks even further.
The Swedish Veterinary Association has released an English version of their 2009 "Guidelines for the clinical use of antibiotics in the treatment of dogs and cats". It's a very comprehensive document that goes through various medical conditions and discusses antibiotic use recommendations. As concerns about antibiotic use and misuse increase, more organizations are putting the significant effort that is required into developing such guidelines, and they can be a tremendous asset. While there are still significant limitations in the available research needed to produce evidence-based guidelines, a combination of careful review of existing information and expert opinion can provide good guidance for treatment of infections in companion animals.
There are always a few disclaimers that need to be given when presenting antibiotic use guidelines:
- They are guidelines, not standards. They provide a general overview of the issues and how to manage most patients, but some patients don't read the book and need to be treated differently.
- Disease and drug resistance patterns vary between regions. These patterns need to be considered, particularly when considering guidelines produced in another area or country.
- Things change over time. As guidel