Most of the time, when we talk about the parasite Dirofilaria in animals, we’re talking about Dirofilaria immitis….heartworm. However, it’s not the only member of the family that is found in dogs and cats. Another one, Dirofilaria repens, is present in those species in many regions, and it can also spread to people (via mosquitoes).
A recent report from Belarus, highlighted in ProMed-Mail describes 21 cases of dirofilariasis caused by D. repens. Interestingly, this is a relatively new finding for the area, as the disease was not reported until the mid to late 1990s.
This parasite naturally infects dogs, cats, and a variety of wild carnivores like wild canids (wolves, coyotes, foxes). Mature worms live in tissues under the skin of a suitable host and there, they produce larvae (microfilaria). These larvae enter the bloodstream and can then be taken up by mosquitoes. If a mosquito feeds on an infected animal and then a person, it’s possible for it to transfer the larvae into the person. People aren’t natural hosts, and the parasite almost never develops into its adult state. However, as the parasite undertakes its futile migration through a person’s tissues, trying to find a place to mature, the body mounts an immune response. This results in local inflammation, typically with development of little nodules. Very rarely, more serious infections can occur…. Surgical excision of the nodule, +/- antiparasitic drugs is the typical treatment.
Heartworm prevention practices should also prevent establishment of D. repens infections in dogs. Control of the parasite in the dog population would be an important control measure, but if the parasite is present at high levels in wild animals, that would complicate things. Basic mosquito control and avoidance measures also make sense.
A recent rabies death in a Russian man highlights multiple screw-ups that led to the man’s death.
A 50 year old man in Smolino Kovvrosko, Russia was bitten by his cat the end of February.
- Problem #1. The cat was presumably not vaccinated against rabies. Vaccination is not 100% protective but it’s pretty likely this was an unvaccinated animal. If the cat was vaccinated, the chance of it contracting rabies would have been very low.
The man went to the local ‘medical assistant’, but rabies prophylaxis was not given.
- Problem #2. Here was the opportunity to initiate the discussion about rabies. This would involve querying the health status of the animal and quarantining it for 10d to see if it developed signs of rabies (which would indicate the need for post-exposure treatment). Those weren't done.
A few days later, the cat started acting strangely. A local vet euthanized the cat. Rabies was not discussed.
- Problem #3. Malpractice. Plain and simple. A cat with neurological disease needs to be considered a rabies suspect. Bite history must be queried before euthanizing an animal. If rabies testing had been performed or if rabies had been mentioned as a possibility, the man might have been treated.
At multiple timepoints, there were chances to identify the potential for rabies, but multiple people screwed up and the man died as a result. Rabies is virtually 100% preventable with proper post-exposure treatment, but virtually 100% fatal by the time someone develops disease.
The location of this case can be seen at http://www.wormsandgermsmap.com
Clinical guidelines are fairly new (and limited) in veterinary medicine, although they’re widespread in human medicine. Following up on recent guidelines for diagnosis of treatment of urinary tract infections in dogs and cats, a working group from the International Society for Companion Animal Infectious Diseases (ISCAID) has completed guidelines for the treatment of a common type of skin infection in dogs, superficial folliculitis (pyoderma).
No, not what I write (although I certainly get enough emails suggesting otherwise... and I'm sure another round of interesting emails is going to be coming at my way shortly).
In the past, and even sometimes still today, public health has had to deal with the phenomenon of having "chickenpox parties." These are events held by well-intentioned but grossly-uninformed parents who deliberately expose their kids to a child with chickenpox in order to "get it over with." Yes, the children will get chickenpox and yes, the children will become nicely immune to the disease thereafter. Most of the time, it’s not really a problem, but then there are the times when a child develops serious (and potentially fatal) complications from chickenpox. Or when one child picks up chickenpox and spreads it to a high-risk child who then develops complications. It went so far at one time that at least one person was selling lollipops laced with chickenpox over the internet (until it was pointed out that this was essentially a bioterrorism activity).
We now have the analogue being recommended in dogs. The basic idea is to take young puppies to an area where distemper virus or parvovirus is likely present, so the puppy will be exposed and vaccination won’t be required.
Sure, it might work.
- The puppy might get exposed to enough virus to develop an immune response but not cause disease.
- Or the puppy might get sick and require expensive veterinary care.
- Or the puppy might get sick and die.
- Or the puppy might do any one of the three above and also spread the virus to other susceptible dogs, whose owners didn’t make the conscious - and dumb - choice to purposefully expose their dogs to these potentially fatal viruses.
Do vaccine reactions occur?
- Of course.
Are animals vaccinated more often than needed?
- Probably. Vaccination intervals are increasing so progress is being made. However, confusing the debate about how long we can go between vaccines with whether dogs should be vaccinated at all is dangerous. There's no doubt that young animals need proper early-life vaccination to prevent these potentially fatal infections.
Does the benefit outweigh the costs?
- Absolutely. Vaccination has controlled some incredibly important infectious diseases.
- Choosing not to vaccinate in response to internet rumours isn’t logical and it puts lots of animals at risk.
- Also, decreasing population vaccination rates increases the disease risk to the dog and cat population overall, since fewer protected animals means more chance of disease circulating from animal to animal to animal before it can be stopped. It’s like the “Wakefield effect”: the surge in some vaccine-preventable diseases attributed to the now-discredited (and former doctor) Andrew Wakefield, whose flawed and unethical research fed the anti-vaccine movement with since-retracted data.
Vaccination of young animals is critical for the control of certain infectious diseases. Recommending otherwise is illogical, and when it’s done by people who should know better, it’s unethical. Hopefully this doesn't get to the point where we need to start tracking the animal equivalent of the Jenny McCarthy Body Count.
A cluster of Brucella canis infections has raised concerns in Calgary, Alberta, and hopefully will prompt more discussion about importation of dogs.
Brucella canis is a bacterium that can infect both dogs and people, although it’s natural host is dogs (more specifically, dogs that are not neutered or spayed). Human infections are quite rare but they can be nasty, and therefore need to be taken seriously. Infections are sporadically identified in dogs in Canada, but it seems to be a very rare disease overall, and most cases I’ve dealt with have been in dogs that were imported.
The latest incident involves identification of brucellosis in five dogs. The first case, not surprisingly, was imported, having come from somewhere in the southern US. Three other dogs also from the southern US had contact with the first dog. The fifth case, concerningly, was a local Alberta dog that had contact with the first dog. There seems to have also recently been another unrelated Brucella canis infection in a local dog that originated from Mexico.
The main human health risk associated with Brucella canis is contact with breeding animals, as the bacterium is shed mainly in vaginal discharge, placental and fetal fluids, semen and aborted fetuses. Contact with dogs that have given birth or aborted is the main concern. The bacterium can be shed in urine, but that seems to be less of a concern, particularly with otherwise healthy dogs. The risk to the general public is therefore quite low, but it’s important to try to control this bacterium because of the potential for serious human disease.
Brucellosis is just one of many potential disease risks with imported dogs. As I’ve discussed previously, there is little to no control over importation of dogs and little comprehensive guidance for people who are importing them. This is a big reason why we are seeing certain "foreign" diseases in dogs in Canada (e.g. leishmaniasis). We sorely need a comprehensive approach to dog importation to help reduce the risk of disease entry and help people who choose to import dogs do so safely.
This cluster of infections can also be found on our new disease tracking site, http://www.wormsandgermsmap.com.
A few questions were sent in by a reader regarding a recent post about rabies in a Texas animal shelter. They’re good ones so I thought I’d cover them here.
I'm a little confused by this. Weren't these shelter dogs vaccinated?
- Probably not. Many shelters don’t vaccinate against rabies. There are a few reasons for this:
- One reason is cost. From a shelter standpoint, rabies vaccination may even be considered of less importance compared to vaccination against diseases that are more common causes of illness in shelters (such as parvo).
- A big reason is that in most regions, rabies vaccines must be given by a veterinarian, and many shelters don’t have much veterinary involvement.
- Another consideration is that even if animals are vaccinated in the shelter, they are not considered protected until 28 days after vaccination.
- Yet another thing to consider is whether vaccination would have changed anything. Vaccinated dogs would still require a 45 day observation period. That’s much easier than a 6 month quarantine but still problematic and could lead to euthanasia for logistical reasons.
How exactly were these dogs exposed?
- Good question. It depends how the shelter was run and whether dogs were mixed together or socialized in groups. Sometimes, all dogs end up being considered exposed unless shelter personnel can definitively state that they know a particular dog didn’t have contact with the rabid dog. It’s often hard to say that with confidence, so by default they consider all dogs exposed.
What about vaccinated pets (dog and cat) that live in homes but go outside in suburban or rural environments? How do we know, for instance, that an indoor/outdoor cat hasn't come into contact with a rabid wild animal or feral cat? Do owners of indoor/outdoor cats really know where their cats go and what they do or who they associate with when they're out all day long? And, what about dogs that go out for their last potty break, unattended, in the fenced backyard at night when the wild critters come out? How do we know, really, that our pets haven't been exposed to rabies?
- We don’t. That’s an inherent risk in life, and a reason that we push for vaccination of all pets. Vaccination isn’t 100% but it will greatly reduce the risk of an animal developing rabies.
- This is also one of many reasons to make sure animals aren’t allowed to wander outside unsupervised.
A single rabid animal has lead to plans to euthanize 40 dogs at a Texas animal shelter. It’s very similar to a situation I discussed with vet students recently, and it’s one that raises a lot of emotions.
The brief version...one rabid dog was identified in the shelter.
- This means that consideration has to be given to who (people and animals) was exposed to the dog.
- If the shelter cannot state with confidence that a particular dog was not exposed to the affected dog (e.g. if they don’t strictly cohort groups and/or follow these practices), then it’s considered exposed. Fortunately, only 40 of the over 300 animals at this shelter were deemed potentially exposed. It’s not clear if this is because some dogs were considered unexposed or, more likely, that all dogs were considered exposed but cats were kept separately and therefore not exposed.
- A dog that’s been exposed to rabies needs a 45 day observation period (if properly vaccinated) or 6 month quarantine (if not known to be properly vaccinated) or euthanasia.
What are the odds that any other dogs were actually infected? Very low.
Is euthanasia, then, a reasonable response? Unfortunately, yes, in many situations.
This is where people start to get upset. Why euthanize these perfectly healthy dogs if none were likely going to get rabies and you can simply quarantine them?
At a basic level, I agree. But, when you think about it more, these actions make sense.
- Yes, the dogs could be quarantined, but how? That would involve keeping them in the shelter for 6 months, since fostering out rabies-exposed dogs would be hard to justify.
- If they quarantine them in the shelter, they essentially have to keep the shelter closed since it would make no sense to bring in more dogs (that would have to be strictly isolated from the others) and there’s probably little or no room for added dogs anyway.
- As a result, instead of being admitted to the shelter, the animals might be euthanized on the doorstep, since there’s often not a "plan B" for sheltering.
So, does it make sense to shut down the shelter for quarantine? That’s hard to justify. The net impact on dogs (both those in the shelter and those that would be admitted) plus considerations of shelter operations (e.g. lots of presumably unvaccinated people having to work with potentially exposed animals) need to be part of the discussion.
Unfortunate as it is, this is often the response. Ideally, there’d be a way to isolate these dogs and continue shelter operations (and pay for the extra costs associated with doing this). In the real world, this is rarely an option.
All of this could potentially have been prevented if the affected dog had been properly vaccinated by its original owners.
There have been a few reports of equine herpesvirus (EHV-1) neurological disease over the last couple of weeks and some other cases that have been less well publicized. Hopefully it’s all just been a blip on the radar and not a sign of things to come as equine events start to ramp up at this time of year. However, it would be good for racetracks to take these cases as reminders of the ever-present risk of EHV and the need to try to prevent problems.
Some tracks have taken this issue seriously and are working on infection control and outbreak response plans. In response to one outbreak, a Minnesota track is building an isolation area for infected horses and implementing a variety of infection control measures.
Too often, the response to EHV-1 is only reactive: when there's no immediate problem, people don’t do anything, and when there is a problem, people freak out (and it’s hard to do things right when people are freaking out).
We need a happy middle ground that includes a reasonable response plan (effective and realistic) and proactive measures to both reduce the risk of an outbreak and to facilitate response.
Racetracks are starting to understand the need, although the response is variable. The number of outbreaks and the potential implications of them (e.g. sick or dead horses, cancelled racing, horses banned from going to certain tracks) means that it is in the horse owners’ and tracks’ best interests to do things right. What constitutes "right" is a moving target, though, and some people just don’t want to bother.
You can virtually guarantee that there will be EHV-1 outbreaks at racetracks this summer. A limited number of horses will die but there will be massive disruption based on quarantines (sometimes reasonable, often excessive) and other fall-out.
While there’s no way to completely eliminate the risk of EHV in horses, there are many things that can be done to reduce the risk of an outbreak. Some are relatively cheap and easy, such as
- Ensuring that horses with signs consistent with EHV-1 are promptly examined and isolated
- Avoiding shipping horses from sales directly into racing barns
- Cohorting groups on tracks as much as possible to contain incidents to individual barns
- Fostering routine infection control practices by people who frequently move between barns like veterinarians, farriers and riders/drivers
Other measures may take more time, effort and planning, such as creation of isolation areas and development of clear outbreak response plans. One of the most important things that can be done, however, is improving communication and trust. Often the biggest challenges in outbreaks involve poor communications, such as unwillingness to report cases, egos and agendas that get in the way of effective and timely response, and various other related problems that can be fixed by people thinking and talking to each other.
Some tracks are doing a good job of thinking proactively. Many are taking the "head-in-the-sand" approach. Any track could run into a problem, but my money’s on bigger problems occurring at the tracks that don’t take this problem seriously.
Unfortunately, we’ll be talking more about EHV-1 outbreaks this summer.
“Seek and you shall find.”
That might be the simple explanation for why we’re hearing more about spillover of different types of flu viruses into dogs. Sporadic reports of dogs being infected by different flu viruses keep coming in these days, maybe we didn't get this reports in the past because people just often didn’t bother testing dogs when doing surveillance of flu outbreaks in other species.
The latest incident is a report of finding antibodies against the H5N8 avian flu virus in a dog on a South Korean farm. This H5N8 strain is different from the H3N8 canine flu strain that has become a true "dog-flu", having adapted to dogs following spillover from horses.
This potentially emerging H5N8 avian flu virus has caused a lot of concern in southeast Asia as it can be devastating to poultry farms. It doesn’t sound like the dog in this case was sick, but the suspicion is that the dog was infected by eating infected poultry.
Avian flu viruses are a concern because some avian flu types can infect people and cause very serious disease. They can also cause devastating outbreaks in birds. Mixing of avian (and other) flu viruses with human viruses is the biggest concern, as it could potentially create a new pandemic virus that retains its high mortality in people but spreads much more easily like regular human flu strains. Adding more species to the mix adds more potential routes for transmission and flu virus recombination. It's likely that dogs are of little to no concern here, and the dog was probably never infectious - it just got exposed, mounted an immune response and the virus died. However, it indicates the need to consider broader surveillance, involving various companion animal species, when investigation new influenza threats.
Actually, the title of this post should be “Obese cat attacks family after being booted in the rear as a disciplinary measure. Family freaks out but wants to keep cat.”
Oh, where to start.
1) A 22 lb cat is obese and there are obviously animal care issues.
2) Kicking a cat in the rear after it objects to having its tail yanked by a baby is hardly an appropriate training measure
3) A cat that will attack with enough vehemence to make a group of adults barricade themselves and call 911 has other behaviour issues.
4) A family that thinks a cat that has a history of aggression and that made them barricade themselves in a room and call 911 is still an appropriate family pet for a household with a seven-month-old child is delusional.
While there may well be more to this story than has been reported, it seems like the baby pulled the cat’s tail, the cat objected and scratched the child, the owner kicked the cat, the cat responded, and the owners ended up locking themselves in a bedroom and calling 911 saying "I kicked the cat in the rear, and it has gone over the edge, He's trying to attack us -- he's very hostile. He's at our door; he's charging us" as the cat screeched in the background.
Yet, after all that they apparently want to keep the cat, though they "definitely want to keep [the cat] away from the baby and keep an eye on his behavior."
Does this cat pose a major risk?
It’s hard to say. Probably not in most circumstances, but it can certainly be sent over the edge and respond very aggressively, something that has apparently happened more than once.
Should this cat be in this household?
Probably not. It’s in a household with a high-risk individual (the baby). Kids sometimes inappropriately handle animals, and this cat clearly doesn’t respond well to provocation. The owners don’t seem equipped to handle this properly. The cat might be perfectly fine in a household where it’s not provoked, but it doesn’t seem like a good fit for this household.
Can anything be done to prevent further problems?
A few things need to be considered. The first is a veterinary exam to make sure there’s not a physical reason for the cat’s response (e.g. is there a problem that made a little tail pull cause severe pain?). A consultation with a veterinary behaviourist (a veterinarian that specializes in behaviour as a result of extensive specialty training - not a self-proclaimed, untrained "pet psychologist" that the owners mentioned) would then be indicated to try to identify why this happened, and how (or whether) it can be prevented in the future.
While rarely (if ever) is there a situation where there should be no pets in households, there are situations where a combination of a certain pet and certain people doesn't fit. This is probably one of those.
Surprisingly (at least to me), I don't hear much about individuals suing other people because of infectious diseases in their horses (apart from sporadic situations involving veterinary hospitals). I'm not saying the increasingly litigious nature of society is a good thing, but I can see how lawsuits could happen given the costs associated with infectious diseases, the emotions that can be involved and the lack of a well-defined standard of care.
The potential for liability isn't necessarily a bad thing IF it motivates people to do what's right. While ideally it wouldn't take the threat of financial loss to properly motivate someone, it can be a useful argument. Our first strangles poster touched on social influences as a motivator (i.e. if you do something that causes other peoples' horses to get sick, you're not going to be popular). Our second poster (below) addresses the potential for liability, which I think is particularly real when people knowingly move horses from a farm with strangles, especially when they don't notify the new farm about the potential for strangles exposure and take appropriate precautions.
An outbreak of equine herpesvirus type 1 (EHV-1) neurological disease has occurred on an Oregon farm. At last report, five horses had tested positive for the virus (though it's not clear if all of them had neurological disease) and one had died.
EHV-1 outbreaks are not exactly rare these days. There's certainly more reporting of sporadic disease and outbreaks, but it also seems like there's been a true increase in outbreaks over the past 10-15 years. During my residency, we saw EHV-1 neuro cases not uncommonly, but almost always as single cases. Now, clusters like this are more common, for no clear reason.
Anyway, this outbreak appears to be contained, and it's good that there's been no movement on or off the farm in a while. This will likely end up being a sporadic, contained cluster on a farm with no broader implications. Since EHV-1 is very common, being found in the majority of horses, there's always some risk of disease occurring. That's one of the main challenges we have in understanding and controlling this virus.
Tracking of EHV-1, and other equine (and dog and cat) diseases will soon be available on Worms & Germs MAP. Stay tuned.
There's been a lot of press about strangles (Streptococcus equi) outbreaks in Ontario lately, including a biosecurity update from the Ontario Ministry of Agriculture and Food (OMAF). In some ways, it's surprising since this is an endemic disease and strangles is pretty much always causing trouble somewhere in the province. However, a little press is never a bad thing, if it can help get people to do what they need to do (but often don't do) to control this highly contagious equine disease.
A big problem with strangles control is the unwillingness of some people to admit they have cases and/or people knowingly taking exposed horses off the farm, thereby spreading the bacterium to other farms.
Along that line, here's our latest educational poster. As with all of our materials, feel free to print, copy, post or disseminate at will. A higher resolution version can be downloaded from the Worms & Germs Resources - Horses page.
There’s been some controversy in the past regarding allowing pets to sleep in or on the bed. I don’t get too worked up about it, since I think it’s very low-risk in terms of disease transmission for most pets and households, but a variety if reasons for prohibiting this practice have been given.
I haven’t previously heard the reason: “Don’t do it because you might think you’re petting your cat when you are actually mistakenly pissing off the rabid raccoon that’s dozing beside you.”
Maybe that should be added to at list.
A Massachusetts woman learned this one the hard way. The woman was asleep one night a few weeks ago and reached over to pet what she thought was her cat. Unbeknownst to her, the critter beside her was actually a rabid raccoon that had come into the house through a cat door. Unhappy at being disturbed (and with a less-than-functional brain from rabies), the raccoon attacked, jumping on the woman's face and biting her lip, refusing to let go. She managed to pry the creature off her face, whack it with her phone and call 911. Animal control caught the raccoon, which was subsequently euthanized and confirmed as rabid.
From a more serious standpoint, this case highlights one of the big drawbacks of having a cat door that allows entry and exit of any cat-sized animal. Keeping cats indoors is a good idea for the cat’s health, the family’s health and the wild bird population (and avoids the cat door issue entirely!).
I would have thought this would fall under the realm of common sense, but as the saying goes: Common sense is like deodorant, the people that need it the most don’t use it.
A recent report out of Scotland is warning people not to kiss their pet reptiles, in response to four people who were hospitalized with salmonellosis after kissing bearded dragons, and other reptiles.
Reptile-associated salmonellosis is a major concern, and while there are ways to make reptile ownership very safe for most people, some risk will always remain. Certain behaviours will increase that risk. A large percentage of healthy reptiles have Salmonella in their intestinal tracts, and anything that’s in the intestinal tract ends up in the animal’s habitat and on its skin. Kissing reptiles is an obvious way to be exposed to this bacterium, which can cause serious disease in some situations.
Among the report's recommendations are:
- Families that own a bearded dragon or similar reptiles are advised to consult their doctor if they become ill with symptoms of fever, vomiting, abdominal pain and/or diarrhoea.
- They should also inform their GP that they keep a reptile. Children are particularly at risk because they like to stroke and handle pets.
- NHS Forth Valley have also issued a guide for pet owners to reduce the risk of catching Salmonella from lizards, which includes supervising children to make sure they do not put the animal, or objects it has been in contact with, near their mouths.
- It also recommended washing hands with soap and water immediately after handling a reptile, its cage or any other equipment, keeping a reptile out of rooms where food it prepared or eaten, and disposing of droppings and waste water down a toilet, rather than in a sink or bath.
Just common sense.
More information about reptiles and Salmonella can be found on the Worms & Germs Resources - Pets page.
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 couple months ago, I wrote about a family suing PetsMart over a case of rat bite fever in a child.
Now, a San Diego family is suing PetCo after their ten-year-old son died of the same infection. Rat bite fever is a bacterial infection caused by Streptobacillus moniliformis, and it is almost always associated with bites from rats.
The San Diego family’s situation is tragic. Fortunately fatal zoonotic diseases from pets are rare. But when they happen, who’s to blame?
Part of figuring that out is thinking about what has to happen for an infection to develop, and where that cascade can be interrupted.
What has to happen for rat bite fever to develop?
The rat has to be carrying the bacterium in its mouth.
- The bacterium is found in basically all rats, so you have to assume that every rat is infected. (So, it’s hard to blame the supplier.)
The bacterium has to get into the person's body, usually by a bite.
- Bite avoidance is therefore key, and involves proper handling of the rat and selecting a rat that has a good temperament.
When the bacterium gets into the body, it has to be able to cause disease.
- Most often, the immune system takes care of it. However, the number of bacteria that get into the body, the weakness of the immune system, and the whims of biology all play roles. In an otherwise healthy child, bite first aid is critical to help remove as many bacteria as possible from the wound before they invade the rest of the body.
To me, it all boils down to education.
- Pet stores need to inform purchasers about infectious disease risks and preventive measures.
- People need to take responsibility to learn about any pets they may purchase (before they get them), and take measures to reduce the risk of zoonotic pathogen exposure.
- Physicians need to be more aware of zoonotic diseases and ask about pet ownership and animal contact.
Would any of these have made a difference here? It’s hard to say. However, these are all relatively easy things to do and could probably prevent a lot of infections.
More information about Rat Bite Fever can be found on the Worms & Germs Resources - Pets page.
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.
It's a scary sounding headline: “Cat Bites Pose Risk Of Infection As 1 In 3 Patients Bitten Hospitalized; Teeth Inject Bacteria Into Joints, Tissue” and it cites a research article from the Mayo Clinic in the Journal of Hand Surgery (Babovic et al 2014).
Cat bites are nasty. The mouth of any cat harbours thousands of different bacteria and their needle-like teeth can inoculate bacteria deep into tissues. A variety of complications can occur after cat bites, and they are not something to dismiss as innocuous.
But hospitalization of 1/3 of people that are bitten? Not a chance.
Let’s see what the paper actually said:
The paper is entitled “Cat bite infections of the hand: assessment of morbidity and predictors of severe infection.” It was a review of 193 patients that were presented to one hospital with cat bite injuries to the hand.
- Point 1: The study population is people who went to the hospital for a cat bite, not all people who were bitten.
- Point 2: The study only looked at people bitten on the hand(s). That’s a common site to be bitten by a cat, but it’s also a high-risk site for complications because hands have lots of sensitive and fairly superficial structures (e.g. bones, joints, tendon sheaths, nerves) that are more likely to cause problems if they get infected.
So, it’s pretty clear that 1/3 of all bites don’t result in hospitalization. In reality it's a much smaller percentage, but you really don’t want to be part of that small group, so bite avoidance and proper post-bite first aid are still very important.
Some other highlights from the paper:
- Nineteen percent (19%) of patients were admitted to the hospital at presentation (i.e. they had to stay at least one night). A further 11% failed initial outpatient antibiotic treatment and were subsequently hospitalized.
- Sixty-nine percent (69%) of patients were women (not sure why - could be that more women own cats, more women get bitten by their cats, or more women are likely to seek medical care if they're bitten by a cat, or a number of other reasons).
- Risk factors for hospitalization (compared to people that presented to the hospital for a bite but did not require hospitalization) included smoking, having a compromised immune system and a bit over a tendon sheath or joint. Those are not surprising at all.
- Signs of inflammation (e.g. redness, swelling at the site of the bite) were associated with increased risk of hospitalization. Not too surprising either.
- The average time from bite to presentation was 27 hours. Interestingly, time from the bite to presentation was not a risk factor for complications, as this has been reported as a risk factor previously (and it makes sense that it would be). However, don’t take that as an indication that you can wait a long time to seek medical care after a high-risk bite.
- Complications were those that are typically encountered with cat bites (and good reasons to avoid them): abscesses, tendon infection and nerve involvement.
- Seven percent (7%) of all patients (not just the hospitalized ones) had loss of joint mobility after resolution of infection. Remember that cat bites can have long-term consequences.
- Cultures were only available for some patients, but Pasteurella multocida was the most commonly isolated bacterium. This bacterium is a notorious bite-associated bacterium and is commonly (if not always) found in the mouths of cats.
Crappy headline but an important topic.
Cat bites are bad, and it doesn’t matter if the hospitalization rate is 30% or 0.3%, they can still result in serious problems. They can also be largely avoided through proper cat handling, understanding some basic cat behaviour and proper first aid - things every cat owner should know.
More information about cats and about cat bites can be found on the Worms & Germs Resources - Pets page.
Photo credit: Moyogo (click image for source)
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.
Sometimes, people send me links to articles because they think I’d be interested in them. Sometimes, they do it to see what kind of response they can evoke. I’m not sure which one this was:
I was directed by a couple of people to a recent post of PLOS’s blog about snakes in classrooms. (I don’t really know why a scientific journal organization has a blog to which people who aren’t experts in a given field can submit posts. I would have thought a PLOS blog would relate to PLOS papers, but what do I know.)
I’m sure many people would agree with the sentiments in this blog, but (surprise, surprise), I don’t. It’s not that I’m anti-reptile, anti-pet-in-classroom, or think that the writer is clueless. Rather, he seems to be a passionate and well-meaning educator who just doesn’t see the issues with reptiles in classrooms. I’ve seen the issues and have my take on some of his points (in italics) below.
In this post I hope to give other educators a good foundation for keeping snakes in their classroom. A classroom pet is always a good way to teach responsibility. Administrators love any outside-the-box methods of teaching. Let them know students will be using this animal not just to learn science, but to learn important life skills like responsibility and compassion.
- True, but it has to be logical and safe. It also has to be educational. Animals can be used in classrooms for educational purposes, but they can also be distracting. The practice can be questionable from an animal welfare standpoint (especially for nocturnal species). They can be associated with disease. Reptiles are the leaders in that class, and reptile-associated salmonellosis has occurred from classroom snakes and other reptiles. Widespread Salmonella contamination of feeder rodents adds an extra level of concern.
- I also doubt administrators like outside-the-box ideas that pose a health risk to students (and therefore liability).
Your administrator may bring up questions about health risks. Salmonella is often associated with pet reptiles. This can be a bit misleading. Most animals, including pets like hamsters and guinea pigs can carry salmonella, but because turtles are wild caught, and often live in terrariums there is a better chance of salmonella living on their shell.
- No…(multiple no’s actually). While most animals can carry Salmonella, the prevalence of Salmonella shedding by pet mammals is very low. The rate of Salmonella shedding by captive reptiles is, in contrast, very high. Studies looking at snakes over time have shown that virtually all captive snakes are shedding Salmonella.
- It’s not just wild caught turtles that are the issue. Captive turtles are also a big concern (the bigger concern, actually).
Most snakes are kept in the same cage setup as hamsters and have little risk of ever having salmonella on their skin.
- Not a chance. Most do. As mentioned above, studies have shown high (to ubiquitous) carriage of Salmonella by snakes.
I have been handling snakes for 25 years and admittedly have poor hand washing skills and have never had an issue.
- That’s similar to saying “Gee officer, I drive drunk all the time and I’ve never killed anyone, so you have to let me go.” Yeah, that’s an extreme analogy but you hopefully get the point. Reptile contact causes thousands of cases of salmonellosis in people every year. There might be no infections in this classroom over the next ten years - or a child could die next week. It’s more likely that the former will happen, the the latter is possible.
I do keep multiple bottles of hand sanitizer in the classroom and make sure the students properly sanitize after handling and/or cleaning.
- That’s great. It’s an important risk reduction tool, but it’s not perfect and doesn’t compensate for the risk.
I would wager students are more likely to salmonella in the lunch line than they are from snakes in a classroom.
- I doubt it. Even if it was true, eating is a required event. Having a snake in the classroom is not.
Once bitten, the students lose most of their fear and wear it as a badge of honor.
- Multiple issues with this one...
Some issues are often overlooked:
- Do teachers always know if they have any high-risk (immunocompromised) kids in the class?
- Do teachers always know if there will be any high-risk kids visiting the class?
- What if a student is very afraid of snakes? How is that managed? (Is it managed? Might a child be afraid to say anything and instead work in a very stressful situation in silence?)
- Are students eating in the same area as the snake (a high risk activity to be sure)?
Here's my standard disclaimer: I actually like reptiles. Now that our kids are beyond the high-risk ages, Heather would be the main barrier to a request from them for a reptile, not me. However, while I like reptiles, I don’t like them in all situations. When the Salmonella risk can’t be contained and assurances can’t be made that only low-risk people will be exposed, reptiles shouldn’t be kept around. A classroom is a perfect example of just such a situation.
More information about Salmonella and safe management of different pets can be found on the Worms & Germs Resources - Pets page.
A few news articles have reported infection of two cats with the H1N1 flu virus. These are the first feline cases reported in Canada, but similar cases have been reported elsewhere, so it’s reasonable to assume that there have been previous undiagnosed feline cases in Canada. Nevertheless, it’s useful information.
Unfortunately, the new reports are very minimalistic in their details - not quite "cat-flu-dead" but pretty close. Information like what clinical signs the cats had, whether there were infected people in the household first, how infection was diagnosed and how the virus strain was confirmed would be useful.
Cases like this always raise a few questions:
What’s the risk to people in the household?
- Pretty limited. We don’t know if infected cats are able to spread the H1N1 virus (though we know that cats experimentally infected with the H5N1 flu shed enough virus that they could pose a risk).
- Nonetheless, it’s important to consider the household disease dynamics. From where did the cat get H1N1? From a person. With what people do most cats almost exclusively have contact? People in the household. So, if the cat was infected, it was probably infected by someone in the household or someone who visited the household, both of which pose a greater risk to other people in the household than the cat.
What’s the risk to the cat population?
- Pretty limited for a few reasons. Most cats don’t tend to have contact with that many cats outside of the household, and the flu virus is shed for a short period of time.
- Cats are also not very susceptible to the virus, so an infected cat would have to be shedding appreciable amounts of virus, have an encounter with a susceptible cat during the short time it’s shedding virus, and then this low-likelihood scenario would have to repeat itself in order for the virus to establish itself in the cat population.
Can cats be a source of new flu viruses?
- In the big picture, this is the main concern. Any species that can be a host for a human flu virus and other flu viruses is a concern because of the potential that infection with multiple viruses at the same time could lead to creation of a new virus - one that is still able to infect people, but is different enough that people don’t have any immunity and current vaccines don’t work (which means it could potentially make a lot of people sick very rapidly).
- However, the risk of this scenario is exceedingly low in cats since H1N1 infection in this species is very rare, and infection of cats by other flu viruses is ever more rare. Therefore, the odds of concurrent infection AND reassortment of the viruses AND transmission to a susceptible host that can further spread the virus is are extremely remote.
An outbreak of equine herpesvirus type 1 (EHV-1) neurological disease (also known as equine herpes myeloencephalopathy (EHM)) is underway in a currently undisclosed location in New Zealand. It appears that at least 12 horses have been affected with 6 deaths, all on one farm.
This is being described as the first outbreak of the neurological form of EHV-1 in New Zealand. That's pretty surprising to me, since this virus in endemic in the horse population throughout the world, and although the neurological form of disease is sporadic it's certainly not a rare occurrence. I imagine there have been periodic cases and maybe small clusters, but perhaps they mean that this is the first large outbreak to be identified (but that’s a guess). We do seem to be seeing more large EHV-1 neurological outbreaks in recent years, and I don't think it’s just because we're recognizing them more.
Fortunately, there is now much more willingness amongst most sectors of the equine industry to take these outbreaks seriously and act much more quickly and comprehensively than in the past (when getting people to admit to an outbreak was a challenge, let alone getting any action).
Hopefully this one's been contained on the farm and no further spread will be encountered.
Stay tuned for the launch of WormsAndGermsMap, a real-time disease mapping site to track cases like this. Coming soon.
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!)
Rabies in horses is pretty rare but far from unheard of, and each case should be a reminder of the need for proper vaccination. The latest US case was a horse in Newport, New York, but I haven’t yet been able to track down more details. Presumably, human and animal contacts are being investigated, with assessment being made as to whether there was potential exposure to rabies virus. For people, that would mean a course of post-exposure prophylaxis. For animals, that would mean a quarantine, observation period or euthanasia, depending on the species and vaccination status.
The risk to people is quite low. The biggest human health risk is from being attacked or otherwise physically injured by a neurological horse, as opposed to getting rabies from an infected horse. But rabies is something with which we don’t play around, so anyone deemed to have been exposed will presumably be treated.
Rabies isn’t common in horses but it kills. Vaccinate your horses (and other animals).
Although at times it may seem that winter is never-ending in parts of Canada, spring is actually only a couple of months away. Along with spring comes insect season, and along with insects comes more than a few viruses. One of these is the virus that causes equine infectious anemia (EIA). This pathogen is a retrovirus like the human immunodeficiency virus (HIV), but EIA only affects equids (e.g. horses, donkeys, mules). It's a very serious concern in the horse world, because horses become infected for life, and in Canada we have strict control measures to help prevent the spread of EIA into and within the country. Nonetheless, in 2013 cases were detected on numerous premises in BC, Alberta and Saskatchewan. Maps of the areas affected are available of the website of the Canadian Food Inspection Agency (CFIA).
To help horse owners understand more about this disease, the existing control program and the reasons behind it, as well as how they can help prevent the spread of EIA, we've created two new info sheets in collaboration with Equine Guelph and Equine Canada: a full-length version complete with references (9 pages) and a shorter summary version (4 pages). Both versions are now freely available for download from the Worms & Germs Resources - Horses page, along with our many other equine infectious disease info sheets.
The first North American case of H5N1 avian influenza ("bird flu") was confirmed in an Alberta resident last night, causing much concern but posing little true risk. The affected person had just returned from a trip to China and began showing signs of illness during the flight from Beijing to Vancouver. After spending a few hours in the Vancouver airport, the person continued on a flight to Edmonton. The person's condition continued to deteriorate after returning home, and the patient was admitted to hospital on January 1, dying two days later.
H5N1 flu is a big deal. This bird-origin virus has only been identified in 648 people, mainly in Asia. However, 384 of those have died. Fortunately, it’s not transmitted very easily to people, and almost all human cases have occurred following close contact with infected poultry.
So, the risk posed by the Alberta case is very low, even to people who shared the long plane ride.
There are some strange aspects of this case though. The affected person didn’t have any known contact with live poultry, which is unusual. It’s even more unusual that the person reportedly only visited Beijing, where no cases of H5N1 have been detected, and did not travel to other areas of China where the virus has been found before.
As reported by the CBC, “China is going to be very interested in this,” said Dr. Gregory Taylor, deputy chief public health officer for Canada.
True. I think Canada should be interested in this too.
A case that’s unusual is a concern. Most often, things that appear to be strange or new don’t end up being anything remarkable. However, a disease that was potentially acquired in an area where it has not been found before, and not necessarily from the known main source means that you have to think about other sources (including humans). If this came from another source, maybe there is more risk. It’s very unlikely though, and chances are it will be eventually be explained (e.g. perhaps the person was in a restaurant that kept live poultry on hand which came from an area where the virus has been present).
I assume this H5N1 virus will be sequenced in the next day or so to see how it compares with other known H5N1 viruses. That will answer some questions.
Despite its high mortality rate, the H5N1 virus isn’t really the major concern here, because it’s rare and poorly transmissible between people. The concerning situation is if H5N1 gets together with human seasonal flu and ends up becoming a virus that is both highly transmissible between people (like seasonal flu) and highly fatal (like H5N1). The odds of this are limited, but the pandemic potential of a new virus of this kind is why there’s a lot of flu surveillance.
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.
A Colorado family is suing PetsMart and a rat supplier after their son developed rat bite fever (RBF), following a bite from a newly acquired rat. Lawsuits seem to be increasingly common after zoonotic infections, which is probably more of a reflection of an increasing tendency for people to sue, not an increasing occurrence of zoonotic diseases. However, questions of liability, and the responsibility of both the purchaser and the seller are interesting to consider. Here are some statements in a report about the lawsuit, with my comments:
They claim the pet store had ample evidence that the rat was sick, but sold it anyway.
- Firstly, it wasn’t sick from Streptobacillus moniliformis, the bacterium that causes RBF. I don’t doubt that the rat was sick but that really doesn’t have anything to do with the risk of RBF.
- Secondly, if it was so obvious, why did they buy the rat? Buyers have a responsibility to learn about pets they are considering buying, to pay attention to animals they are purchasing and take measures to protect themselves. If they put even a minimal amount of effort into researching pet rats, they would have hopefully learned about RBF, things to consider when selecting a rat, and how to manage bites.
"The rat originally sold to [the father] Robert and Steiner was ill and died," the complaint states. "This rat became aggressive and at the same time sneezed a lot as if it was ill. Robert was then given a substitute rat which was also ill and infected with rat bite fever. It displayed the same behavior as the first rat about one week after it was given as a substitute for the first rat.”
- Same issues as above. It wasn’t sick from the bacterium that causes RBF. I doubt they actually confirmed that the rat was carrying the bacterium (as is suggested here) but it presumably was, since that bacterium is found in pretty much every rat.
- Also, if they bought a sick and aggressive rat, did they really think a rat from the same store at around the same time would be any different?
The family claims the rats "were not inoculated carefully," but were subjected to a shoddy batch immunization.
- I wonder what they were actually "inoculated" against. There are no standard vaccines for rats, and no vaccine against RBF exists.
Rainbow, upon information and belief, is known by members of the public including P.E.T.A. [People for the Ethical Treatment of Animals] to negligently and carelessly maintain the animals it sells to PetsMart and this fact is known to PetsMart at all times relevant including before the sale of the rat."
- That wouldn’t surprise me. Mass producers of pets, be it rodent warehouses or puppy mills, aren’t known for their quality of care. However, that’s a separate issue. It needs to be addressed more broadly but isn’t related to the risk of RBF in this case.
This isn’t meant to blame the victim. It’s unfortunate that the child got RBF. Pet stores and suppliers need to do a much better job of providing only healthy animals. However, at the same time, there’s no way to completely eliminate the risk of disease transmission and people have to learn what to do to reduce the risk, and then actually use those basic, common sense practices. There are certainly situations in which pet stores are negligent, but it’s hard to argue that this is the case here, when they’re dealing with an infection from a bacterium that is present in all rats.
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.
Here's another one of my favourites from the archive (largely because it didn't happen to me) that was worth re-posting (original post date 11-Oct-2009).
I was talking with a colleague the other day and somehow norovirus came up. He explained how once, his wife had viral gastroenteritis and ended up vomiting on their cat. Weirdly enough, his wife told my wife the same story (they work together). My wife got a better version of the story which included a nice image of her chasing the cat around the house in her sickened state because the cat was splattering vomit all over the place. (Yuck!)
Anyway, beyond being an entertaining story (as long as it's not you doing the puking and chasing), it raises the question: if you've turned your cat into a biohazardous (and stinky) norovirus vector, what do you do to clean it up?
Dogs and cats cannot become infected with norovirus. However, they could potentially act as a source of infection for people if their coats are contaminated with the pathogen. Usually, I think about this in the context of someone having a little contamination of their hands and subsequently touching a pet (not a vomit-soaked animal, although evidently that can happen too).
So, what should you do? I don't really know. The CDC recommends using bleach or another approved disinfectant on contaminated surfaces, but that's obviously not an option for a cat. Heating contaminated objects to 60C is another recommendation, but again, not for a live animal.
I guess giving the cat a bath would be a good start, and it would presumably greatly reduce the amount of norovirus on the coat. However, if you have viral gastroenteritis already you're probably not in much of a state to do that. Another family member that is not flat-out sick in bed could do the job. However, anyone bathing a heavily contaminated animal should wear a mask and gloves, change their clothes after, clean any surface that gets contaminated in the process with bleach or another disinfectant, and (of course) wash their hands. Unfortunately, I suspect if you had to bath a cat covered in norovirus that you would probably end up getting infected, either from the cat or the contaminated environment. Leaving the animal covered in vomit is not a good alternative either, since it would continue to contaminate the household as well as look and smell really bad. We don't know how long norovirus can survive on an animal's coat, but it's reasonable to suspect that it could survive a couple of days. Keeping the pet away from uninfected individuals for a week or so wouldn't be a bad idea.
The easiest way to handle this is to avoid vomiting on your pets.
From the archives...Why should I vaccinate Fluffy, he's an indoor cat? (aka Why I'm glad I vaccinated Finnegan, my indoor cat)
Over the past few years, I've written a lot of posts on this blog. Hopefully the odd one's been interesting and/or informative, and in the spirit of recycling (not laziness!) I'm going to re-post some that I thought were memorable or of particular interest.
The first one is actually the second post ever on this site (original post date: April 11, 2008).
Picture this. I’m driving home from the airport and get a call from my wife who’s locked in the bedroom with our kids because a bat is flying around the house. It’s not necessarily a big deal, except for the fact I thought I might have seen a bat in the house a couple days earlier, and a bat in a house with access to sleeping people = rabies exposure! [2013 addition: Not all jurisdictions consider this to be exposure now.]
I’ll save you the long but somewhat funny saga, and just say I eventually caught the bat. Our sigh of relief was short-lived, however, because it came back rabies positive. That meant we all needed rabies post-exposure prophylaxis (2 shots for Heather and I who have been vaccinated, but 6 shots for each of the kids). We also have a dog and cat, and they had to be considered exposed as well (the cat almost caught the bat). The cat, Finnegan, is an indoor cat but was vaccinated. The repercussions on the animals were much less than on us. However, if they had not been vaccinated, we would have had a problem.
Protocols for rabies exposure in non-vaccinated animals vary between jurisdictions, but long quarantines are the norm, and euthanasia often is chosen.
The take home message is if you care about yourself, your family and your pets, vaccinate your pets against rabies - even with indoor-only animals. In most places it’s the law. It’s also good sense.
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 rabies exposure incident in New Jersey provides another example of some common good and bad points that come up in these situations.
Fifteen people from four families, along with a veterinarian, are receiving post-exposure treatment after contact with a rabid kitten. In the all-too-familiar scenario, a kitten was found in a cat colony outside a workplace and taken home by a well-intentioned individual. A couple of weeks later, the kitten became sick, ultimately showing signs of neurological disease. It was euthanized at a local veterinary clinic, and subsequently identified as rabid.
A sibling of the rabid kitten that was adopted by a different family is under a strict six month quarantine. As opposed to most rabies exposure quarantines, the odds of this kitten being infected are reasonable high, so the little critter is certainly a concern.
The good points:
The kitten was taken to a vet.
- This may sound simplistic but it’s critical. If the kitten had died before being taken to the clinic, would testing have been performed? It’s hard to say but it’s much less likely. While people don’t tend to think about diagnostic testing after their pet has died, it’s important to consider what might have killed the animal and whether there are any risks to people that need to be evaluated.
Rabies testing was performed.
- Again, maybe this seems straightforward but this is a critical step. The veterinarian has to identify the potential for rabies (pretty easy here) and explain the need for testing to the owner (or alternatively, get public health personnel involved to seize the carcass and mandate testing… a much messier approach).
The bad points:
Lots of people were exposed to the rabid kitten - a total of 15 people from four families.
- That’s hard to prevent, in reality. Kittens attract attention. Whether all 15 individuals actually had contact worthy of calling them exposed to the virus itself isn’t clear. There’s no mention of anyone being bitten. However, given the sharp teeth and playful behaviour that can easily result in little bites (or saliva-contaminated scratches), it is much better to err on the side of calling someone exposed.
All 15 people went to an emergency room for treatment on a weekend.
- That’s a waste of resources and ER time. Rabies exposure is a medical urgency, but not an emergency. Rarely do you need to get treatment started immediately, especially if it wasn’t a large bite to the head or neck. They could have waited until regular hours and gone to their physician or public health. Often, there’s poor communication and lack of understanding regarding the time frame for post-exposure treatment, which can lead to this.
The veterinarian was exposed.
- That may have been unavoidable. However, a young, unvaccinated kitten adopted from a feral colony that has neurological disease is rabid until proven otherwise. Basic infection control practices can reduce the risk of rabies exposure. Maybe those were used and exposure still occurred; that’s possible, but it’s a reminder that prompt identification of rabies suspects and using good infection control practices is important.
These days, there’s more and more doom-and-gloom information about multidrug-resistant bacteria. They’re in our hospitals, medical tourists, people on the street, our pets, our food, and pretty much anywhere else you can think of. We can now add crow poop to the list too.
It’s almost to be expected, really. We know that birds can carry various resistant bacteria, and the more contact birds have with human environments and food animal environments, the greater the chance these bacteria are going to be transmitted between them (in one direction or another). It's important to remember that resistant bacteria are also present in nature, independent of human activities.
A recent report of a pretty high profile multidrug-resistant bacterium - vancomycin-resistant Enterococcus (VRE) - in birds wasn’t all that surprising. The study (Oravcova et al, Environmental Microbiology 2013) reported finding enterococci carrying the vanA resistance gene in 2.5% of 590 crows sampled in multiple US states. It was quite interesting though, because VRE is (in North America) a human-associated bacterium. It’s a little more muddled in Europe where VRE was an issue in food animals, in part due to former use of a drug related to vancomycin (avoparacin) in some food animal species. Here though, we rarely see VRE in anything species but humans. This raises some interesting questions about where these crows picked up VRE, if they are able to carry the bacterium for long periods of time, and if they can act as a source of human or animal infection.
Does this bother me? No. It’s of academic interest, but not something that’s going to pose a real risk to me. I tend not to walk under trees full of crows with my mouth open, and I’m pretty sure I’d wash my hands if a crow pooped on them. Yes, there’s the chance that I could have unnoticed contact with contaminated crow poop remnants on an outdoor surface, but the odds of it containing viable VRE are pretty low, and there are lots of other things that I’m more likely to pick up in my daily activities. In terms of VRE, I’m presumably more likely to be exposed in other ways than from crows. However, the study is still important in that it shows how widespread antimicrobial resistance is, how complex the issue is and how we need to do more to understand the ecology and epidemiology of various resistant bugs.
There's no need to go exterminating crows, but Johnny Depp may want to consider an alternative style of hat.
Pet aquatic turtles have been implicated in three outbreaks of salmonellosis involving 43 US states over the past year and a half. Disappointing, but not surprising.
Disappointing, obviously, because people are getting sick. Disappointing also because these outbreaks have occurred over and over, despite availability of good information on how to reduce the risks.
It’s not surprising, though, because it’s happened so often.
Why? It’s a combination of people not researching these animals properly before buying them, pet stores not providing information, turtle farmers in denial that there is a problem, people flouting the small turtle ban, and poor overall awareness (and application) of basic infection control measures (more on that in a minute).
The Michigan Department of Community Health (MDCH) has reported that 5 people from Michigan have become ill as part of these outbreaks. As is typical, most were kids.
So, if you own a pet turtle, what do you do?
“We don’t recommend that they release them into the wild. Instead, we recommend that you contact a pet retailer, a pet store, to talk to them about it. Also, you can speak with a local animal shelter or a veterinarian for other options as well.” said MDCH spokesperson Angela Minicuci.
That’s not bad advice. However, the pet store and vet probably aren’t going to take the turtle. The humane society might (and those that do might try to find it a home or might just euthanize it right away). There’s another step here that’s forgotten: doing a risk assessment.
Are there high-risk people in the household (kids less than five years of age, elderly, pregnant women, people with compromised immune systems)?
- If yes, the turtle should be re-homed.
- If no…
Are you willing to accept some degree of risk, risk that can be mitigated with some basic practices?
- If no, the turtle needs a new home. (There’s always some degree of risk with turtle (and any animal) ownership).
- If yes…
Are you willing/able to take some basic measures to reduce the risk of Salmonella exposure, on the assumption that your turtle is Salmonella positive?
- If no… (take a guess here) the turtle needs a new home.
- If yes...
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).
In my line of work, I deal with feces from a lot of different species. Never once, however, have I thought to model defecation pressure and distances.
Maybe I’m just strange.
A few years ago, German researchers felt the need to model the defecation habits of penguins. The title of the paper, published in Polar Biology, was “Pressures produced when penguins pooh - calculations on avian defaecation" (Meyer-Rochow et al 2003).
The authors considered the fact that penguins don’t leave their nests to defecate (probably preferring not to freeze every time they need to poop). Rather, they observed that penguins move to the edge, “stand up, turn their back nest-outward, bend forward, lift their tail, and shoot. The expelled material hits the ground maximally 40±12 cm away from the bird and then leaves behind a whitish or pinkish streak that can end a few centimetres from the nest’s periphery and may be up to 1 cm wide.”
That observation lead (perhaps fostered by some alcohol?) to questions about the exit velocity of the feces.
Given their protected status, you can’t run around poking and prodding penguins, so much of the research is done from a distance. The researchers in this case used pictures to estimate the "aperture" and determined it to have a "maximal diameter of 8 mm at the moment of "firing"."
Using the size of the "exit" and an estimate of average penguin poop viscosity, along with the angle and distance of firing, they used mathematical models to determine the "penguin-generated pressures" associated with defecation.
I won’t get into all the of the calculations. Suffice it to say, the image at right will probably not been seen in too many other scientific papers.
They concluded that "fully grown chinstrap and Adelie penguins generate pressures between 10 kPa (77 mmHg) and 60 kPa (450 mmHg) during the evacuation of their faeces on land. The process of defaecation commences with the highest pressure initially and then rapidly drops to zero, hence the production of faecal streaks (and not ‘‘blobs’’). In water, different parameters would apply, although (as in air) the smaller the cloacal diameter, the higher the pressure."
And to wrap it up…
"All birds, penguins included, spend a considerable time preening and cleaning their feathers. It seems therefore that these birds propel their faeces as far away as possible (with a minimum amount of effort) lest they soil their plumage. Birds could theoretically increase their projectile defaecation range by squirting 45° up-wards. However, their upright posture and position of the vent prohibit this in penguins, but in eagles and other birds-of-prey the squirt is, indeed, directed upward by ca. 15–30° (unpublished observation). The forces involved apparently do not lead to an energetically wasteful turbulent flow. It is interesting to note that the streaks of the faecal material radiate from the edge of the nest into all directions (no preference is noticeable). Whether the bird deliberately chooses the direction into which it decides to expel its faeces or whether this depends on the direction from which the wind blows at the time of evacuation are questions that need to be addressed on another expedition to Antarctica."
Photo: Adelie penguins, Antarctica (credit: JHB Anderson)
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.
A local county newspaper had a front page headline about a zoning amendment that was approved to allow for a feeder rodent facility that will produce about 10 000 rodents a week (I know, apparently there aren't a lot of big things happen around here). Co-incidentally, a couple days later, I received an alert and fact sheet from the Ontario Ministry of Health and Longterm Care and the Office of the Chief Veterinarian of Ontario about Salmonella and feeder rodents because of an increase in human Salmonella Typhimurium infections in people in Ontario and a link to feeder rodents in some cases.
It’s not really a surprise. Large and sustained outbreaks of salmonellosis associated with feeder rodents have been reported for a while. These rodents are often produced at large facilities with hundreds of thousands of rodents, and if Salmonella gets in the facility, thousands (or millions) of biohazardous small-and-fuzzy snake snacks can get shipped around the world.
The fact sheet is attached here, and it contains good information about the standard reptile and rodent handling practices that I always keep coming back too: wash your hands, keep high risk people away, prevent cross-contamination of snake food with people food (e.g. don’t thaw frozen rodents in an open container in the fridge (yuck… but it happens) or cross contaminate kitchen surfaces) and other basic hygiene practices.
Infection control isn’t complicated, it’s often just ignored.
Cat hoarding has been in the news in the Toronto area a few times lately. Multiple incidents of serious cat hoarding have been identified in the past month, involving large numbers of cats being kept in horrible conditions. It’s not hard to see how cat hoarding can create infectious disease challenges. I can’t see how anyone could keep a large number of cats in a house without problems, even if they worked very hard to keep things under control. Add together the issues of keeping massive numbers of cats in a confined space, no veterinary care, poor nutrition and limited hygiene, and you can see how the cats and the building would quickly become biohazardous. Add in mental health issues and hoarding of other objects (both or which are also common in such situations), and you get a house that’s a cesspool, fire hazard and no place for humane housing of any animal or person.
When cat hoarders are investigated, there are often dead cats found in or around the house. There are also often cats that end up being euthanized promptly because of severe disease. A wide range of diseases can be encountered in such cat-dense and hygiene-deficient situations. Mostly, the typical feline diseases are found, including vaccine-preventable illness and a whole range of opportunistic bacterial infections. However, these cats can be very compromised and therefore prone to rare infections as well. A recent report describes one of these unusual infections. The report (Brooks et al, Veterinary Microbiology 2013) describes extraintestinal pathogenic E. coli (ExPEC) infection in one of about 60 cats from a hoarding situation. The cat died and the bacterium was found to be the cause of pneumonia and kidney abscesses.
Is this a major concern for feline health? Not really. This is presumably a rare infection that occurred in a highly compromised cat, and not the crux of a new problem. However, it shows the wide range of diseases that can occur and, probably most importantly, that some of these infections are zoonotic: ExPEC is actually a significant human health concern, since it can cause similarly severe disease in people. It’s been previously shown that people and pets can share the same strains of ExPEC within households, and pets have been suggested as being a potential source of some human E. coli urinary tract infections (another form of ExPEC infection).
In the hoarding situation with the ExPEC-infected cat, there was concern not only for people who had contact with the cat, but a wide range of emergency responders, public health personnel and probably many other people who entered the house (since one cat with disease probably means many cats shedding the bacterium in their feces, which means lots of contamination in the hoarder’s house).
Dealing with hoarding is a complex problem because of typically weak laws, reluctance to enforce laws, mental health issues and a range of other challenges. Early identification of hoarders with proactive intervention - before the place becomes a disaster - is important, but easier said than done.
Australian Elmer Fudds beware… there are concerns that feral pig hunting is a risk factor for brucellosis in New South Wales. Brucellosis is a rare disease, but a report like this raises concern because it can be nasty, and it can also be hard to diagnose (or it's not considered right away).
We don’t have feral pigs in Ontario, but they are common in many areas, including parts of the US. In Australia, it’s been estimated that there are over 13 million feral pigs ranging over approximately 38% of the country. Any contact with animals carries some degree of infectious disease risk, and hunting is no exception. In fact, some risks are higher because of the close contact with the target animal and its bodily fluids after its been killed.
The brucellosis story is a bit old, and relates to a NSW Public Health Bulletin from a few years ago (Irwin et al. 2009) of four cases of this bacterial infection detected between December 2006 and September 2009. The infected individuals, all men, reported having hunted feral pigs before the onset of disease, and they all butchered the pigs without any protective gear (e.g. gloves). They didn’t have any of the common risk factors for brucellosis, such as overseas travel or consumption of unpasteurized milk from areas where the disease is endemic in dairy animals, so it was likely that the pigs were the source. Public health authorities trapped and tested 200 pigs, all of which were negative. However, 200 negative pigs from a multimillion population certainly doesn’t mean the pigs are Brucella- free, as was shown when Brucella suis was found in testicular samples of pigs from southern Queensland in a separate investigation.
All of the men reported typical symptoms including fever, sweating, abdominal pain, vomiting, back pain and "loin" pain (a term that’s not typically used since it’s not very descriptive - brucellosis often causes testicular swelling so maybe that’s what it means. Either way, it doesn’t sound pleasant).
Brucellosis is a disease that warrants some attention because it can be nasty and it can take a while to diagnose. Fortunately, it’s rare in most developed countries, although the same link between brucellosis cases and hunting feral swine has been seen in the US as well. Hunters need to be aware of a wide range of potential zoonotic diseases. Additionally, brucellosis is a concern for pet owners since sporadic human cases associated with transmission from pets have been reported, and this may be an emerging or previously overlooked problem.
It doesn’t. (Just like monkeypox doesn’t come from monkeys.)
Cowpox is a viral infection and the natural reservoirs are actually rodents. Humans, cats and cows are amongst the more common "accidental hosts" - species that get infected sporadically but are not reservoirs. Contact with an infected rodent can result in transmission of cowpox to people. The virus can also come from an animal that gets cowpox from a rodent and then passes it on to a person, as a Dutch teenager found out...
A 17-year-old girl found a kitten in the ditch and picked it up. It was sick and ultimately died (probably not from cowpox). She later developed a skin lesion on her wrist, which progressed to red lumps over her arm. Not surprisingly, cowpox didn’t jump to mind when she saw her doctor, so it took a while before a diagnosis was made, but they figured it out eventually. Since cowpox infection is usually self-limiting in individuals with a normal immune system, the girl eventually got better without any specific treatment. It took a couple months, though, and left a scar.
Presumably the girl got cowpox from the kitten, which probably got cowpox from contact with an infected rodent. This is an unusual series of events, certainly, but far from unprecedented. Cats are one of the main non-reservoir species that are implicated in cowpox transmission to people, presumably because they get infected while hunting wildlife (e.g. rodents). Cowpox is a pretty rare infection in people and usually not very severe, so it’s nothing to be paranoid about, but it’s another reason to use good hygiene practices and keep cats from going outside and hunting.
FYI Cowpox got its name because infected cows often develop lesions on their udders, and it was a common infection of dairymaids in times when cows were milked by hand. This virus also features prominently in the development of the world's first vaccine in the late 1700s, as the cowpox virus itself was used as a vaccine against the deadly smallpox virus.
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 had an interesting question today about the cat-associated parasite Toxoplasma gondii. It can cause serious infection in people that ingest it, particularly in immunocompromised individuals and pregnant women, but disease is rare. Since cats can pass one form of the parasite in their feces, the question was whether using flushable kitty litter is a bad idea, since it would result in Toxoplasma being discharged into the sewage system.
On one hand…
- Water is a source of Toxoplasma exposure.
- Food contaminated by Toxoplasma-contaminated water is a also a source of exposure.
- Municipal water was determined to be a possible source of exposure in at least one Toxoplasma outbreak (Bowie et al. 1997).
- The form of Toxoplasma in cat feces is hard to kill, so it could survive routine water treatment measures.
On the other hand….
- Cats rarely shed Toxoplasma. They typically do so only for a short period of time after their first exposure (usually when they're quite young), so the vast, vast majority of household cats are not shedding the parasite.
- There’s a massive dilutional effect when something goes down the drain. To constitute a risk, the parasite would have to come out of the cat, survive waste water treatment and be discharged into the environment, then either make it into a drinking water source (with more dilution and more treatment) or reach someone’s mouth through other routes such as on food or from contaminating the general environment (e.g. soil, recreational water bodies). Even if some Toxoplasma were present in cat feces in flushable litter, the odds that someone susceptible would encounter enough Toxoplasma from this source to cause disease is exceedingly remote.
I don’t think using flushable litter constitutes a public health risk.
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.
I've had the occasional debate with people about the public health risks of rabies in horses.
On one hand...
- Rabies is rare in horses.
- I've never seen a report of rabies transmission from a horse to a person.
On the other hand...
- Rabid horses have attacked (and killed people).
- It doesn't matter whether the horse gave you rabies or stomped on you. Dead is dead.
A Carroll County, Georgia horse owner learned the risk of rabid horses the hard way, but fortunately doesn't appear to have been seriously injured. .
One day, the owner was bitten while getting the horse out of the pasture.
The next day, the horse attacked him....and according to the owner, tried to kill him. That night, the horse was in the pasture chewing on its leg and periodically nosing the electric fence.
While rabies is rare, these are some of the hallmarks...aggression and strange behavior. The horse was euthanized and tested positive for rabies. Presumably, the owner is undergoing rabies post-exposure prophylaxis.
Rabies is nothing to play around with. It's very rare in horses but endemic in wildlife so there's always a chance for exposure in most regions. Rabies vaccination is a cheap and highly effective way to reduce the risk.
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.
'Tis the season...
Eastern equine encephalitis (EEE) is a very serious disease that's fortunately rare in Ontario, but when it happens, it's bad news. It's a viral disease transmitted by mosquitoes (similar to West Nile virus), and we often see a couple of horses affected every year, usually starting around now (late August) and extending into the fall.
The Ontario Ministry of Agriculture and Food has issued an alert after diagnosis of EEE in a 11 year old horse in Simcoe county (other cases have been reported in this area in previous years as well). They say the horse is recovering, which is a bit of a surprise because mortality rates with EEE are very high, and most affected horses die quickly.
What does this mean for horses in Ontario?
Not a lot, since we know EEE crops up every fall, and there's always some degree of risk, but it's a good reminder that this disease is a concern particularly at this time of year. The risk here isn't anywhere near the level it is in some US states, and with only a handful of cases every year (4 last year), the disease's overall impact in Ontario is low. However, infection is typically fatal and therefore not something to be ignored. A vaccine against EEE is available for horses, and it's been debated whether it should be a core vaccine for horses in Ontario. On one hand, the disease is typically deadly. On the other hand, it affects between 0 and a few horses every year, which is not many in the grand scheme of things (but if it's your horse, you don't really care about the "grand scheme" at that point).
What does it mean for people in Ontario?
Despite the name, EEE can affect people too. It's rare, but like in horses, it's devastating. There has never been a confirmed human case in the province, but they do happen Earlier this month an elderly woman in Norfolk County, Massachusetts was diagnosed with and died from EEE (like Ontario, Massachusetts typically sees a few cases in horses every year as well). Humans and horses get infected the same way (a bite from an infected mosquito), so cases in horses mean there is EEE in mosquitoes in the area. There's no vaccine for people, so we're left with mosquito avoidance.
This is one of those "pay attention but don't panic" diseases.
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.
As fall fair season starts, concerns about petting zoo outbreaks rise. While deficiencies are still common, petting zoos seem to be getting better with their infection control measures. People too are starting to get better at doing what their asked to do - namely washing their hands after visiting these exhibits. However, as we’ve shown through a few different studies, compliance with handwashing after being in a petting zoo is far from perfect. People also often fail to recognize the need to wash hands after being in a petting zoo even if they don’t touch an animal. It’s not uncommon to see a family come out of a petting zoo and the parents direct the kids to wash their hands, while the parents themselves just stand back and watch. Yes, if you touch the animals you’re more likely to have contaminated your hands. However, it’s been shown in a few studies and outbreaks that just being in the petting zoo area is a potential risk, and that disease-causing bacteria can be spread to a variety of hand contact surfaces. In short, the bugs aren't just on the animals.
A recent study in Zoonoses and Public Health (Pabilonia et al 2013) provides more evidence. Researchers visited poultry exhibits at agricultural fairs in Colorado and collected samples from areas like cages, feed, floors and tables, i.e. areas where there was direct contact with birds and areas that visitors might touch. They were able to grow Salmonella from 10 of 11 fairs that they visited. Overall, greater than 50% of surfaces that they tested were contaminated with Salmonella. It wasn’t surprising that finding Salmonella was fairly easy, but that number is pretty high.
Does this mean that poultry exhibits should be banned? No. But it indicates that there is some risk, presumably with any poultry exhibit anywhere.
How can you reduce the risk?
- Don’t eat or drink in poultry exhibit areas.
- Wash your hands after leaving (even if you don’t touch anything).
- Don’t take in items that might go into a child's (or anyone's) mouth (e.g. sippy cups, pacifiers).
Particular care must be taken with kids less than five years of age, elderly individuals and people with compromised immune systems. That could mean staying out of the exhibit altogether, or just being extra diligent about the basic measures listed above - it really depends on the scenario, the ability to follow these practices, and the level of risk aversion.
What should fairs do?
- Take measures to reduce environmental contamination, such as housing birds in such a way that bedding doesn’t get spread everywhere.
- Regularly clean environmental hand contact surfaces (e.g. railings, arms on seating/benches).
- Provide signs to make sure that people know what to do (e.g. wash their hands, don't eat and drink).
- Supervise exhibits.
- Provide good hand hygiene facilities.
These measures aren’t too hard to implement and they’re much better than dealing with an outbreak.
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.
This isn't a zoonotic disease issue, but certainly relates to ongoing discussions about keeping exotic pets.
A python from an exotic animal store in New Brunswick apparently escaped its enclosure and found its way into an apartment above the store. There, the python killed two boys, 5 and 7 years of age, possibly while they were sleeping. The snake is in the possession of the police. This is bound to provide more fuel to the fire of recent discussions pertaining to exotic pet ownership, unfortunately from a much more tragic incident that the comical (and somewhat annoying) ongoing saga of Darwin the monkey.
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.
Hastings Racecourse cancelled racing last Saturday because of an outbreak of equine influenza in horses at the track. A recent CBC news report indicates that things started a week and a half earlier, with 150 horses affected when the race cancellations were announced. That's a pretty impressive outbreak.
There's no information about the response, beyond cancelling racing. In some ways, flu is quite easy to control because animals do not become long-term carriers of the virus and infected horses only shed the virus for a short period of time. This makes it easier to contain an outbreak with good infection control precautions, since you only need to implement them over a fairly short period of time. However, the downside is flu is highly infectious and can spread easily and quickly.
I have no first hand knowledge of this outbreak so I can't say anything about what was done or what was missed. However, from a generic standpoint, these are the main problems I see with this kind of outbreak.
There's no response.
- This is too often the problem. This can occur because people don't realize something is happening or the snow-balling of issues that can result. Education is needed to help prevent this.
- Lack of response can also occur because people don't want to tell anyone about an infectious case or don't trust the authorities. This sometimes happens if horsemen are worried about being stigmatized or prevented from racing or showing. Again, education is needed.
- Sometimes, there's mistrust of track or regulatory personnel. If people are worried that the other group doesn't understand or care about their situation, or they don't realize the benefit of communicating, they might try to hide a problem.
There's a late response.
- Another common problem. This usually occurs because people try the "I hope it will go away" approach to infection control first. This rarely works.
- If you get infection control measures in place early, you can contain things much more easily. You're much more likely to contain an outbreak if you only have one horse, or a few horses, affected. It's also easier to contain the disease if you can keep it localized to one barn. Once it spreads to many horses and gets into multiple barns, it can be tough to stop.
- This is why protocols that require reporting of fevers other other basic, early signs of infectious disease (and how to respond to them) should be commonplace.
The response is half-hearted.
- Yet another common problem. Even when people get moving and try to contain an outbreak, it's often not done effectively.
- One reason for this lack of efficacy is people often don't want to do what's recommended. Infection control measures always make life more difficult, and they take time, no doubt. They're important though. Skipping important measures and just trying to do the more convenient ones isn't a good response.
- Another reason for an inffective response is not knowing what to do. Sometimes, I get involved in outbreaks after there's been an initial response and see lots of effort being put into relatively (or completely) useless activities, while the key control measures are ignored. Getting the input of experts as early as possible is critical.
There's inconsistent response.
- This may be similar to 'half-hearted," but by this I mean an outbreak where some people do everything right, and some do little or nothing. Sometimes this is a result of poor communication, and therefore everyone doesn't understand what's happening. Better communication and education can help.
- Other times, this can be caused by simple belligerence: "I don't want to do it so I'm not going to do it!" Sometimes good communication and education can help with this too, by showing people that it's to their own benefit. However, willful neglect is not uncommon and it's hard to handle.
The common themes to preventing these issues are communication and education.
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)
Antibiotic use in animals, and the impact on humans is a controversial area. At a conference a few years ago, one of the organizers posed the question, "What percentage of resistance in human pathogens is attributable to antibiotic use in animals?" They had people write their answers on cards, and later in the day they gave a synopsis of the results. Basically, the responses ranged from 0-96% (or something like that). That's not surprising really, as there are a lot of opinions but there's been a lack of good data. Clearly, use of certain antibiotics in animals in certain situations can lead to increased resistance in some human pathogens. Sorting out the "certains" and "somes" is the problem. It's also clear that there's massive overuse (and abuse) of antibiotics in human medicine that leads to lots of resistance.
The biggest problem is our current lack of data. It's not for lack of trying, but it's an extremely complex area. A study in the upcoming issue of Emerging Infectious Diseases (Collignon et al. 2013) starts to put some more solid numbers behind the concerns. The study took data from a variety of sources and attempted to figure out the number of human deaths from resistant E. coli (just one of the bugs we're concerned about, but a big one) that is attributable to antibiotic use in animals. Their conclusion was that infections with E. coli resistant to 3rd generation cephalosporins (an antibiotic group which is used in some animals and is also important in humans), in which resistance was attributable to antibiotic use in poultry, accounted for 21 deaths and 908 hospital bed-days in the Netherlands in 2007. If this is extrapolated to Europe (which can only be done loosely because of differences in antibiotic use and infection trends between the vastly different EU countries), it would mean 1518 deaths and 67 236 hospital admissions. That's a very small percentage of people in Europe overall, and a small percentage of all the people in Europe who die of resistant infections, but it's still a lot and it's therefor still a concern.
What does this mean more broadly for other countries, other bugs, other drugs? It's hard to say. To quote the authors, "To more accurately estimate the associated increased deaths among persons resulting from third-generation cephalosporin use in poultry, detailed data from more countries is essential." I'd substitute "third-generation cephalosporin use" with "antibiotic use," since we also need to know about other drugs. It's always amazed me how hard it is to get even a basic idea of how much antibiotic use occurs in people and animals, with profoundly different estimates by different groups (often driven by different agendas).
Antibiotic use is a necessity in some situations. We have a moral obligation to keep animals healthy, and healthy animals help make healthy food. However, at the same time, we need to think about standard practices and make sure antibiotics are truly being used wisely in both people and animals. Stopping all antibiotic use isn't practical at this time, nor will it eliminate resistance. Knee-jerk reactions like simply banning antibiotics might actually make some things worse, if they result in other practices that also drive resistance (e.g. adding heavy metals like zinc to animal feed to help prevent diarrhea, resulting in the same pressure for antibiotic resistance, or replacing prophylactic treatment using drugs that are of limited concern in people with later use of therapeutic drugs that are important in humans). However, the use of antibiotics as a replacement for good management practices needs to end, and more thought needs to be given to how to use antibiotics wisely, effectively and sparingly - in all cases (animals and people).
I grew up with cats, and they were all indoor/outdoor. I never really thought about it since that was just the way things were done. Yet, as much as he’d like to convince us otherwise, our current cat Finnegan is an indoor cat. There are a lot of reasons for this.
One reason for keeping Finnegan in the house is zoonotic disease prevention. I was recently giving a talk about "Pets and immunocompromised owners" at the American College of Veterinary Internal Medicine forum, and a recurring theme for reducing the risks associated with cats was keeping them inside. (Want to reduce the risk of the cat being exposed to Toxoplasma? Keep it inside. Want to reduce the risk of Salmonella exposure? Keep the cat inside...).
Another important reason is the animal's own health:
- Cat vs car rarely ends well for the cat, and untold thousands of cats meet their ends on roads every year.
- Cat vs cat isn’t as bad but can lead to cat bite abscesses and transmission of a few different pathogens such as feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV).
- When outside, cats can also be exposed to various insect borne pathogens that can be of concern. This kind of risk varies between regions, with areas such as those where there are ticks carrying Cytauxzoon felis (a parasite normally carried by bobcats) perhaps being the biggest concern.
Wildlife is another concern, in two ways. Just like with cars, cat vs larger critter such as a coyote rarely ends well for the cat. From an ecological standpoint though, greater problems occur from cats killing smaller wildlife. It’s been estimated that free-roaming domestic cats kill billions (yes, Billions) of birds and small mammals every year. I won’t go into all the details here, but there’s a good article on the Canadian Cooperative Wildlife Health Centre’s website healthywildlife.ca about the impact such avid feline predators can have on local ecology.
Some people would argue that cats are better off going outside. Looking back at the cats with which I grew up, a lot died early because they were allowed to go outside. It’s hard for me to justify the risk to the cat, wildlife and public health for some anthropomorphic “he’d really enjoy being outside” argument.
Ok, I had to Google that one…”Moggy” not being a typical Canadian term. Apparently, it’s British slang for "cat." Anyway, the "Death by moggy” article in the UK paper The Sun is pretty basic, mentioning the death of a 59-year-old woman who would probably be considered a classic cat hoarder. She was single and slept with 15 cats in her room, and as described by the coroner “hygiene was not what it could have been due to so many animals.”
I actually don’t buy the "number of animals" excuse. Fifteen cats is a lot, but cats are pretty clean and with some effort, it’s not hard to maintain a hygienic environment. It’s a lot of litter to clean, but it can be done. If there were hygiene issues, it probably went beyond a problem of sheer cat numbers.
Regardless, the report is pretty brief but it appears that the woman died of sepsis (overwhelming bloodstream infection) that was somehow linked to the cats. There’s no mention of whether the cats were actually the source, or if it was a matter of "lots of cats…big mess…must be from the cats." However, the woman was apparently often scratched, so it makes sense that the cats could have been the source of infection or a scratch could have allowed a bacterium from the woman’s skin to cause an infection that ultimately killed her.
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.
An outbreak of equine herpesvirus type 1 (EHV-1) has resulted in implementation of a quarantine at Woodbine, a major Thoroughbred track in Toronto. This outbreak is unrelated to the recent outbreak at an Ontario Standardbred training facility.
The Ontario Racing Commission has issued the following release:
The Ontario Racing Commission (ORC) announced that there have been five confirmed reports of the neurotrophic form of EHV-1 in thoroughbreds residing in Barn 1 at Woodbine Racetrack. One horse was euthanized on June 10 after becoming recumbent with a fever. A second horse in the same barn (Barn 1) also had a fever and showed neurological signs. The second horse was transported to the Ontario Veterinary College for further evaluation and treatment.
Thoroughbred racing will continue at Woodbine. However, due to the infectious nature of this disease, the ORC has ordered the implementation of various infectious disease protocols to protect our equine athletes.
In order to determine any further spread of the disease to horses in other barns, no horses are to exit Woodbine Racetrack without ORC approval for the next 7 days (June 19). This restriction may be reviewed based on the progression of the disease.
In addition, no horse is allowed in or out of Barn 1 or Barn 3 for the next 7 days, including training. This restriction may be reviewed, based on the progression of the disease.
All horses stabled at Woodbine must have their temperatures taken and recorded visibly on the horse’s stall door for inspection. Trainers with horses that have clinical signs consistent with EHV-1 infection (including fever (101.5 F/38.5 C or above), respiratory signs (cough, nasal discharge and/or neurological signs) must report these findings to their veterinarian immediately.
Horse people who had horses at Woodbine Racetrack within the last 7 days should monitor their horses for any signs of illness. Standardbred horses are not stabled at Woodbine Racetrack. As well, the standardbred racing meet concluded at Woodbine on May 20, 2013 and moved to Mohawk Raceway on May 23. Therefore the June 15 North American Cup at Mohawk will not be impacted by these measures.
As with most outbreaks, the next few days are critical to see how far the virus has spread. Early on, you never know whether it's confined to a specific barn or group, or whether it's widely disseminated across the facility. An outbreak that just affects one barn is still a problem, but it's much easier to contain than one that's already moved beyond the initial group. Without knowing how the first horse was infected (something that's rarely identifiable), time and testing are needed to determine the extent of the spread and how hard it will be to contain it.
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.
The latest edition of the University of Guelph Animal Health Laboratory's newsletter contains an interesting report about 4 horses that died over the past few years from what was suspected to be contaminated intravenous fluid solutions. These cases were dead horses that were submitted for post-mortem examination from three different farms, so if anything, this could be an underestimation of the problem.
The first two horses were from the same farm. They were young Thoroughbreds that were routinely treated with intravenous electrolytes, vitamins and minerals (whether by the trainer or veterinarian is unknown). The first horse was found with its head hanging low after treatment. It later developed seizures and died. The second horse showed similar signs. The bacterium Klebsiella pneumoniae was isolated from a few different tissues of the first horse, as well as one of the "jugs" used to administer the fluids. The second horse had the same general lesions as the first, but Klebsiella wasn't isolated; however, this may have been because the body wasn't in great shape by the time it was submitted to the lab, and various other bacteria had overgrown the Klebsiella, making it difficult to isolate.
Another case was a young Standardbred that died after receiving intravenous fluids with vitamins, and a glyceryl guaiacolate jug. It had signs of bloodstream infection (septicemia) and Klebsiella oxytoca was isolated from multiple organs. Various bacteria were isolated from remnants of fluid in treatment bottles.
The final case was a five-year-old Standardbred that died after receiving a home-mixed vitamin jug. It had lesions similar to the other horses and consistent with a bloodstream infection. Klebsiella oxytoca was isolated from multiple organs.
Contamination of multidose drug vials or fluid solutions can occur if bacteria are inoculated into the bottle with a needle when a dose if withdrawn. We've shown this happens with multidose vials in a hospital situation, and of the farm it's even more likely to occur because it's a dirtier environment and, in the case of farm personnel, individuals have less experience with sterile technique. Fluid solutions can be contaminated in the same manner or when something is added to the fluids (e.g. vitamins). Contamination of reused fluid administration sets (i.e. fluid jugs/bags and the IV tubing) is quite likely, and that's why use of sterlie, single-use administration sets is recommended. Adverse events from a little bit of contamination are uncommon, but as shown here, they can happen and they can be severe. There's no information about what contributed to the contamination in these cases, but it's almost certain that poor infection control practices were at the root of the problem. Trying to save money by skimping on sterilization, reusing items without proper care, and using poor hygiene practices in general can end up costing much more.
Darwin's back in the news. He’s a young macaque who is often called the "Ikea Monkey" since he was found wandering around a Toronto Ikea parking lot one day last winter in a designer winter coat. He was seized because of a Toronto bylaw prohibiting monkeys as pets, and transferred to a local primate sanctuary. His owner, Yasmin Nakhuda, has been waging a high profile battle to get him back. There are numerous Facebook pages dedicated to freeing Darwin, and she apparently sent him a birthday greeting (perhaps not realizing it's unlikely that he had internet access at the sanctuary... or can read).
Anyway, Ms. Nakhuda is suing for custody and the trial is currently underway. Needless to say there's a lot of drama in the courtroom as Ms. Nakhuda tries to regain custody of the animal she calls her "son." Much of the trial has centred around issues of property, which I guess makes sense since that’s the main legal avenue.
However, what’s not been mentioned are the greater concerns, namely does Darwin pose a risk to the public and does Ms. Nakhuda pose a risk to Darwin? I think the answer to part 1 is certainly yes, and the answer to part 2 is maybe.
The first question (does Darwin pose a risk to the public) is easy. There are a variety of issues with keeping non-human primates as pets. They can be destructive, they are surprisingly strong for their size, and macaques are notorious for being aggressive, so the risk of trauma alone is a major issue. Disease is another concern, and the big problem in this case is herpes B virus. This virus can be found in most healthy captive macaques and can cause fatal infection in people. The fact that it’s been reported that Darwin was prone to biting makes me cringe, since that’s a huge risk for herpes B transmission. Among the trial testimony was an email Ms. Nakhuda sent to a US primate trainer in November documenting her struggles. Among the problems was aggression that Darwin had towards her son and co-workers.
It’s bad enough that she’s exposing herself and her family (including her human chldren) to Darwin. Exposing people with whom she works (and perhaps people who work for her, and would have a hard time raising any concerns they had) is completely inappropriate, as is taking Darwin out in public (apparently "everywhere," including the gym, grocery store, and obviously Ikea). Ms. Nakhuda either doesn’t understand the issues or doesn’t care. Either way, it’s not good.
I don't doubt that Ms. Nakhuda cares for Darwin. However, as the primate sanctuary lawyer Kevin Toyne said "This is not about who loves Darwin the most." For me, it should be about protecting the best interests of the public and Darwin, neither of which would result in him being returned to his previous owner.
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.
I’ve written about the African dwarf frog and Salmonella issue before, but it’s worth a recap since an overview of the 2008-2011 outbreak was recently published in the journal Pediatrics (Mettee Zarecki et al 2013). The fact that reptiles and amphibians can carry Salmonella is nothing new, nor is the fact that outbreaks of disease can occur in people who have contact with them. However, the scale of outbreaks associated with pets can be impressive.
Here are some highlights from the paper:
- Between January 1, 2008 and December 31, 2011, 376 people were diagnosed with salmonellosis caused by the outbreak strain, a type of Salmonella Typhimurium.
- As is common in pet-associated outbreaks, kids bore the brunt of this one. The mean age of infected individuals was 5 years, and 69% were children under the age of 10.
- Severe disease wasn’t uncommon - 29% of people were hospitalized, half of those being kids less than 5 years of age. Fortunately, no one died.
- During a preliminary study, when they compared people who got sick with a group of healthy controls, they found that people who reported exposure to any aquatic pet were almost 5 times as likely to have salmonellosis. When that was narrowed down to exposure to just frogs, the risk went up to 12.4 times higher than healthy controls.
- When they looked at people who were sick and reported exposure to frogs, only 27% reported having touched a frog, with 46% reporting having fed a frog, 59% having had contact with a frog’s habitat and 60% having had contact with water from a frog’s habitat. Twenty-three percent (23%) reported cleaning the frog’s habitat in the kitchen sink, and 35% in the bathroom sink. This tells us some very important information. It tells us that direct contact with frogs or their environment is a high risk behaviour. However, direct contact isn’t required to get sick. While the frog may stay in its habitat, Salmonella may not. Cleaning habitats in kitchen or bathroom sinks is a high risk activity, because it can result in contamination of common human-touch surfaces and items that go into peoples’ mouths (e.g. toothbrushes, cups).
- Often, disease occurred not long after a new frog was obtained. The median time from purchase of a frog to disease was 30 days (range 5-2310 days).
- Only 17% of people interviewed reported knowing that frogs can carry Salmonella. Over twice as many knew there was a risk from reptiles. This shows there needs to be more education of people who buy animals such as frogs. Pet stores should be required to provide some basic public health information. Pet owners should also take initiative and research potential new pets, including how to care for them and how to reduce the risk of zoonotic infection.
- The outbreak Salmonella strain was found in the environment of some patient homes (not surprisingly), an African dwarf frog vendor (potential source of infection), a large-scale African dwarf frog distributor (a great way to spread an outbreak across the continent) and a daycare centre (that never should have had an amphibian in the first place!).
- One breeding facility in California was the likely source. With centralized, large-scale breeding and warehouse-style distribution of pets (of various species, not just frogs), we’re seeing more large-scale outbreaks like this.
More information about African dwarf frogs can be found on the Worms & Germs Resources - Pets page.
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.
Horse show season is upon us, and with it comes the questions from concerned horse owners who want to protect their animals from the infectious diseases they may encounter at these events. In this case, the specific question is:
What protocol would go into place if a horse with a highly contagious disease such as EHV-1 were to be found at a competition in Canada?
The short answer (to the surprise of many) is that there is no pre-established nation-wide protocol for most equine disease outbreaks. Every outbreak is managed differently, based on the disease, the types of horses, where exposure might have occurred and a range of other factors. Typically, a disease like EHV isn't going to be noted during the show, since it takes some time for illness to develop after exposure. Therefore, the response is more of an investigation of what happened at the show, why and how it can be prevented in the future, and of course trying to prevent further transmission in the community (e.g. identifying exposed horses, communicating with people who have been to the show with recommendations to quarantine and test exposed horses and potentially all horses, surveillance for ongoing transmission from horses that have left the show).
With horses, there's no regulatory body with a mandate to oversee (and fund) this type of investigation unless it's a federally reportable disease like rabies (and even then, assistance may not be forthcoming). Some provinces have more authority and interest (e.g. the Animal Health Act in Ontario gives the province a mandate and powers to intervene) but often investigation is not a priority for regulatory bodies and it's left to whoever is around and interested. There are some good outbreak management guidelines from different institutions or groups (e.g. the ACVIM consensus statements on EHV and strangles) but there is no standard approach. Because testing costs are placed on the owners, responses can be quite variable since getting people to test when indicated can be a challenge. Additionally, getting people to follow quarantine recommendations is a challenge because of inability to effectively quarantine on their farm or unwillingness to do so (usually more the latter). So, each outbreak ends up being managed quite differently.
In general, the key points to outbreak investigation and management are:
- Identification of a problem
- Diagnosis of the problem
- Communication to let people know what's happening
- Identify potentially exposed and infected horses
- Quarantine, if appropriate (usually some form of quarantine is indicated, but not necessarily for all diseases)
- Develop testing recommendations
- Develop and communicate a plan to maximize compliance with quarantine and testing
- Create a way to centralize data collection and communications, so that a clear picture of what is happening is obtained
- Keep people in the loop as the investigation ensues to maximize compliance and decrease loss of compliance because of boredom or fatigue with the recommendations
As if horse owners and veterinarians in Queensland need another infectious disease challenge.....
Recently, a horse in southwest Queensland was diagnosed with Australian bat lyssavirus infection. This virus, which is similar to rabies, is present in some bats in Australia. It can be transmitted to people from bats, causing fatal disease, but human infections are very rare. Even though it's rare, it warrants attention because the disease is so severe.
Finding an infected horse is surprising in some ways, because the virus has never been detected in this species before. However, a virus that's present in bats can certainly find its way into a horse, and we already knew that a closely related virus (rabies) can infect horses. So, maybe it's not that surprising afterall.
In this case, the horse was suspected of being infected with Hendra virus initially. While Australian bat lyssavirus can kill people, this diagnosis was actually much better than Hendra virus infection, because horse-human transmission of Hendra is a major concern. Hendra virus infections have high fatality rates and, perhaps most importantly, there are no effective preventative measures that can be taken after Hendra virus exposure. Since Australian bat lyssavirus is so closely related to rabies virus, rabies post-exposure treatment can be used in this case (and is probably effective).
It's unclear whether an infected horse poses much risk to people. The very small number of human Australian bat lyssavirus cases have occured in people who were bitten or scratched by bats. Since this is the first equine case, it's not known if affected horses shed large amounts of (or any) virus. People who had contact with the horse were identified and offered post-exposure treatment. It's reasonable to consider this situation like rabies exposure in the absence of more evidence, and treat people who were bitten or otherwise may have gotten virus-contaminated saliva into their tissues via broken skin or mucous membranes.
Is this the start of yet another new problem?
Most likely, this is just an example of the rare scenario of a virus infecting an atypical host, not the start of a new, common problem. However, it's worthy of attention in case the virus has changed or there is now a specific virus type that can more easily infect horses (both very unlikely). This case also shows the importance of thorough diagnostic testing, particularly when an animal has severe disease.
If you don't look, you don't find.
If you don't find, you can't act.
I've been bitten lots of times, some on the job (including the last dog I saw when I was in general practice) and some off (including a dog down the road a couple of years ago). Fortunately, I haven't suffered any serious consequences. That's what happens most of the time. However, bad things can and do occur after bites.
A paper in BMJ Case Reports (Tumram et al 2012) describes a rather unusual and unfortunate situation. It's about a fatal infection in a 55-year-old Indian woman who was bitten by a mongoose. She was bitten (unprovoked, it seems) on the leg by the mongoose while washing dishes. She went to the hospital a couple of hours later because of pain and swelling in her leg. It's not clear what happened there, but she went back to hospital the next day, and then received antibiotics. However, that same day, she suffered cardiac arrest (a heart attack) and died a few days later. The bacterium Streptococcus pyogenes (Group A Streptococcus) was isolated from some lesions on her legs, leading to a suspicion that she developed a severe and rapidly progressive infection from the mongoose bite.
Various aspects of this case are unusual. Fatal bite infections occur, but they are rare. Involvement of streptococci is rarer still.
Why did this woman develop a fatal infection, especially when she sought prompt medical care? It's hard to say, and there is a "bad luck" component of infectious diseases. She had diabetes and high blood pressure, which probably increased her susceptibility to infection (but lots of other people who get bitten also have these conditions and suffer no consequences). It doesn't appear that she received antibiotics when she went to the hospital originally, but a bite over the leg isn't one that would always be treated prophylactically with antibiotics.
Why did the mongoose bite? That's another good question. Unless you're a snake, mongooses are typically not aggressive.
Where did the bacteria come from? We don't know much about the oral bacterial population of mongooses, but Streptococcus pyogenes is a human-associated bacterium. It's rarely found in animals and I suspect that the strep didn't come from the mongoose. Rather, it was probably already on the woman's skin and introduced into her body by the bite, or she contaminated the wound after being bitten. It's just a guess, and it doesn't change anything, but it makes sense.
This report shouldn't make people freak out over a bite. However, it should serve as a reminder that bad things can happen. More information about dealing with bites can be found on the Worms & Germs Resources - Pets page.
Image: Dwarf mongoose (Helogale parvula) in Korkeasaari zoo (photo credit: Miika Silfverberg, click image for source)
We've just posted a new info sheet about cat scratch disease (CSD), which is caused by a bacterium (Bartonella henselae) commonly carried in the bloodstream of healthy cats. Signs of CSD in people can be quite non-specific, so (as always) it's important to let your physician know if you've been bitten or scratched by a cat if you're feeling ill, so that CSD is considered. Other than proper training and handling of cats to avoid bites and scratches, the next most important component of CSD prevention is flea control.
You can read more about CSD and B. henselae 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 CSD in the posts in our archives.
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.
I have three kids that are all now (thankfully) past the diaper stage. I have no idea how many diapers I changed, but I don't have a huge desire to start doing it again, especially for chickens.
I understand the whole urban chicken concept. I don't actually have many issues with it if it's done right - but that's a big IF, unfortunately. Keep your chickens on your property, don't do it if you have young kids or other high risk individuals in the household, use good basic hygiene practices, feed them right, don't get roosters, and don't run screaming to the newspapers or local politicians if some get eaten by carnivorous urban wildlife. The nuisance and risk of backyard poultry can be limited.
Live chickens inside the house... that's another story.
Chickens aren't house pets in my world. I'm not sure if the chickens benefit at all from living in a house with people, and it's probably actually detrimental in many ways. I'm not sure what the benefit is to people either. Although I haven't seen any studies on this specific topic, it stands to reason that keeping a chicken indoors would be associated with a fairly high risk of widespread contamination of the household with bacteria like Salmonella and Campylobacter, two bugs that cause millions of infections in humans every year.
I'm all for risk mitigation, including using creative (and sometimes off-the-wall) measures - but diapers for chickens? Not so much.
Yet, Pampered Poultry makes diapers for your indoor chickens, and not just run-of-the-mill diapers: they're (allegedly) both functional and fashionable. This isn't the only company that sells chicken diapers either, much to my surprise.
One website states "Our chicken diapers are not just for the fashion obsessed hen. They offer your and your home protection against the inevitable! Our diapers fit comfortably and allow you to enjoy your birds in the house or car [car?] without worry."
Does using chicken diapers make sense?
I have a hard time believing these diapers are very useful. They probably do reduce the burden of pathogens that are deposited in the environment, but they are presumably far from 100% effective at containing all of a bird's droppings. It's also likely that chickens are contaminated with these bacteria on other parts of their bodies. Thinking you've eliminated the risk of household contamination from your pet poultry by using diapers isn't logical. The diapers also need to be changed (risk of more contamination) and disposed (don't we have enough waste already?) or washed (risk of cross-contaminating other items).
If you want fashionable chickens, go ahead and dress them up in diapers. Nothing says haute couture like a chicken walking around the living room in pink floral undies. Just don't convince yourself that you're reducing the infectious disease risk for other animals and people in the house. Better yet, let the chickens be chickens and keep them in a proper coop outside. I've seen too many indoor goats, pigs, miniature horses and other species with profound health problems from owners thinking they're just like people.
Apart from diapers, the store also sells "saddles" for the chickens. I'm not even going to start on that one.
I’ve received a lot of emails over the past 24 hours about the recent report of equine herpesvirus type 1 (EHV-1) neurological disease in an Ontario horse. The two main questions are whether there’s an outbreak and whether horse owners in Ontario should be concerned.
I don’t have any firsthand knowledge about this case (or any information beyond what’s been written elsewhere), but as far as I know, this is just a single sporadic case. That doesn’t mean an outbreak can’t occur, but most often, these just occur singly.
Whether there’s cause for concern is a tough question to answer. Yes, EHV-1 can be a serious problem, causing neurological disease in adult horses, abortion in pregnant mares, and severe disease in neonatal foals. Yet, at the same time, it’s an endemic disease that most often occurs as sporadic cases rather than large outbreaks (people just don’t hear about single cases as often, although they are now reported a lot more than they were a few years ago). The EHV-1 virus is very common and can be found in its dormant form in a large percentage of horses, so it’s not like some pathogens with which an unexposed population can suddenly be threatened when a single case is identified. In general I pay close attention to EHV-1 cases, but they are not a cause for panic. If a case occurs, we need to see if some broader issue is at play, and put steps in place to limit the problem, but we don’t need to cause massive disruption. In short, we want to ensure that good surveillance and infection control measures are in place, but not freak out in the process.
People have really taken a 180 degree turn in how they handle EHV-1 over the past 10 years or so. I don’t think we see EHV-1 neurological disease any more than when I was a resident. Back then, we saw sporadic cases and the odd small cluster, and people didn’t get too worked up about it in terms of the risk of transmission. Outbreaks, such as one I can remember associated with a large Ontario Standardbred yearling sale, certainly got lots of attention, but it was short-lived. Things changed (for good reason) based on some large, high-profile outbreaks in the last decade. It’s not known why such outbreaks now seem to be more common.
Anyway, if you live in Ontario and have a horse, don’t panic. Your horse is probably at no greater risk today than it was last month, assuming it wasn't in contact with the affected horse (which was diagnosed in early April). Virtually every horse is at some degree of EHV risk every day, but the odds of disease occurring are very low.
Some key prevention tips include:
- Use good general infection control practices to reduce exposure of horses to pathogens brought in by newly arrived horses.
- Observe your horses regularly and if there are any problems, isolate the horse and have a veterinarian examine it ASAP.
- When travelling to shows, races or other events, take measures to reduce direct and indirect contact between horses.
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.
Allegedly, spring is here. The foot of snow on the ground and minus double-digit temperatures don’t really convince me, but the calendar can't lie, I guess.
Anyway, spring brings with it many things, one of which is hatching chicks. I saw signs for them at a local farm supply store a couple of days ago, and perhaps not coincidentally, this week’s edition of CDC’s Morbidity and Mortality Weekly Reports provides an update on the 2012 human Salmonella outbreak that was linked to contact with chicks and ducklings from a single supplier.
This outbreak has been talked about before, but this report gives some final numbers.
- Ultimately, 195 people infected with the outbreak strain of Salmonella Infantis were identified. (That’s probably a major underestimation too, since in outbreaks like this lots of people get sick but don’t have fecal cultures for Salmonella performed.)
- 33% of affected individuals were children 10 years of age or less.
- 79% of people who got sick reported contact with poultry in the week before illness started.
- Birds were obtained from various feed stores or directly from hatcheries, and 87% of people that provided information about chick or duckling sources reported getting them from a single mail-order hatchery in Ohio.
Chicks and Salmonella go hand-in-hard. Chicks are high-risk for shedding the bacterium, and people can get infected by handling chicks or having contact with their environment. Children are at high risk for infection since they tend to have closer contact with chicks and because they are more susceptible to Salmonella. That’s why it’s recommended that kids less than 5 years of age not have contact with young poultry. Day cares and kindergartens planning on their annual hatching chick programs… please take note.
The article includes some more recommendations.
- Feed stores should use physical barriers (e.g., a wall or fence) between customers and poultry displays to prevent direct contact with poultry.
- Educational materials warning customers of and advising them on how to reduce the risk for Salmonella infection from live poultry should be distributed with all live poultry purchases
Part of the last point is keeping young kids away from chicks and stressing good hand hygiene practices. Like most things in infection control, a little common sense goes a long way.
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).
Today, we went to the University of Guelph's annual open house, College Royal. As per usual, we only covered a fraction of the events, but had to do the traditional visits with the animals and get some of the Food Science milkshakes (even thought it was -2C outside). Animals are a big part of College Royal. In most cases, you can look but not touch (e.g. Old MacDonald's barn, livestock shows), but there is a petting zoo.
The petting zoo has evolved a lot over the years. I was in charge of it for a couple of years when I was a veterinary student, but what we do now is very different from what we did then (in the mid 1990s).
- We've stopped using certain kinds of animals. Most notably, the calves (i.e. baby cows) are gone, since they're considered high risk for transmitting a few important microorganisms. The thing that triggered that was the year we decided to test fecal samples from the calves and found out (not too surprisingly, really) that all of them were shedding Cryptosporidium.
- We've changed the location, for a few reasons. The old location was in a ward in the large animal hospital, which therefore had the potential to impact patient care. The current setup is outside of patient care areas, and makes it easier to contain activities and visitors, and to organize overall.
- Signage has been improved. We used to have many signs, but they mainly provided just basic information about the animals (e.g. "Hi, my name's Betsy. I'm a Holstein cow.") I don't remember having many signs (if any) about hand washing, no food or drink, and other public health measures, but thankfully they do now.
- Hand hygiene is a priority. We didn't really do anything in terms of promoting hand hygiene at the event in the 1990s. Now, we have multiple hand hygiene stations, signs to tell people to wash their hands, people reminding visitors to wash their hands, and a structured flow of traffic through the petting zoo that leads people out past the hand hygiene stations.
Big changes, and for the better.
Has anyone ever gotten sick from the College Royal Petting Zoo? Not that I know of, but it's certainly possible.
Have we eliminated all risk? No. That's not possible. What we try to do is to reduce it as much as we can.
Are all petting zoos like this? Unfortunately no, they are not. Things at other petting zoos are much better overall than they were even five years ago, but there's still lots of room for improvement and still an unnecessarily high risk of infectious diseases.
A lawsuit filed recently in North Carolina highlights some of the issues around petting zoos. The suit was filed in response to a 2011 E. coli outbreak associated with the NC State Fair that sickened more than 100 visitors and killed a two-year-old boy. Among the claims in the suit are:
- animal areas were cleaned in such a manner that E. coli was spread around
- eating and drinking were encouraged in the animal area (presumably, the actual issue is that eating and drinking were not prohibited. I doubt the fair said "please eat and drink in this area")
- there were inadequate hand hygiene stations
- they failed to follow the State Fair's own guidelines
If these claims are true, that's a pretty big "oops" and someone is probably going to be writing a very large cheque.
On a similar note, a UK petting farm was recently found liable for a 2009 E. coli outbreak that sickened 93 people.
Petting zoo design and operation aren't foolproof, but it's not rocket science either - it's largely common sense. There are clear guidelines covering the basics, and adhering to them should greatly reduce any risk of illness or injury. Failing to do so leads to trouble, of both the infectious disease and legal kind.
I write a lot about reptiles, and while it's usually in the context of their biohazardous nature, I actually like them. I've owned some before and it's not outside of the realm of possibility that we'll get more in the future (I might be safe with that statement since Heather doesn't read this blog. However, her co-workers that do will likely rat me out).
Reptiles can be good pets in some situations. The key is understanding and accepting the risk. That involves understanding the risks associated with reptiles, understanding the types of households where the risk is high, and knowing what to do to reduce the risk.
Denial isn't an effective infection control measure.
- Uh...no. Reptiles are clearly higher risk when it comes to Salmonella. Reptile contact has been clearly and repeatedly shown to be a risk factor for human salmonellosis. Dogs and cats (and various other animals) are potential sources of salmonellosis, but while many more people have contact with dogs and cats, reptile contact is much more likely to result in Salmonella transmission. It only makes sense. Reptiles are at very high risk for shedding the bacterium. Dogs and cats rarely do (especially when they're not fed raw meat).
"She’s never seen a case in the 30-plus years she’s been working with reptiles."
- Ok. So, since I've never actually seen influenza virus, I'll never get the flu?
- I know a lot of infectious disease physicians who have had a very different experience. In fact, it's rare for me to talk to an infectious diseases physician without him/her providing details of various reptile-associated salmonellosis cases.
Talking about the risk of Salmonella shouldn't be taken as insulting or a threat to reptile enthusiasts. People should accept that the risk is present and try to minimize it. The article actually has some useful information along those line. "Just use common sense - wash hands thoroughly after handling the animal or its cage. A good rule of thumb is to keep hand sanitizer nearby. While children under age 5 should avoid any contact with reptiles, Hart doesn’t advise snakes for children under age 7 or 8 for fear they could unwittingly harm the creature."
Reducing the risk is common sense. Keep reptiles out of high risk environments and use basic hygiene and infection control practices.
However, any semblance of common sense goes out the door when a rescue like this offers programs where you can pay them to bring reptiles to daycares, pre-schools and grade schools. So much for young kids avoiding contact with reptiles.
Reptiles aren't bad, they're just bad in certain situations. Common sense needs to be more common.
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.
A call to arms from guest blogger and University of Guelph professor, Dr. John Prescott:
Watching the global emergence and spread of multi-drug resistant bacteria is like seeing a train wreck in slow motion. There’s a sense of both inexorability and powerlessness. In the March 2013 issue of the Equine Veterinary Journal, Mark Bowen of the School of Veterinary Medicine and Science, University of Nottingham, writes that there is clear evidence of the need for change in our relationship with antimicrobials. Change is what many bacteria do for a living; of course the problem is not that bacteria change to resistance, but also that people are so resistant to change.
The excellent editorial (“Antimicrobial stewardship: Time for change”) describes the sensible steps taken by the British Equine Veterinary Association (BEVA) in 2012 to promote the stewardship of antimicrobial drugs in horses. These steps are summarized on the BEVA website: http://www.beva.org.uk/useful-info/Vets/Guidance/AMR. They provide an excellent approach to stewardship of antimicrobials in horses. BEVA has developed neat and simple promotional material to help equine veterinarians using these drugs do their part to help preserve them.
The BEVA project is summarized by the acronym PROTECT ME, which encompasses 9 steps to promote stewardship. PROTECT comes from for Practice policy; Reduce prophylaxis; Other options; Types of drugs and bacteria; Culture and sensitivity; Treat effectively, and ME come from Monitor and Educate. The brilliance and perhaps even contrariness of the BEVA approach is that it believes that policies should be created at the local level, and should be both dynamic and follow simple key concepts, rather than be national guidelines developed by people working in ivory towers.
The BEVA website provides the templates and forms for equine practitioners everywhere to develop simple and local policies that commit to stewardship. An important element in the PROTECT ME documents is to try to protect the drugs classified by the World Health Organization as the “Critically Important Antimicrobials” (3rd and 4th generation cephalosporins, fluoroquinolones). These drugs are categorized as “protected”. Drugs such as vancomycin and imipenem are categorized as “avoided”. The PROTECT ME approach promotes the use of “first line” antimicrobials as first choice for treatment of common conditions as part of the practice policy, and link this to the British “cascade” approach to antimicrobial drug choice. The BEVA approach is refreshing because it takes an intelligent, long-term approach that embraces the responsibility that users share to preserve the miracle while our scientists work feverishly to develop the next generation of antimicrobials. These are however going to be extremely expensive and perhaps also unavailable for animal use, except perhaps through the black market.
The antimicrobial “miracle drugs” revolutionized medicine and came into widespread use long before there was any science behind their optimal use. We’re still discovering how best to use them but we need to continue to develop strategies and approaches that optimize their use and minimize resistance and other side effects. The easily followed BEVA approach encourages user engagement with and responsibility for stewardship. Change is painful, but we have no choice. Let’s embrace it.
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.
I'm just back from vacation (luckily, with no infectious disease stories to write), but now I have to catch up on a few posts. One easy one that was waiting for me in my inbox was about Salmonella and hedgehogs.
I've written before about biohazardous hedgehogs, and more details about the US 2011-2013 multi-state Salmonella outbreak were reported in a recent edition of CDC's Morbidity and Mortality Weekly Reports. The outbreak was identified through recognition of a cluster of infections in people caused by the same, historically rare strain of Salmonella Typhimurium. Finding a cluster of the same strain, especially a rare one, suggests that there might be a common source, so an investigation ensued. Here are some highlights:
- Twenty people from 8 states (Alabama, Illinois, Indiana, Michigan, Minnesota, Ohio, Oregon and Washington) were affected, although (as is typical) it's almost guaranteed that many more people were affected but not tested.
- Young people were more often affected, with the average age being 13. The age range spanned from less than 1 year to 91 years of age.
- Four people were hospitalized and one died.
- 14/15 (93%) people interviewed reported direct or indirect contact with a hedgehog. That's a pretty strong indication that hedgehogs might be involved, since that number is wildly disproportionate to the percentage of people in the general population that have contact with hedgehogs.
- Hedgehogs were obtained from various breeders, not from a single source.That's not uncommon since breeders often get animals from other breeders or suppliers and a point-source of infection further up the supply chain is likely.
For some reason, hedgehogs are high risk pets when it comes to Salmonella. High Salmonella shedding rates have been identified in studies of healthy hedgehogs and it's clear that contact with healthy carriers can lead to human infection. Hedgehogs should be considered alongside reptiles in terms of pets that should not be present in high risk households (households with kids less than 5 years of age, elderly individuals, pregnant women or people with compromised immune systems). Hedgehog owners should take care to avoid direct and indirect contact with feces and use good hygiene practices to reduce the risk of infection.
It's been quite a while since the last post about MRSA in horses, but rest assured, it's still out there! Not too surprisingly it's also spreading (or at least starting to be found) in new places. A recent report in Veterinary Microbiology (Schwaber et al, 2013) describes an MRSA outbreak at a large animal teaching hospital in Israel. It is the first report of MRSA colonization in horses in the Middle East, although it's possible (and quite likely) that there's more to be found.
The discovery of the problem had a pretty typical progression: there were two horses in the hospital with post-operative wound infections from which Staphylococcus aureus was cultured, and the isolates from both horses had similar antimicrobial resistance patterns, including resistance to all beta-lactam antimicrobials (= MRSA). Validly concerned about the potential for the MRSA to spread among horses and people in the hospital, an investigation ensued - in this case the National Center for Infection Control (NCIC) was actually called in to coordinate the operation.
- They found MRSA in 12/84 (14.3%) horses, of which 11 were in the hospital at the time of sampling, and 1 had recently been discharged from the hospital. Consider though that 44 of the horses sampled were simply from farms from which an MRSA-positive horse had come - so 11/40 horses in the hospital were positive - that's 27.5%!
- 16/139 (11.5%) of personnel at the teaching hospital were positive for MRSA. Fortunately there were no clinical MRSA infections reported in people.
- The MRSA strain that was found in all the horses and most of the people was a very rare type - not the usual sequence type 8 (ST8) we're used to finding in horses in various other parts of the world. This one was an ST5, spa-type t535, SCCmec type V, which is even rare in the human population.
- The primary action taken to get the outbreak under control: increased infection control measures, including isolation of infected and colonized horses which were then handled with contact precautions (e.g. gloves, gowns), discharging horses from hospital as soon as medically possible to decrease transmission pressure, and having a nurse from the NCIC come in to instruct personnel on the measures to be taken, including emphasis on hand hygiene and increased use of alcohol-based hand sanitizer.
- In this outbreak, decolonization therapy was prescribed for all colonized personnel.
The report does not mention whether or not personnel at the hospital were required to submit to being tested and undergoing decolonization therapy. This can be a very tricky issue to handle, and it depends on what the local laws are. In Canada, employees cannot be forced to undergo testing or treatment, but in some other countries MRSA-positive healthcare workers may not be allowed to even work until their carrier status is cleared.
Interestingly enough, just a year or two before this outbreak occurred a study (as yet unpublished) had been carried out in the same region, during which they found MRSA in 7.2% (6/83) of hospitalized horses and none in horses from local farms. There is no mention regarding whether or not the hospital had taken measures to eradicate MRSA from the facility before the clinical infections that triggered the outbreak investigation occurred.
This was a typical MRSA "iceberg" - a couple of clinical cases were triggers for an investigation that found a lot more horses and people were actually carriers. This is exactly why it's important to remain diligent about infection control measures like hand hygiene at all times, so that pathogens like MRSA don't move in "under the radar." The authors of the paper summed it up nicely (although I'd leave out the part about decolonization):
"Strict implementation of hand hygiene, isolation of colonized and infected horses, decolonization
of colonized personnel and above all, constant education of veterinary students and personnel about the importance of infection control measures are required in order to decrease the risk for colonization and infection of both horses and personnel by MRSA and other pathogens."
More information about MRSA in horses is available on the Worms & Germs Resource - Horses page.
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.
When I was in general practice, I remember going into an appointment and being introduced by an owner to his cat named "Big Screen TV." Upon seeing my surprise at the name, the owner explained that the medical emergency the cat had the year before cost as much as the big screen TV he wanted, so he renamed the cat.
If that's the case, then L.A. Times columnist David Lazarus might want to call his cat "SUV." Lararus developed an infection after a cat bite that required surgery and extensive medical care. His hand was saved, at a cost of about $55 000. The article describing the ordeal it is focused on the financial aspect and the bizarre approach to hospital billing in the US, so there's not much information on the bite or the infection itself, but it's yet another example of why preventing bites and good bite care is important, regardless of how serious the bite may appear at first.
One on the things we try to do with the blog approach to getting zoonotic disease and infectious disease information out is to put a personal spin on stories. Whether it's new puppy issues, a rabid bat in my house, zoonotic disease issues at my kid's daycare or something more mundane, that personal touch sometimes helps keep things in perspective.
Knowing more about what we do and why might also help with understanding how our thoughts and opinions come about. An article posted on atGuelph details our own Dr. Maureen Anderson's ascent in the veterinary world from undergrad to infection control researcher, including her groundbreaking infection control surveillance in veterinary clinics. I'll let you read the story yourselves through the link highlighted above...
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.
Santa gives the reindeer a few months off every year, so inevitably they're going to cause trouble.
A health board inquiry is under way after a young reindeer was taken into a Glasgow Children's Hospital and allowed to interact with patients. The reindeer fawn, from a local reindeer farm, was paraded around the hospital grounds as part of an organized event. That's great. The kids could see something unique. However, the problem occurred when a staff member decided to take the fawn inside so more young patients could see it. By doing that, the fawn was turned into a "therapy animal," meaning all the various recommended precautions for a therapy pet should apply (including a prohibition on bringing farm animals into a hospital).
It essence, good intentions + lack of critical thought + lack of clear local guidelines lead to this situation, which has caused an outcry amongst some groups (and probably a similar "so what?" amongst others).
Here are some interesting bits from the article:
"It had been checked by a vet..."
- Okay, good start, but for what was is checked? You can't tell what infectious agents an animal carries by looking at it. We know that young animals are more likely to shed various potentially harmful microorganisms, and deer can be sources of very harmful bacteria like E. coli O157.
"It is understood that the patients who did pet the fawn were later given antiseptic wipes with which to clean their hands."
- I wonder what "later" means. I suspect it wasn't right after animal contact.
“I don’t suppose any animal, no matter how well shampooed and clean it was, should be allowed into a hospital without prior knowledge and the correct arrangements made,” [Dr. Jean Turner of the Scotland Patients' Association] said.
- A reasonable statement. She's not saying "no animals," she's saying "no animals without a proper plan."
"I think it was well-intentioned, but I don’t think anyone was thinking about the consequences of taking a live animal like that to a hospital.”
- That sums it up nicely.
Every animal (and person) is carrying multiple microorganisms that could make someone else sick. Usually that doesn't happen, and we need to live life, not stay locked up in our bedrooms. However, some animals are at higher risk of shedding pathogens (e.g. young animals, farm animals), some situations make it more likely that an individual animal will contaminate the environment of patients (e.g. interacting with a farm animal, taking a non-house-trained animal inside) and some people are at much higher risk of serious disease when they encounter various bugs (e.g. hospitalized kids).
I'm sure some kids had a great time, and the overall risk was probably low. However, was there really any benefit here beyond a properly run pet visitation program with appropriate animals, established protocols, good hygiene practices and proper handler training?
Pet therapy programs are too important to be compromised by illogical events like this that sometimes cause a knee-jerk "no animals in the hospital" response. That's why there are good international pet visitation guidelines and why people need to follow them.
The fact that Salmonella and reptiles go together is old news. I often get questions about testing reptiles to see if they are Salmonella carriers and I tell people not to bother since even with a negative result, I'd consider the animal to be positive. A recent study in the Journal of Zoo and Wildlife Medicine (Goupil et al 2012) provides more evidence for this.
This study involved testing 12 snakes used in a public educational program, by sampling them weekly for 10 weeks. Here are the highlights:
- 11/12 snakes were positive at least once.
- 58% of snakes were positive on 5 or more weeks.
- On a weekly basis, between 25-66% of snakes were positive.
- Fifteen (!) different types of Salmonella were identified. Nine snakes shed 2 or more different Salmonella types over the study period.
- Two samples from feeder rodents were also positive.
This shows nicely how a single negative sample doesn't guarantee that a snake is truly negative. It also shows how common Salmonella is in snakes. The positive cultures from the feeder mice aren't surprising either, but shows that even if a snake was truly Salmonella negative, it could be exposed at any time through its food, and that there is potential public health risk from contact with feeder mice (something that large international outbreaks of human infection from infected feeder mice have shown).
This study just reinforces some key concepts:
- Assume all snakes are Salmonella carriers.
- Use good hygiene practices around snakes and feeder rodents.
- Keep snakes away from high risk individuals (e.g. the very young, elderly, pregnant, immunocompromised).
- Don't waste your money testing your snake for Salmonella. Focus your efforts on smart and practical management practices.
More information about reptiles and Salmonella can be found on the Worms & Germs Resources - Pets page.
Yes, the title's a bit misleading. Equine herpesvirus (EHV) is everywhere, since the virus circulates widely in the horse population internationally and lies dormant in the bodies of a large percentage of healthy horses. However, cases of EHV-1 neurological disease get attention because of the severity of disease and the potential for outbreaks (for reasons we really don't fully understand). Seeing a report of a new case isn't surprising, since they are always occurring somewhere, but it's worthy of note for horse owners in the area or those who might have visited the area recently.
The latest incident, reported by TheHorse.com, involves a Standardbred horse that raced at Sports Creek Raceway, a small track in Michigan. The animal raced on December 22nd and started showing signs of neurological disease on December 23rd. It presumably didn't pick up the virus at the track, because 24 hours is on the very low end of the potential incubation period, so the main concern is that the horse might have been shedding the virus while at the track. It's possible that EHV could have been transmitted to other horses via aerosols (virus on small particles released when the horse was breathing, shorting or coughing), contaminated items that were used for multiple horses (e.g. buckets), or on the hands or clothes of people. That's why good general infection control practices are needed at tracks and other horse competitions at all times - to reduce the risk of transmission when an infectious but currently healthy animal is present (and there's room for a lot of improvement).
Typically, the incubation period of EHV-1 in a neurological disease outbreak isn't very long: about 4-6 days or so. If anyone had a horse at the track on the 22nd and it's still healthy today (January 4th), odds are it won't be affected. However, there are some instances when the incubation period can be longer, particularly with abortions in pregnant mares. Also, horses could have been infected and not gotten sick, but still be able to spread the virus to other horses with which they subsequently have contact. For this reason, several racetracks have imposed temporary entry restrictions on horses that were at Sports Creek in December. It's probably a low risk situation, but you can never put an outbreak "back in the bottle," and a little short term inconvenience is much better than the major hassles (and deaths) that can come with an outbreak.
The affected horse was in pretty rough shape neurologically but ultimately recovered, as can occur with EHV-1 neurological disease. If your horse has to have a neurological disease, this is probably one you want since full recovery is possible. EHV-1 will probably live within this horse's body for a while, if not lifelong, but that's true of a large percentage of other horses as well, so after a few weeks (when the likelihood of him shedding the virus decreases), he probably poses no more risk than any other horse.
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.
The 15 cm of snow that fell last night is as good of an indicator as any that agricultural fair season is over in this region. But, planning ahead is important (and often not done well with fair petting zoos), so it's never to early to make a plan for next season. Petting zoos can be fun and educational, but are also associated with infectious disease risk. There's always some inherent risk with any kind of animal contact, since all animals (and people) carry a multitude of infectious agents. However, understanding pathogen shedding patterns is useful to help determine the best control measures.
A recent study in Comparative Immunology, Microbiology and Infectious Diseases (Roug et al 2012) looked at shedding of selected pathogens by cattle, sheep, goats, pigs, poultry, rabbits and horses at a California county fair. Here are some of the highlights:
- E. coli O157 was found in one animal. This is the main outbreak concern when it comes to petting zoos, because very low numbers of bacteria are required to cause disease and human infections can be very severe. Surprisingly, the positive animal was a pig, not a ruminant, as would be typical.
- Salmonella was isolated from feces of 3 animals: 2 pigs and 1 chicken.
- Campylobacter jejuni, another potential cause of diarrhea in people, was found in 3 animals: 2 cattle and 1 sheep. The 2 positive cattle were adult dairy cattle and they represented 17% of all tested cattle. That's a surprisingly high rate for adult dairy cattle, in my experience.
- Other Campylobacter species were found in 2 cattle, 3 goats (30% of all goats tested) and 1 chicken.
- Antibiotic-resistant E. coli were common, particularly in pigs.
- The parasites Cryptosporidium and Giardia, and the bacterium Vibrio, were not found.
The study didn't look at other aspects of the petting zoo, such as the types of contacts that were allowed, but based on the pictures that were included with the paper, they weren't optimal. Given the results, the picture of two children in the pen with the pigs (including one child who was sitting on the ground leaning against a pig) should raise some concern.
Does this study change anything? Not really, but more information can't hurt. We know that petting zoo animals can carry pathogens, and we have to assume that every animal in a petting zoo is carrying something that could cause an infection given the "right" circumstances. That's why there's a focus on good general hygiene and infection control practices (especially hand hygiene), along with excluding animals that are at particularly high risk. As the authors say "The study findings should not be interpreted as a deterrent to visit agricultural fairs, but as a reminder that good hygiene and sanitation are critical in these settings."
Following up on my recent post about MRSP in rats, here’s a story about MRSA in an alpaca (Stull et al, Can Vet J 2012). As far as we know, it’s the first report of MRSA in an alpaca (or any camelid).
The report relates to our large animal hospital, where we perform MRSA screening of all horses at admission, weekly during hospitalization and at the time of discharge. It's all part of our infection control program, and the screening is designed to help reduce the risk to horses and our hospital personnel, since this multidrug-resistant bacterium is endemic in the Ontario (and broader) horse population, and outbreaks can occur in equine hospitals.
While alpaca’s aren’t horses, and we don’t see that many of them here, they sometimes get screened anyway since screening is being done on most of the other patients.
This case involved a neonatal alpaca that was admitted with its mother because of severe respiratory disease. The cria (baby alpaca) was very sick and was ultimately euthanized about 36 hours after admission.
Surprisingly, the admission MRSA sample from the cria was positive. In this case, MRSA wasn’t involved in the animal's illness. The cria didn’t have any evidence of bacterial infection, so this was an incidental (but interesting) finding.
When the bacterium was tested further, it was classified as CMRSA-5 (Canadian epidemic MRSA-5), a human strain that also predominates in horses in North America. The mother alpaca was MRSA negative. Presumably, the cria picked up MRSA from the farm environment or a person shortly after birth. MRSA (especially CMRSA-5) carriage rates are high amongst horse owners and horse vets compared to the general public, and it would have been nice to have determined if there were any horses on the alpaca’s home farm, but we couldn’t get any follow-up information.
This single case is probably of limited concern in the grand scheme of things. It’s likely an "oddball" infection rather than an indication that MRSA is a serious threat to alpacas, or that alpacas are a relevant source of human MRSA infection. However, that’s largely what was said when MRSA was first found in horses in the late 1990's and early 2000's, and it has since become a significant issue in that species, so the potential for MRSA to become a problem in alpacas can’t be completely dismissed.
If nothing else, the occurrence of this case is an indication of the need think broadly when it comes to infectious diseases, since many pathogens don’t have species boundaries. CMRSA-5 is a human-origin MRSA strain, but it’s worked its way outside of its natural host. It’s not the first and certainly won't be the last bug to make its way from people to animals.
This story's a couple of weeks old, but Sonoma County (California) residents have been warned about an outbreak of salmonellosis in songbirds. Outbreaks of salmonellosis occur occasionally in songbirds such as finches, and can result is lots of sick and dead birds. There are also risks to other species, including cats and people.
Why cats? Cats can be exposed to Salmonella from eating infected songbirds, and sick birds are typically a lot easier to catch than healthy ones.
Why people? People can be exposed to Salmonella from areas the birds have contaminated, particularly bird feeders and their vicinity. People have been advised to remove bird feeders or clean them regularly, and to promptly remove dead birds from under feeders.
- Removing bird feeders temporarily might help keep birds (including sick birds) farther away from people. It's not going to hurt the birds since other food supplies are typically abundant.
- Washing feeders can reduce the Salmonella burden but it could also increase the risk to people if they contaminate themselves while washing them. Certainly, people should not wash bird feeders inside the house, especially not in the kitchen sink. They should also take care to avoid contaminating their clothing and make sure they wash their hands thoroughly after finishing with the feeder.
"Songbird fever" is a colloquial name for salmonellosis in cats - a testament to the potential for feline infection. It's uncommon but can be severe, and cats can act as a bridge between sick birds and people by bringing Salmonella into the household. This is just one of many reasons why domestic cats are better off living indoors.
A year or two ago, I received an email from Dr. Chelsea Himsworth, who was doing some interesting work looking at different bacteria found in rats in Vancouver's Downtown Eastside. This is an impoverished urban neighbourhood with lots of homeless people, IV drug users and HIV-infected individuals... and lots of rats. Dr. Himsworth, a veterinary pathologist working on a PhD at the University of British Columbia, is assessing potential health risks posed by rats to this type of population. The reason she got ahold of me was to see if I was interested in looking for some different bacteria, like methicillin-resistant staphylococci, in these rodents.
If you look, you often find, and that was the case here with methicillin-resistant Staphylococcus pseudintermedius (MRSP). This multidrug resistant bacterium was found in nasal or oral swabs from 2.1% of rats (Himsworth et al, Emerging Infectious Diseases 2013). So it was relatively uncommon but certainly present.
One question: from where did it come? Most MRSP isolates found were the same as the most common strain found in dogs, so presumably the rats picked it up directly or indirectly from pets or stray dogs. However, there was also a type we've never run across before. That could mean that there is a separate rat-associated MRSP strain, but more likely it means this strain is present in dogs in Vancouver and we just haven't found in dogs elsewhere yet (there aren't many of us typing MRSP, and we find new strains not uncommonly). While dogs and rats presumably don't spend time lounging around together, there is certainly potential for direct or indirect contact between dogs and rats, and rats have been found to harbour dog-associated oral bacteria in the past.
Another question: what's the risk to people? The risk of infection is probably limited, but not zero. MRSP can cause infections in people but doesn't do so very often. MRSP is unfortunately becoming fairly common in dogs, so people are commonly exposed, yet human infections are still rarely diagnosed. So, the risk to humans from these rats carrying MRSP is pretty low overall, although we'd rather not see new reservoirs for this bug.
What about the rats? Rats may be the innocent bystander here, having been infected by dogs. We don't know whether MRSP causes infections in rats. It probably can in certain circumstances.
Can rats spread this to dogs? I guess it's possible. Rats are probably not contaminating the environment too heavily with this bug from their noses or mouths (compared to dogs), but direct transmission if a dog caught a carrier rat could certainly be possible. The risk to the dog population is pretty low since this pathogen is well established in dogs already and there's a lot more dog-dog than rat-dog contact.
Why does an antibiotic-resistant bacterium live in these rats when they're not receiving antibiotics? Good question. Antibiotics certainly help when it comes to selecting for resistant bacteria, but they're not absolutely required. There are a lot of other factors that can also play a role, so rats don't need direct or indirect exposure to antibiotics to acquire MRSP (or other multidrug-resistant bacteria). It could be that they are just commonly exposed and the bacterium only hangs around for a short period of time, or that there are some other factors in the rats, their food or their environment that select for these resistant bacteria.
If you're in Toronto (or probably anywhere in Canada), you've probably heard a lot about Darwin, also known as the "Ikea Monkey". Darwin is a seven-month-old rhesus macaque (Macaca mulatta) that was found wandering around an Ikea parking lot on December 9 in a designer winter coat. He was seized by Toronto Animal Services since non-human primates aren't legal pets in Toronto, and the owner has been fighting to get him back ever since. She has organized protests. She's filed lawsuits. She's planning on moving to a neighbouring region that currently does not prohibit non-human primates as pets. Of course, not wanting to be known as the home for wayward monkeys and their wayward owners, that very region is in the process of enacting a bylaw banning such pets. Darwin's owner is trying to get him back and move ASAP because the bylaw will not apply to existing pets already living in the region when it comes into effect.
For this post, I'll stay away from some of the stranger aspects of this fight and the exotic pet issue in general, and address one basic question: are rhesus macaques good pets?
That one's easy. No.
Why? There are a variety of reasons.
Number one on the list is Cercopithecine herpesvirus (also known as herpes B, herpesvirus simiae or simply B-virus). This is the macaque version of the herpesvirus that causes cold sores in people. It's very common in macaques, and the vast majority of captive macaques are infected. A problem with herpesviruses is that they hang around for life, being shed intermittently and unpredictably. While this virus doesn't cause a major problem in the monkeys, it can cause fatal encephalitis (brain swelling) in people, most commonly after being transmitted by a monkey bite.
Other infectious diseases are also of concern. Bites are a major issue, both from the trauma associated with them and bite infections from the range of bacteria present in the animal's mouth.
Other injuries can be a problem too. While macaques aren't very big, they're strong and they can be aggressive. Injuries to people can happen from aggressive behaviour or over-exuberant play.
The animal welfare aspect can't be ignored either. These animals have complex care requirements. You can't just lock them in a room, toss in some monkey chow every once in a while, and take off for the weekend leaving the neighbour's kid in charge. These animals need a proper diet and care, and that's not something everyone provide. Stress-associated health and behavioural problems are quite common in pet macaques.
The lifespan of these monkeys also needs to be considered. If properly cared for, they can live up to 25 years. That's a long time to deal with a high maintenance animal. What happens if the owner gets sick or dies, moves somewhere that the animal's not allowed, or for whatever reason can't take care of it anymore? That's true for all pets, but the longer the lifespan, the greater the chance of one of these things happening, and harder it is to get someone to take the animal. It's not too hard for someone to adopt Aunt Edna's 15-year-old cat that rarely leaves the couch and isn't going to be around that long. It's different with a young macaque that's going to live many years and require intensive effort for that entire time.
Similarly, a paper co-authored by people from CDC (Ostrowski et al, Emerging Infectious Diseases 1998) states clearly "The extremely high prevalence of B-virus along with their behavioral characteristics make the macaque species unsuitable as pets."
Darwin needs to go to a good sanctuary or zoo, where he can be a monkey, interact with other monkeys, and have a happy, healthy and species-appropriate lifestyle.
Zoo Atlanta has closed its parakeet exhibit after one of the birds died of Chlamydophila psittaci infection. The concern is that this bacterium can cause infection in people (sometimes called parrot fever). Infection of humans is uncommon and usually just causes flu-like disease, but it can be very serious, especially if not diagnosed properly in a timely manner.
The zoo is going to test the flock and decontaminate the facility. The question is, "what will happen if other birds are positive?" Actually, the question probably should be "what will happen when other birds are identified as being positive?"
Chlamydophila psittaci gets the "psittaci" component of its name because it is commonly found in psittacine birds (e.g. parrots, parakeets and other related birds). The dead bird got the bacterium from somewhere, and living communally with other psittacines means that the odds are very good that multiple birds are now carrying it, since birds can carry this bacterium without any signs of disease. Varying carriage rates in psittacines have been reported in different studies, but in some groups (e.g. breeding colonies) rates can be very high.
Concern about the aviary is reasonable, since this bacterium can be spread through the air, mainly through inhalation of contaminated material that's been aerosolized (e.g. dried feces that end up in dust in the air). If there's no direct contact with birds, through, the risk to the public is probably very low. Some management practices can be used to reduce the risk of aerosolization of the bacterium and reduce the risk of exposure of the public. These could include using cage litter that isn't dusty, regular and thorough cleaning of the area and cleaning in a manner that reduces the risk of aerosolizing the bacterium (e.g. wetting things down before cleaning, not using a vacuum unless it has a HEPA filter).
So, what about testing? One of my standard lines is "never do a diagnostic test without a plan to use the results." Hopefully, the zoo has thought about what they'll do with positive results, since it's likely they'll have many.
Testing is a somewhat controversial area. It's been recommended that birds in areas where they will be exposed to a lot of people be tested. That could apply here, depending on how the birds are managed. One issue with testing is it's far from 100% accurate, so it's only one part of the control program and testing limitations need to be understood. Testing makes the most sense in a population of birds that is closed, meaning there are no new birds coming in. That way, a couple of rounds of negative tests can give you pretty good assurance that the group is negative. Positive birds can be quarantined and treated to try to eliminate the bacterium. If most of the group is positive, it makes it pretty difficult to eliminate. A single round of testing or testing and then bringing in new birds doesn't help too much.
Overall, the risk is greatest for zoo personnel who work with the birds and their environment. Good infection control protocols should already have been in place to reduce the risk of disease transmission, but presumably those are being revisited. It's often a controversial subject since use of barriers such as eye protection and an N95 mask are often recommended when cleaning cages, but this is rarely done and there's (reasonable) reluctance to do so because of the rarity of disease, the commonness of the procedures and the fact that people have been doing this for years without these extra precautions. It's a tough area to address and it requires careful consideration of the costs and benefits. Other important points for psittacosis control include avoiding bringing in new birds, avoiding mixing of different groups of birds, checking new birds for signs consistent with C. psittaci infection before bringing them to the facility, quarantining new arrivals and educating people who work with the birds.
One key factor, regardless of what's done, is that people who work with psittacines need to know that they are at increased risk of psittacosis. Their physicians also need to know that they work with psittacines (and that psittacosis is a potential concern). In this situation, people who have worked with the affected bird (and any other bird that might be a carrier) should know to see a doctor if they develop respiratory or flu-like illness.
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.
BMJ Case Reports has a recent paper entitled “Cirrhosis, cellulitis and cats: a ‘purrfect’ combination for life-threatening spontaneous bacterial peritonitis from Pasteurella multocida” (Hey et al 2012). (I don’t think we'd be able to use a title like that in a veterinary journal, but they often get away with titles playing on the animal side in medical journals.)
The case report describes a man who had liver cirrhosis from hepatitis C infection and alcoholism. He went into hospital with a chronic infection of his leg. He’d been seen various times for this problem and various bacteria had been isolated (leading to treatment with various antibiotics). This time, he had severe swelling of his leg that went from his calf to his groin, along with significant accumulation of fluid in his abdomen. Shortly after admission, he deteriorated and became septic (he developed an overwhelming bloodstream infection) and went into liver failure. Blood samples and samples of fluid from his abdomen were tested and the bacterium Pasteurella multocida was isolated. Fortunately, he responded to aggressive treatment.
Upon subsequent investigation, they found out that the patient had a cat, and that cat "had a disturbing habit of regularly licking the serous exudate [leaking fluid] from the patient’s chronic left leg leg cellulitis." (This probably occurs much more commonly than most people think.)
Pasteurella multocida is a bacterium that’s commonly linked to cats, and it’s a frequent inhabitant of the mouth of healthy cats. The cat wasn’t tested but it’s a reasonable assumption that this infection came from the pet. The patient was given “the appropriate advice with regard to the safe cohabitation with domestic animals” but unfortunately they don’t say what that advice was.
This is just one more in a series of reports that show the importance of asking people about pet ownership and pet contact. Asking that question initially can potentially help identify zoonotic disease risks, as opposed to asking the question after the zoonotic pathogen is eventually found when they’re trying to round out the story.
The authors list some ‘learning points’. I’ve copied two important ones below.
- Domestic animals can, under the appropriate clinical circumstances, pose a risk to an immunocompromised host, particularly if adequate hygienic practices are not adhered to.
- Questioning regarding exposure to domestic animals should form part of the clinical history when assessing immunocompromised hosts, allowing early institution of empiric antimicrobial therapy in the appropriate clinical scenario.
They’re both good points, although I’d remove "immunocompromised." While the risk is lower in people with normal immune systems, some risk still remains and pet contact should be queried all the time.
A recent report in the journal Infection (Chean et al. 2012) describes rat bite fever in a patient with AIDS. I’ve written about rat bite fever before, and it’s not really a surprising case report. Streptobacillus moniliformis, the bug that causes the disease, is found in the mouths of most rats (and in the mouths of dogs more often than we’ve previously assumed). Rat bite fever is uncommon but far from rare, and this report focuses on the fact that it was in an AIDS patient. The case report itself isn’t too noteworthy since we know infection with S. moniliformis can happen even in healthy people, and someone with AIDS is going to be at increased risk of any type of infection.
However, there are a few interesting aspects to this particular case. The report described a 30-year-old AIDS patient who had a rather prolonged course of disease with fever, aches, diarrhea and weight loss, with subsequent development of joint pain and swelling. A large battery of tests didn’t identify the underlying cause. Eventually, "it was noted that he had two pet rats, one of which bit the man on his right index finger 1 month prior to presentation." That should have been a "eureka!' moment for the physician. It doesn’t mean the disease was caused by the bite, but it made it clear that rat bite fever should be considered. The diagnosis was then made and the man received appropriate treatment.
While the clinical aspects of the case aren’t remarkable, there are some noteworthy points to consider:
- It wasn’t until re-evaluation that it was discovered that the patient had rats and had been bitten. It’s quick and easy for a doctor to ask “Do you have pets or have you had contact with animals?” and in a case like this, it could have sped up the diagnosis and appropriate treatment.
- The paper repeats the important statement that pet ownership rates among HIV/AIDS patients are similar to that of the general population. That’s also true for other groups at increased risk of infection.
- They say “Physicians need to be cognisant of this [pet/human] relationship in order to prevent missing the diagnoses of zoonotic infections in their patients.” That’s a critical step. It’s easy to do. It’s not often done right.
I haven’t written much about equine herpesvirus type 1 (EHV-1) outbreaks lately because I have a hard time getting excited about them (from a blog writing standpoint… if one occurs here, that will be a different story). Outbreaks of neurological disease caused by this very common equine virus (one that doesn’t spread to people or non-equids) continue to occur, and it’s hard to say whether we've been seeing more of them over the past couple of years or whether we’re just hearing about them more often. It does seem like outbreaks have truly become more common and more virulent in the past 10 years or so, but I’m not sure it’s continuing to get worse.
The latest EHV-1 outbreak has affected 5 of 7 horses on a central Minnesota farm. At last report, one horse had been euthanized and one was hospitalized at the University of Minnesota. The hospitalized horse is presumably receiving supportive care, such as intravenous fluids and general nursing support. Affected horses may become very weak and sometimes they need to be managed in a sling (see photo), since horses don’t tolerate being unable to stand for long (laying down for prolonged periods of time can damage muscles and nerves, simply because they are crushed by the horse's own weight). Sometimes the bladder becomes paralysed and needs to be drained using a catheter. Numerous other problems can occur since the way this disease affects each horse can be quite variable. Fortunately, the prognosis tends to be reasonable (at least compared to other neurological disorders) if the horse is not severely infected and stays standing or is able to remain upright with the support of a sling. The clinical signs are the result of inflammation of the blood vessels in the brain and spinal cord, and the key is to get that inflammation down and keep the horse alive in the meantime.
In the past, we didn’t worry too much about these horses in equine hospitals. EHV-1 neurological disease tended to occur sporadically, not in the form of outbreaks, and dogma was that once the horse was sick, it wasn’t at much risk of shedding the virus. In fact, for a long time our best stall in the main hospital for neurological cases (which had padded walls, and a ceiling anchor for a sling) was right at the front of our main equine ward. A large outbreak in the US in the early 2000s changed that, and now we take much more aggressive measures to contain this virus, including housing affected horses in isolation and using strict infection control measures. With these precautions, the risk of spreading the virus in an equine hospital is low.
Image: A horse with neurological disease being managed in a sling (source: http://coloradodisasterhelp.colostate.edu)
I write a lot about animal bites, and for good reason since they are common and can be very severe. Usually, it’s dog bites. Sometimes it’s cat bites, or more rarely injuries from birds or other critters. Monkey bites not so much, but they happen. I had an email question about rabies exposure from a monkey bite the other day, and there was a paper in the October edition of Emerging Infectious Diseases about monkey bites amongst US military personnel in Afghanistan.
Some highlights of that paper:
From 2001-2010, 643 animal bites were reported by US military personnel.
- More probably occurred since bites are often underreported.
Dogs accounted for 50% of bites, but many other animals were also involved, including rhesus macaques, a type of primate that is present in the wild and also kept as pets in Afghanistan.
- Macaque bites are even more of a concern than dog bites. In addition to the ever-present risk of rabies exposure, these animals can also transmit Macacine herpesvirus B, which is a very serious pathogen that can kill people. Like any animal, macaques also have a wide array of bacteria in their mouths that can cause infections after a bite.
10 monkey bites were reported in this series.
- Most people who were bitten were young (less than 30 years of age) and male. All were junior enlisted personnel or non-commissioned officers.
- Eight of the monkeys that bit were pets, including one that somehow belonged to US military members (despite orders that US military personnel not adopt or interact with local animals or pets).
- Appropriate wound care was provided following only six of the bites. So, there are deficiencies in understanding basic first aid following bites.
- Only five people received appropriate treatment for herpes B exposure. That’s a concern because of how serious this infection can be.
- Eight received antibiotics. Antibiotics are only indicated in a subset of bites, mainly based on what part of the body is bitten, so it's not clear whether this was really needed (while more concerning issues went unchecked).
- Eight received treatment for rabies exposure.
- No one got sick, fortunately.
Monkey bites aren’t something that most people need to be concerned about in their daily lives, but they are a concern for people living in areas where there are monkeys, as well as those who visit such areas. (I have a vivid memory of swinging a camera case at a monkey in Barbados that for some reason seemed to be less than impressed with my existence).
Bites happen, but some are avoidable. Common sense can reduce the risk. If common sense isn’t enough and you’re bitten, don't panic, but you also can't ignore it. After thoroughly cleaning the wound, it's important to get medical advice about what diseases are of concern and whether anything else can or needs to be done. Physicians working in foreign countries also need to be trained on geographically-relevant risks. Monkey-associated infections are not high on the curriculum of US medical schools, so geographically-relevant training is required for people heading elsewhere to work.
Public health personnel in Chapin, Connecticut (USA) are trying to find a woman bitten by a rabid cat. The woman was driving down South Brear Hill Road when she came across a cat. She picked the cat up from the road and told someone else who was there that the cat bit her. She then drove away, and the cat was subsequently identified as being rabid. Now a search is underway to find the woman so she can be given post-exposure treatment.
This is clearly a high risk situation. As opposed to other public health alerts that try to find people who were in contact with a rabid animal on the off chance that they were bitten or otherwise exposed to the virus, this person was bitten and that creates a very high risk of rabies transmission.
The outcome is simple.
- If she gets rabies, she will almost certainly die.
- If she was exposed but gets post-exposure treatment soon (and completes the recommended course), she will almost certainly live.
It's easy to see how this could happen. The woman probably found the cat looking injured or lost on the road, and wanted to help. However, that action, and failure to recognize the risk associated with the bite, have put her life at risk.
A few general rabies reminders:
- Avoid contact with wildlife or any animals you don't know, especially if they seem sick or otherwise abnormal.
- If you are bitten, make sure the potential for rabies exposure is considered. The animal needs to be observed to see if it is rabid, or it needs to be tested. If the animal can't be monitored or tested, you can't rule out rabies and getting post-exposure treatment is the safest course of action.
More information about rabies can be found on the Worms & Germs Resources - Pets page.
I received an email from a relative the other day with a pet question. I get lots of these, but the surprising part is this relative doesn't have any pets (and I think is generally of the opinion that pets are okay, as long as they're not hers). She was asking about turtles. As a responsible prospective pet owner should, she was looking into the issues pertaining to the pet before getting the pet. I think she was more focused on general aspects of care and management, but zoonotic disease risks play into the equation too. This one was a no-brainer, since they have a young child in the house and reptiles shouldn't be present in households with children less than five years of age. So, problem averted, and the need to make a decision later about removing an inappropriate pet from a household was also avoided (along with the awkward "oh, you got a turtle?" Christmas dinner conversation).
But, what happens when people aren't so proactive? Turtles are often passed from house to house as people get bored with them, as they outgrow small aquariums or as parents of young or otherwise high-risk children tune into the Salmonella risks or owning such a pet. If you don't have a friend willing to take your turtle, what do you do?
Petco, a pet products company in the US, has launched a "turtle relinquishment program," whereby they take in "wayward" or unwanted turtles. As of a few weeks ago, 111 people from 10 US states had surrendered their turtles to Petco. The turtles are sent to a turtle farm in Louisiana.
So, this is an option for individuals (at least in the US) with no local way to rehome their turtle. The fact that the turtles are going somewhere to make more turtles (and more Salmonella) is a bit of a concern, but I can see the greater good. Staff at the farm say that turtles are treated for any signs of Salmonella when they arrive. This is a bit strange, since turtles don't typically develop disease from this bacterium - they simply shed it with no signs. Hopefully that doesn't mean the farm is just treating all the animals. It's basically impossible to eradicate Salmonella from turtles, so if they are routinely treating, they're probably breeding drug-resistant Salmonella along with baby turtles.
I know the typical round of emails is going to follow, from reptile advocates who have pretty much done everything except burn me in effigy (or in real life, fortunately). As I've said before, reptiles can make great pets, just not in all households. I've owned various reptiles myself, but reptiles and small kids don't go together. Too many kids get sick every year from pets like turtles. A small number die. That's just unacceptable.
More information about turtles and Salmonella can be found on the Worms & Germs Resources - Pets page.
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.
With the lingering NHL strike, TV networks are looking for replacement sports. One of my PhD students (who claims he doesn't spend too much time playing around on the internet but keeps coming up with these gems) sent me information about one sport that's not coming to a network near you.
Yes, it's ferret legging. That doesn't really seem like a sport to me...more like a fetish or something someone might do when they're really (really!) drunk. Yet, it apparently exists, evolving from its origins amongst Yorkshire coal miners to a not-much-broader audience.
The rules are pretty simple:
- Tie your pant legs securely around your ankles
- Let someone toss two ferrets down your pants.
- Secure your belt.
- Stand there until you can't take it any more.
"Clean the abrasions thoroughly and hope they don't get infected" is the step no one describes. Wounds are, not surprisingly, common, and some people, like world record holder Reg Mellor, wear white pants to show off the blood strains. Mr. Mellor's world record? 5 hours and 26 minutes.
Interest in ferret legging is dwindling, which is probably a good thing for both ferrets and competitors. There's no mention about whether there are any ferret legging family dynasties, but I suspect that regularly shoving sharp-toothed ferrets down your pants severely limits one's chances of reproducing. That's also good for ferrets and humans alike.
An attempt to be inclusive and create a women's competition involving sticking ferrets up a blouse apparently failed - likely due to relative differences in common sense amongst the genders.
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.
In a rather impressive effort - considering the issues inherent with working with a virus like Hendra virus, the nature of the disease and the low economic value of a vaccine that would only be used in a very restricted geographic area - a Hendra virus vaccine has been released for horses. Equivac HeV should provide a degree of relief to people in Queensland and neighbouring areas who have been battling this uncommon but devastating bat-borne viral infection.
As a virus that comes from wildlife, Hendra virus is tough to contain. Eradicating the virus in the bat population isn't really feasible, and while measures can be taken to reduce exposure, the risk cannot be eliminated in areas where the virus is present. So, finding a way to reduce the risk of a horse developing the disease after exposure is critical, and the logical approach is vaccination.
Vaccination of horses can also play a huge role in protecting people. All human Hendra virus infections (approximately 50% of which are fatal) have come from direct contact with infected horses, so reducing disease in horses should reduce the risk in humans.
As with most vaccines, it's safe to assume this one isn't 100% effective. It therefore may be a great tool, but people can't then ignore all other Hendra avoidance practices. Individuals still need to take precautions when working around horses that might be infected, regardless of their vaccination status. So, while it's important to avoid complacency, this vaccine should provide a degree of comfort to people who have been living with this virus hanging over their heads (both figuratively and literally, as bats fly around) in recent years.
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.
Here is another equine update from guest blogger, Dr. John Prescott of the University of Guelph.
Research presented at the Ninth International Equine Infectious Disease conference last week in Lexington, Kentucky, highlighted the dramatic impact that the latest inexpensive genome sequencing techniques are having on understanding microbial disease.
This is well illustrated by an epidemic of S. zooepidemicus upper respiratory tract infection in horses that occurred in Iceland in 2010, described by lead author Sigrídur Björnsdóttir of the Icelandic Food and Veterinary Authority. The infection itself was relatively mild but lasted about 4 weeks, and over the course of the summer affected a large proportion of Iceland’s horses. It caused a headline-stopping movement and export of horses. The disease presented as a laryngitis and persistent dry cough, with a serous [watery] nasal discharge. The infection started at a facility with a water treadmill, and was rapidly disseminated by horses moving from there to 18 other centres across the country, with a high transmission rate to horses within these stables. Since S. zooepidemicus was isolated from the nasal exudate only as the disease progressed, veterinarians investigating the outbreak thought at first that these isolates were opportunistic or secondary invaders, layered on top of an unknown virus infection.
This is where bacteriologists Andrew Waller and Carl Robinson from the United Kingdom’s Animal Health Trust in Newmarket and Matthew Holden from the Sanger Centre in Cambridge became involved. Incredibly, these researchers sequenced the genomes of 290 isolates from the outbreak as well as from an earlier national collection. They used this information to find, to their astonishment, that S. zooepidemicus Sequence Type 209 was responsible for the outbreak. This strain was isolated from the affected farms all over the country, as well as from a case of miscarriage in a person. It could clearly be linked epidemiologically to the outbreak; the date that the infection started was pinpointed to within 5 days. The epidemic occurred so quickly that the genomes of this strain showed almost trivial variation compared to S. zooepidemicus strains that were more established in Icelandic horses.
This is the best description ever of the impact of introduction of a more virulent S. zooepidemicus into a naïve horse population, and will change forever the way that equine veterinarians will think about this underrated pathogen. It illustrates the enormous power of genome sequencing in bar-coding the bad guy.
Andrew Waller also gave a really interesting talk about the diversity of S. zooepidemicus. Sequencing and “sequence typing”, based on multilocus sequence typing (MLST), has identified over 300 sequence types of this species. What is emerging from this is the recognition that difference types cluster with different diseases. For example, strains (sequence types) of S. zooepidemicus that cause abscessation of pharyngeal lymph nodes (“mild strangles”) belong to sequence types that have acquired a bacterial virus carrying a superantigen gene. These are, of course, outclassed by the true strangles organism, S. zooepidemicus subspecies equi, which possesses four bacteriophages with these virulence genes, as well as other nasty characteristics.
Andrew Waller told me that it cost him about $35 to sequence an entire streptococcal genome, which for Canadian veterinarians is now about the cost [Weese comment: or much less than the cost] of sending a swab to a diagnostic lab for culture and sensitivity testing. However, don’t start ringing up the lab to ask for a genome sequence just yet, since the real cost is for the analysis, which is still labour intensive. However, it points the way to the future, which has clearly now arrived, and is changing the way we think about S. zooepidemicus and infection in the horse.
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.
At the recent 9th International Conference on Equine Infectious Diseases (EIDC) in Lexington, Kentucky several sessions were focused on parasite control of horses. Drug resistant parasites are a world-wide problem in equine establishments, and it has become a challenge to define a simple and useful set of guidelines to be used by horse owners. As many readers of the Worms & Germs Blog will be aware, there is no longer a “one size fits all” program, and parasitologists instead often talk about the complexity related to the different parasites that often infect the horses in concert, their interactions with their hosts, and how to interpret fecal egg counts. While this is all useful and important information, it can be frustrating when it does not readily come with some practical guidance.
Equine parasitology is rarely well-represented at parasitology conferences. Usually, there are less than a handful equine abstracts, and often not even enough for a separate session. The three or so participating equine parasitologists often have to create their own little scientific session over a cup of coffee during the breaks. The EIDC was much different. It had participation from leading equine parasitologists from Sweden, Denmark, Finland, Germany, United Kingdom, Canada, Brazil, and the USA. More than 30 parasitology abstracts were presented at the meeting, and a special session critically addressed the most pressing research needs for equine parasite control. During the conference, an international equine parasitology consortium was formed, and it will serve to coordinate future research efforts and to communicate consensus-based guidelines for parasite control.
So, what are these recommendations then? New research presented at the EIDC illustrated very well that general recommendations are more straight-forward than often anticipated. Work performed by Kurt Pfister and colleagues in Germany illustrated that fecal egg counts are useful for monitoring and controlling parasite transmission by the means of selective therapy. Two Danish studies illustrated that one or two yearly strategic treatments applied to all horses are advisable to effectively break the life cycle of large strongyles, particularly the bloodworm, Strongylus vulgaris. In other words, a basic foundation of treatments can be defined, upon which the some of the more parasitized horses can be identified to receive additional treatments with a selective approach. Several presentations underlined the need for yearly routine evaluations of the efficacy of the anthelmintic drugs used on each farm. The fecal egg count reduction test is the most important use of the fecal egg counts. [Weese comment: that's when you do a fecal egg count before and after deworming, and compare the egg counts to see how much they dropped, as an indication of how well the dewormer worked] Perhaps most encouraging was the promising new diagnostic tools presented by several groups for detection of migrating or encysted parasite larvae. These will turn very useful for identifying horses at risk of disease and in need of deworming. One of these, developed by Jacqui Matthews and her group at Moredun Research Institute in Scotland shows great promise for measuring burdens of small strongyle larvae (cyathostomins), which can pose a threat for severe parasitic disease. With these new tools in hand, we will become able to further refine our recommendations in the future.
More from the International Conference on Equine Infectious Diseases, this time from guest blogger and bacteriologist-extraordinaire, Dr. John Prescott of the University of Guelph:
Stellar work on understanding strangles and Streptococcus equi subspecies equi was presented at the Ninth International Equine Infectious Disease conference in Lexington, Kentucky. Researchers at the Animal Health Trust in Newmarket, United Kingdom (Andrew and Carl Robinson) are working with Matthew Holden at the Sanger Centre in Cambridge to use NextGen sequencing to understand better the strangles bacterium, and the impact of the carrier state on the pathogen as it lurks in the guttural pouch. The abstracts of their work are freely available through the conference web site, http://www.eidc2012.com/.
A novel quantitative PCR (qPCR) based on two unique genes of S. equi was was described that will identify S. equi within 2 hours, with a sensitivity of 93% and specificity of over 96%. Not only is it more sensitive than culture but it also overcomes the effects of non-S. equi contaminants which can interfere with culture. Another development reported was an ELISA based on two antigens unique to S. equi that together have a similar sensitivity and specificity to the qPCR. Current thoughts are that the ELISA could be used as a serological test in screening for carriers, with the qPCR then being used on guttural pouch aspirates to confirm the carrier state, which would then be treated.
The strangles (equi) subspecies of S. equi has been thought to be genetically and immunologically identical, but sequencing the M protein SeM gene has shown that there are over 100 strains. Holden and his colleagues have used high throughput sequencing to characterize the genomes of an astonishing 240 isolates from different countries, including one strain from Canada. They have found that genomic diversity is even higher than SeM sequencing had suggested. As a result of this work, they identified a “fitter” clone (ST151) now spreading through the UK population at the expense of an older clone (ST179).
Most interestingly, they have identified the genetic changes occurring as outbreak strains adapt to their different life in the guttural pouch, which is where the organism hangs out in carrier horses. The adaptation involves discarding some genes, stopping the expression of others, but also duplicating others. According to Holden, a Sanger Centre genome veteran, the S. equi genome is more dynamic than any of the other pathogens with which he has worked. The big question is of course the impact of this adaptation on virulence, and the extent and speed with which these genetic adaptations can be reversed if and when the “carrier“ strains revert to cause acute strangles. There is a horrible suspicion that some may be able to borrow back the deleted genes from other S. equi strains in the guttural pouch.
Because of both its species- and niche-adaptation, strangles has all the characteristics of a bacterial infection that can be eradicated. The superb work being done at the Animal Health Trust, all based on genomics, is drawing the noose ever tighter around this ancient scourge of the horse.
- John Prescott, Department of Pathobiology, University of Guelph
Two presentations at the International Conference on Equine Infectious Diseases yesterday discussed equine coronavirus and whether it might be a new or previously unrecognized cause of disease in adult horses. This follows a presentation the day before that mentioned coronavirus diarrhea in racing draft horses in Japan - a rather unique group, pictured at right.
Dr. Nicola Pusterla from the University of California Davis described five suspect outbreaks in boarding facilities from four US states. Seventy-three (73) horses were affected overall, with decreased appetite being the most common sign in affected horses, followed by lethargy, fever, soft manure and colic. Equine coronavirus was detected in the vast majority of sick horses but rarely from healthy horses at the same facilities. Most horses got better without specific treatment, but five horses died or were euthanized. Overall, the attack rate on farms was high but the death rate was low. Fortunately from an infection control standpoint, infected horses only shed the virus for a short period of time (a few days), making control easier.
Dr. Ron Vin followed this presentation with a description of coronavirus involvement in sporadic disease and outbreaks in adult horses from a variety of US states, most often with mild diarrhea and low white blood cell counts. As with the first report, disease severity was usually less than what we see with some other causes of diarrhea in adult horses, such as Salmonella and Clostridium difficile.
One thing that’s not clear is whether this virus is truly a cause of disease or something that’s just being found in horses that have some other undiagnosed disease. No other potential causes were identified in most of the suspected coronavirus infections, but a large percentage of cases of diarrhea that we see go undiagnosed because we don’t know all the possible causes. It’s certainly possible that there was another cause, but these results suggest that equine coronavirus is something for which we should be looking out when we see gastrointestinal (e.g. colic, diarrhea) or non-specific disease (e.g. off feed, lethargic with no other particular signs), especially during outbreaks. The story may be different in foals, since shedding of the virus by healthy foals isn’t uncommon.
Photo credit: http://newshopper.sulekha.com/
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.
In response to an equine herpesvirus type I (EHV-1) outbreak at Hawthorne Racecourse in Illinois, the Ontario Racing Commission (ORC) announced movement restrictions on horses from Hawthorne, and Illinois in general.
- Any horse that has been on the grounds at Hawthorne since Oct 4 is not allowed on any Ontario racetrack until 30 days after Hawthorne's quarantine is lifted
- All horses from Illinois being shipped into the Woodbine or Fort Erie racetracks must come with a certificate that states "Horses represented on this Certificate of Veterinary Inspection have not originated from a barn or premises that is under quarantine for herpes virus, nor have been exposed to a confirmed or suspect case of herpes virus, nor have shown clinical signs suggestive of herpes virus, nor have been febrile within the previous three weeks."
All other tracks are also advised to be cautious about accepting horses from Illinois, but restrictions are at the discretion of individual facilities. The ORC is also recommending that all horses from Illinois are examined and their temperatures are taken prior to being admitted to any track.
Basic physical examination and body temperature checking can be great infection control measures when used on a routine basis. Too many sick horses make it onto tracks, show grounds and into sales, and while checking temperature is by no means 100% protective, it's an easy, cheap and a quick way to identify potentially infectious horses. Yet, it doesn't happen. Considering the potential implications of a single infectious horse making it onto a track, it doesn't make sense that more effort isn't put into routine practices like these. Yes, it would take a couple minutes, but if it prevents one infection (let alone an entire outbreak), it's worth the minimal effort.
As an aside, I've always been baffled why places like yearling sales won't consider employing such measures - well, maybe not baffled because sending sick horses home costs the sale money. But considering how common infectious diseases are in horses after sales, it's hard to understand why buyers are not pushing sales to do what they can to make sure buyers aren't spending big money on damaged goods, i.e. sick horses. I'd like to think that a sale could make it a great marketing point by touting their strong infection control program to convince buyers to come and spend their money with less chance of getting a sick horse.
It's always hard to say what the best approach is for handling EHV infections. On one hand, it's a very common virus that is lying dormant in the bodies of a large percentage of healthy horses, everywhere. On the other hand, we certainly know outbreaks of serious disease happen and horse-horse contact and movement of horses helps outbreaks spread. These Ontario restrictions are pretty straightforward and common sense, but thought should be given to what other measures can be taken on a routine basis to help reduce the risk of EHV-1 outbreaks from developing in Ontario, and to control the numerous other infectious diseases that affect more horses every year.
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.
Earlier this year, a troop of Boy Scouts in the US beat off a rabid beaver that was attacking their leader (I wonder if there's a badge for that). Boy Scouts and infectious diseases are in the news again, but not with as happy a story.
In the recent incident reported on ProMED, ten Boy Scouts that attended a camp on the banks of the Semois River in Belgium developed leptospirosis - a potentially severe bacterial infection caused by Leptospira bacteria. The bacteria are shed in the urine of a variety of animal species, and people can become infected through contact with contaminated water or animals. The boys reported having played with a rat, which was likely actually a muskrat, based on the description of its size.
Three of the boys were hospitalized. Hopefully all are on the way to recovering.
This is yet another reminder that wildlife should be left alone. It's possible the boys were infected from the environment, but handling a muskrat (which was presumably sick if they were able to get that close to it) certainly increases the risk of exposure to a variety of infectious diseases.
Image of a North American muskrat (photo credit: Linda Tanner)(click image for source)
.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.
I’ve written about lymphocytic choriomeningitis virus (LCMV) before, as an interesting but pretty uncommon rodent-associated disease. Human infections are mainly associated with handling rodents, although other routes of transmission, such as organ transplantation from an infected donor, have also been reported. Being a disease associated with rodents and considering how rodents are produced in North America (i.e. mass production in large breeding colonies, followed by transportation to large distributors and massive mixing of animals), LCMV is bound to be a recurring problem associated with the pet rodent trade.
An issue of the CDC's ominously titled Morbidity and Mortality Weekly Report describes the risk of infection with LCMV to people who work in rodent breeding facilities. It all started with the diagnosis of meningitis in a person who worked in a rodent breeding facility in Indiana. An astute doctor suspected LCMV and the diagnosis was confirmed. The breeding facility was a pretty large one, housing approximately 155 000 (!) mice and 14 000 rats. An investigation of facility personnel ensued and approximately 25% of employees had antibodies against the virus, indicating previous infection. A large percentage of the workers reported having had signs consistent with disease (e.g flu-like illness), indicating that they were likely infected and not just exposed.
Considerable effort was put into testing the animals. Of over 1000 animals tested, 21% of mice had detectable levels of the virus in their bodies. That’s pretty impressive and concerning, both for employees and anyone receiving animals from this facility.
In response to this investigation, all mice at the facility were euthanized, and the facility was thoroughly cleaned and disinfected.
This report highlights the risk of exposure to LCMV for people who work with rodents, especially in large facilities such as this. It also highlights the risks posed to people buying rodents from these facilities, which also includes other diseases in addition to LCMV. Good general hygiene and infection control practices should greatly reduce the risk of LCMV transmission to rodent owners. In particular, efforts should be directed at new rodents, since LCMV shedding is probably greatest during the initial period after an animal enters a household or other facility. Virus shedding it often transient, and once they get out of the high-risk facility and become acclimatized to their new home, shedding rates in these rodents probably decrease over a short period of time. Overall, the risk of LCMV in someone with a pet rodent is low, but these basic preventive practices are easy to do and make a lot of sense.
Photo: Female mouse with her litter. (Photo credit: Seweryn Olkowicz) (click image for source)
When bacteria containing NDM-1 (New Delhi metallobetalactamase 1) were first identified a few years ago, I talked about it during presentations as something bad that's coming our way. NDM-1 is an enzyme that gives the bacteria that possesses it resistance to a huge range of antibiotics, to the point that few or no viable treatment options are available. Given the close relationship between animals and humans, I figured it was only a matter of time before cases were identified in animals, especially household pets. A presentation by an FDA researcher at the 2012 Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) has confirmed the finding of NDM-1 in E coli from a pet cat in the US. I can't take much credit for foresight because it was pretty predictable, but it re-affirms concerns about emerging diseases and how infectious pathogens can move between people and animals.
Not much is known about this current case, since the E coli isolate was submitted for testing as part of a large ongoing surveillance study by Dr. Dawn Boothe of Auburn University. At this point, it's unclear whether the cat had been on antibiotics earlier, whether the owner had been diagnosed with the infection, whether the owner had traveled to areas where this bug was first found (e.g. India), and other relevant pieces of information remain unknown (or at least unreported).
The cat was positive for the NMD-1 E.coli on multiple samples. The most intriguing aspect of this case is the fact that the culture samples from the cat were collected in 2008 and 2009 - at least a year before NDM-1 was first identified in the US. That's strange and concerning, and raises lots of questions about where this super-E.coli originated.
Some possible origins of the NMD-1 E.coli in this cat include:
- The owner may have traveled to an area where the bug was present, became a carrier and spread it to his/her cat upon returning home.
- The owner could have been infected when traveling, but it the infection may have been minor such that it didn't require medical care or a culture wasn't taken (so no one knew it was being caused by a super-bug), and subsequently the owner passed it on to the cat. (Remember that NDM-1 is a major concern because very few antibiotics are effective against it. However, the enzyme doesn't make the bacterium that carries it inherently more able to cause disease, so minor infections are possible.)
- On ProMed, the moderator stated that he believes stowaway rodents from India or Pakistan likely carried the bug to the US and spread it amongst other rodents, with eventual exposure of the cat through catching an infected rodent. It's possible but it's a major stretch, in my opinion.
- Perhaps the cat came from one of those endemic regions. That's pretty unlikely but there's a lot of animal movement around the world, with very little regulation, so it is possible.
We may never know how this cat got infected, but this case should be a reminder that we need to pay attention to animal populations in parallel with the human population. I keep saying it, but getting action has been difficult. People like to talk about "One Medicine," but actually getting people to practice "One Medicine" has been easier said than done.
a) there are more rabid beavers these days,
b) rabid beavers have always been around in these numbers but they have recently acquired a taste for human flesh, or
c) it's just a fluke,
The latest incident involved a beaver in West Springfield, Virginia that chased after some kids at a nature centre. The kids had been swimming and saw a beaver swimming towards the dock. It's not that unusual to see beaver's swimming around in some areas, but like most wildlife, they typically stay away from people. Not this one though. It "leaped out of the water onto the dock, acting aggressively and chasing the children." Police shot the animal and testing confirmed it was rabid. Presumably, no one required post-exposure treatment since there were no bites.
While rabid beavers are rare, this and earlier incidents involving attacks by rabid beavers, otters and other critters highlight some basic principles regarding rabies safety:
- Stay away from wildlife.
- Mammalian wildlife that are acting abnormally, including displaying no fear of humans, should be considered rabid until proven otherwise.
- Any bite by a wild mammal should be considered a potential rabies exposure. The animal should be tested whenever possible and if it can't be shown that the animal wasn't rabid, it must be assumed that there was rabies exposure.
Common sense goes a long way toward avoiding rabies exposure, but sometimes it's not avoidable. Knowing what to do in the event of a bite from a wild and potentially rabid animal is important. The key is involving physicians and public health personnel who understand rabies exposure risks, so that a proper risk assessment can be done and treatment can be started promptly if it's indicated.
Image: A North American Beaver (Castor canadensis), by Laszlo Ilyes (click image for source)
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.
When I give talks about pet therapy animals, I talk about appropriate and inappropriate animals. On one slide I have a picture of a hedgehog, and I use it as an example of an animal that sometimes makes its way into pet therapy programs, despite standard guidelines to the contrary. This is a species that raises significant infectious disease concerns because hedgehogs can carry an impressive array of microorganisms that can be spread to humans. A big one is Salmonella.
So, it doesn't come as too much of a surprise that the CDC is reporting a multistate outbreak of salmonellosis associated with hedgehogs. Here are the highlights:
- Fourteen infections have been reported between December 2011 and August 2012. There are probably many more because in most outbreaks, only a minority of affected people get tested.
- People have been infected in six states (Alabama, Indiana, Michigan, Minnesota, Ohio and Washington), all with the same strain of Salmonella Typhimurium.
- All 10 people that were interviewed reported contact with hedgehogs or their environments. Considering the rarity of hedgehogs as pets, that's a pretty good indicator that hedgehogs were the source. The outbreak strain of Salmonella was detected in two households, in areas where the hedgehogs lived or were bathed.
- No one has died, but three people were hospitalized.
- As it typical, a large percentage (50%) of affected individuals were children 10 years of age or under.
The fact that this outbreak appears to have occurred over a long period of time and a large geographic area strongly suggests that this might be ultimately traced back to a common breeder or intermediary source. Many small pets like these are mass produced by large breeders and shipped across the country, creating the potential for a problem at a single breeder to have far-reaching consequences in other breeder colonies and in households. This has been shown repeatedly with species like hamsters and mice.
This report doesn't mean that hedgehogs shouldn't be kept as pets. However, hedgehogs do seem to be a higher-risk species than average, and households that include high-risk individuals (e.g. young children, elderly persons, immunocompromised individuals, pregnant women) should probably avoid them. More importantly, the potential for transmission of Salmonella and other pathogens indicates the need for good basic, routine hygiene practices, such as washing hands after handling a hedgehog, keeping them out of the kitchen, not bathing them in kitchen or bathroom sinks, and supervising contact between hedgehogs and kids.
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 Ontario Ministry of Agriculture Food and Rural Affairs has issued a disease advisory to Ontario equine veterinarians about West Nile virus (WNV), but not in response to cases of WNV in Ontario horses. In fact, to date, there have been no reported cases in horses in the province this year. However, no reported cases only means no horses have become sick and WNV infection has been considered and WNV testing has been performed. It doesn't mean that no horses in the province have been infected, and as much as anything else, the advisory is a reminder to be aware of WNV and ensure that potential cases are properly tested.
While not anywhere near as bad as the situation in some US states, Ontario has had a larger than expected number of human WNV infections this year, and it's reasonable to assume that many equine infections have (and will) also occurred. Since the end of August is typically the start of the WNV season in horses in Ontario, the next few weeks will tell us a lot about the state of this disease in horses in the province this year.
- The Indian River Reptile Zoo near Peterborough, Ontario, rushed some of their stock of snake anti-venom to Brantford General Hospital (about three hours away) to aid in the treatment of a woman who had been bitten by a Copperhead snake. Hospitals in Ontario don't tend to stock anti-venom for snakes that don't live anywhere near here, and it's fortunate for the woman that a couple of zoos in Canada stock anti-venom and are willing to share it (and that those zoos happen to be in Ontario and not the other side of the country). Circumstances of the bite aren't clear but the woman or someone she visited a) is obviously keeping a dangerous snake and b) obviously isn't handling it properly. Indian River Reptile Zoo president Bry Loyst sums up some of the problems with snake bites, saying "Hospitals are amazing but they don't have the expertise right there,” and “You'd be surprised at how many venomous snakes there are out there [in Ontario homes].”
- JayJay, a pet macaque (a kind of monkey) from Okeechobee, FL, was shot after "flipping out" and attacking its owner, "ripping apart his hand." The primate, who wore diapers and played with kids, had lived with the family for nine years, having been acquired at three weeks of age. He got out of the house and his owner was trying to catch him with a net. Whether it was the net, the joy of freedom or some other reason, JayJay lost it and clamped down on his owner's buttocks, thigh and hand, respectively, refusing to let go. A friend had a gun handy (no comment) and shot the monkey at the owner’s behest. The bite on the hand (in particular) was severe and deep, damaging tendons and a nerve, requiring surgical repair. This is another example of the "loving" exotic family pet going berserk for some unknown reason. The macaque often played with kids and the owners took him out in public (e.g. dressing him up and taking him trick-or-treating at Halloween). If we can say anything good about this, it’s good that it was the adult owner who was attacked and not a child. Fortunately, unlike a large percentage of captive macaques, JayJay wasn’t a carrier of herpes B virus, a virus that can rarely cause fatal infections in people. A good closing statement was made by Lion Country Safari wildlife director "Anybody that keeps a monkey is going to get bit... I haven't heard of a monkey that wouldn't bite someone."
- A zookeeper in Berlin, Germany, was killed by a Siberian tiger that had escaped its enclosure. While not a pet, it’s another example of a fatal attack by a captive large cat. As with venomous snakes, there is a remarkably large number of these animals that are privately owned, and attacks certainly happen. Usually, the lucky survivors say it was a "freak incident" and totally unexpected because the animal was like a pet cat. The unlucky ones can’t talk, but often the same story comes from friends and family… the animal was this apparently loving, docile large cat that for some reason attacked. You can never be confident that these animals are safe, because fatal injuries can occur not just with attacks, but with playful behaviour given their size and strength.
- In a related theme, a cougar was shot and killed in Muskoka Lakes, Ontario, after attacking a pet dog. The fact that the cougar had been declawed was a pretty good indication that it was an escaped pet. The owner of Guha's Tiger and Lion Farm, an "exotic animal menagerie" located down the road from where the cougar was shot, says he is not missing any of his cougars, which would "never want to escape" (except, I guess, for the jaguar that was shot by police after escaping in 2008). Since there's no regulation of exotic animals in the province, no one will know for sure from where the cougar came, how many cougars are present in Ontario and how they are being managed. Hopefully Mr. Guha has a containment plan for his other cougars, lions and jaguar that goes beyond assuming they'd never want to leave. If I was a neighbour, I wouldn't be too confident, however, when he says things like "If I leave the gate open for some reason — like I unlock it, then the phone rings so I pick up the phone — if they do get out they’ll go sit by (my front door) and wait for me."
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.
A few years ago, I looked out my kitchen window one holiday morning and saw a newborn foal running outside of a fence line. The foal had been born to my neighbours' mare, a maiden mare, and they were out of town. The mare had rejected the foal and wasn't interested in any of my attempts to get them back together. She also had little colostrum (the first, antibody-rich milk that foals need to drink early in life to survive). To make a long story short, I ended up doing a field transfusion, collecting blood from another horse on the farm to give to the foal, to provide it with those much-needed antibodies. The donor horse was healthy and I didn't know of any disease issues in the area, so I was pretty confident that there wasn't a significant risk of disease transmission, but you never know. Ideally, equine blood donors are screened for infectious diseases, particularly equine infectious anemia (EIA), since EIA is a rare but nasty disease that can be spread by blood.
When I started to read a report the other day about a transfusion-associated EIA infection in a German foal, my first thoughts were "that's bad," followed by my ever-optimistic side thinking "well, maybe it was an emergency transfusion and it was a bad but unavoidable consequence" or "maybe it the donor was properly screened but was infected with the EIA virus after it's last test" (the latter situation is an ever-present risk when you are screening donors in advance (days, weeks or months) of collecting the blood for transfusion, since test results only tell you what their status was at the time of testing).
Unfortunately, it didn't take long to see that this wasn't an unfortunate or relatively unavoidable infection. Rather, I can only interpret this as stunning negligence.
Here's the story
- On August 2, EIA was confirmed in a 3-month-old foal in North Rhine Westphalia. When the foal was two days old, it had a septic joint (and probably an overall deficiency in antibodies) and was treated with a plasma transfusion, which is a pretty standard procedure in such a case.
- EIA antibodies were then detected in the donor.
- Since 2009, 20 other horses had received plasma from this horse. Four have been confirmed as infected, and horses that live with these infected animals have been quarantined until test results are back. Positive horses are typically euthanized because they pose a lifelong risk of transmission of the virus to other horses. The four positive horses in this case have been euthanized (and presumably the foal as well).
So, this wasn't some random emergency field transfusion, or a donor that got infected after testing. It appears that this donor has been used for years with no testing, despite the fact that it's well known that EIA transmission is a risk from blood transfusions and the virus is present (albeit rare) in Germany. While there are no standards of care for equine blood transfusions (as opposed to dogs), EIA testing is a standard recommendation in anything I've seen written about equine blood donor programs (click here for one example). Sometimes you get put into situations where testing can't be done in time for logistical reasons, but I can't see how anyone would not test horses that are to be used for a formal donation program or repeated transfusions. Failure to do low cost and easy EIA screening of that donor horse has resulted in the deaths of multiple horses, with the potential for even broader secondary transmission of this virus to additional animals.
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.
This week an article on TheHorse.com discussed the current situation in the western provinces of Canada with regard to equine infectious anemia (EIA). The prairies are seeing the highest number of EIA cases in years, with more than 70 horses affected on 22 different properties.
Also commonly called "swamp fever," EIA is caused by a retrovirus, similar to the human HIV. There is currently no vaccine against virus, and once infected a horse carries the virus for the rest of its life. Although EIA can cause severe clinical signs (including high fever, weakness, swelling of the lower limbs and along the ventral abdomen, and even sudden death) most horses that are diagnosed are not showing any signs of illness at the time, or may show milder, non-specific signs such as exercise intolerance and intermittent fever. Affected horse of course also have varying degrees of anemia as the name suggests. Episodes of more severe signs can occur even years after the initial infection, and during these episodes an infected animal poses the greatest threat to other horses because the viral load in the bloodstream is very high. The virus cannot be transmitted directly between horses though - it is transmitted by blood, typically via blood-sucking insects like like deer flies, horse flies and stable flies (hence the association of the disease with swamps) or by reuse of needles for injections. Fortunately EIA does not affect humans or any other animal species. It has also not been shown to be transmitted by mosquitoes.
Because infection is life-long, in order to control the disease the only options for positive horses are euthanasia or life-long quarantine in a building with rigorous insect control to prevent spread.
The question is, why the sudden spike in the number of cases out west? There are a few possibilities:
- Possibility #1: There's been one, or a few, small local outbreaks that were initially caused by a very small number of positive horses that likely brought the virus back with them from somewhere to which they had traveled. Hopefully this is the case, and testing has identified all the horses that were subsequently infected so that the virus won't spread further. EIA testing is required prior to travel to many places and prior to participating in many competitions or shows. Regular testing of animals that travel frequently helps to identify infected animals more quickly.
- Possibility #2: For whatever reason, there are a bunch of horses being tested this year that have not been tested in the past, and they're coming up positive. This would be much more concerning, because there's no way to tell how long a horse has been infected if it has not been tested in the past. The longer an infected horse is around outside of a fly-proof quarantine, the greater the chance that an insect (or a needle) will transmit the virus to another horse.
- Possibility #3: There are number of infected horses across the prairies that have not been tested, and the virus has been slowly spreading from these index cases and has finally reached part of the horse population that does get tested regularly. This would be the worst case, as it would mean that there's a reservoir of infected horses that is still not being identified, and could continue to perpetuate the infection.
In the end, only time will tell which of these scenarios (or a combination of them) is playing out in western Canada. Although a relatively low population density (of horses as well as people) in provinces like Saskatchewan helps to decrease the transmission pressure (simply by making it harder for an insect carrying the virus in its mouth parts from one horse to find another horse to bite), gatherings of horses for shows, trail rides and the like (particularly when EIA testing is not required) still create prime opportunities for transmission of the virus.
There are also a few things you can do to help decrease the chances of your horse contracting EIA:
- Protect your horse from biting insects that transmit EIA (which will simultaneously help protect your horse from insects like mosquitoes that can transmit other viruses). Use fly repellants, fly sheets, and avoid turnout during times of peak insect activity (dusk and dawn).
- Never reuse needles, especially between different horses. Also ensure that any other equipment that may be used on your horse (e.g. mouth gags) are always properly cleaned between animals and free from any blood contamination.
- Avoid proximity to horses of unknown EIA status. This can be tough to do if your horse goes to shows where EIA testing is not mandatory, but particularly with the current problems out west (or anywhere else that EIA may be circulating) testing for EIA prior to any event where there will be a gathering of horses should be strongly promoted.
Testing for EIA can be done with a simple blood test. This used to be called a Coggins test, but now a more accurate ELISA-type test is used to test for the disease instead.
Image: Cross-section of the EIA retrovirus (source: USDA Animal and Plant Health Inspection Service)
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.
If I was reincarnated as a mosquito, I'd want to live where I do now (convenient, eh?). I live in the country surrounded by areas of "protected wetland," which, in many cases, is a fancy word for swamp. I try to avoid mosquitoes, but getting bitten is a regular (daily) event. As I was getting swarmed last night, I was thinking that the mosquito-borne disease I'm really concerned about is Eastern equine encephalitis (EEE). While quite rare in Ontario, with only a handful or no cases in horses every year, it's a worry because it's almost always fatal. It also affects people, not via transmission from horses but from being bitten by mosquitoes that pick up the virus from birds. It's very rare in people, but it's highly fatal.
This is the time of year that we start seeing mosquito-borne infections in Ontario, and a Disease Alert from the province re-inforces concerns about EEE. The alert was issued in response to a case of EEE in a horse in New York state, not far from the Canadian border. The horse, from the Ogdensburg, NY area, showed signs of illness on July 23 and died the next day (a pretty typical progression for this disease). Since mosquitoes don't respect borders, cases in this neighbouring region suggest that infected mosquitoes might also be active in Ontario.
EEE isn't the only mosquito-borne virus that we worry about - West Nile virus being the other main issue around here - so mosquito control and avoidance are important. While you can never guarantee that you or your animal will not encounter a mosquito, various things can be done to reduce mosquito numbers (e.g. eliminating sites of standing water (which are mosquito breeding sites) wherever possible... swamps being a logical exception) and to reduce the risk of being bitten (e.g. avoiding high risk areas and times, long clothing, mosquito repellants). Vaccines are available for EEE and West Nile virus in horses (but not people), and the risk of these diseases should be considered when designing a horse's vaccination program.
A short distance down the road from here, the Kitchener-Waterloo Humane Society has been quarantined because of an apparent ringworm outbreak. There's no information on the facility's website and information in the press has been pretty vague (both concerning aspects), but it sounds like a ringworm outbreak. Adoptions have been ceased and the Humane Society will apparently "reassess its safety protocols by the end of the week." The outbreak appears to have been going on since at least last week, so hopefully they're getting on this and have a strong outbreak investigation and control plan in place.
I haven't been involved in this outbreak so I know nothing more than what is in the press, but ringworm can be a big problem in shelters. It's a controllable disease, but the situation can get completely screwed up with a poor outbreak response. It's also sometimes an overblown problem (or not a true problem at all) in some situations, so it's critical that the outbreak is properly investigated and managed. That's not always the case, and the consequences can be serious.
There are a lot of factors that go into good outbreak management that are hopefully being done at the KW Humane Society. These include:
- Good communication both internally and externally.
- Sound containment practices.
- Getting good advice.
- Actually listening to the good advice (and not bad advice).
- Taking the time to do it right.
- Ensuring one is acting on correct information.
- Spending money where it needs to be spent, be it testing, treatment, personnel or other factors. Trying to save money during an outbreak response often ends up costing much more in the end.
The independent report of the 2010 ringworm debacle at the Newmarket OSPCA should be important reading for any shelter trying to figure out what to do, and what not to do.
Rabies is most commonly reported in dogs, skunks, raccoons, bats and a few other species. However, any mammal is susceptible, and sometimes unusual cases are identified.
1. In a serious take on Monty Python's "killer rabbit," a rabid bunny has caused a lot of problems in Chom Thong, Thailand.
The pet rabbit, Poko, had been purchased last year and starting biting the feet of people in the family on June 10. The rabbit was eventually put in a kennel and died July 28. The other rabbit in the house died the next day (no word on why). The time frame is a bit strange, since if the rabbit was biting because of rabies, it should have died a lot quicker. Once an animal is showing signs of rabies, death occurs quite quickly (usually within 10 days), not over a period of 7 or 8 weeks. So, most likely the rabbit wasn't biting because of rabies, at least at the start.
In response to the diagnosis, authorities have launched an investigation and 120 health officials are fanning out in the area to look for other rabid animals, since where there is one, the are others. Dogs and cats within 5 km of the rabbit's home are being vaccinated against rabies. Family members are being given post-exposure prophylaxis. The father has expressed concern that the treatment was too late since they were bitten several days before, but it's not really much of a risk. Rabies typically has a long incubation period, especially with bites to lower extremities, and starting treatment a few days (or even weeks, in some situations) after exposure can still be effective (albeit the sooner the better). The key is for treatment to be started before any signs of rabies develop - after that happens there's very little that can be done.
The source of rabies isn't clear and I haven't seen any speculation. If the rabbit was caged, then there aren't too many possible sources, with bats probably being the most likely.
2. Swimmers beware... it's not just rabid otters you need to worry about.
A man swimming in eastern Pennsylvania was bitten by a beaver that was subsequently identified as rabid. The beaver apparently attacked a canoeist earlier that day, before encountering the swimmer, a Boy Scout leader. The man suffered 15 lacerations from the attack, and the beaver remained firmly attached to the man's arm as he was helped to shore. The stubborn critter wouldn't let go until the resourceful (and brave) Scouts got it off by hitting it with "anything they could find around them, sticks, rocks..." The beaver was killed and confirmed as rabid.
It's another reminder that any bite from a mammal should be considered a possible rabies exposure. It's also a reminder to avoid contact with wildlife, although that can be easier said than done when a rabid animal is involved.
While I'm certain I'll face more wrath from the keep-reptiles-in-schools group that is currently bashing me on the internet (there's even a Facebook page... at least I'm making an impact!), this brings up a few serious issues. One is the whole idea of putting a python around the neck of a young child. I won't go there, and in reality the risk of injury is very low. The main issue is, obviously, Salmonella exposure, because of the high rate of Salmonella shedding in reptiles and the high susceptibility of young kids to salmonellosis. A recent paper in Zoonoses and Public Health (Hydeskov et al. 2012) provides more evidence that the concerns about Salmonella exposure in such situations are valid.
- This study involved the reptile collection at the Copenhagen Zoo. There, the reptile collection consists of two groups: the main group is comprised of animals in the breeding centre, quarantine station and the primary zoo exhibit; the other group is a smaller collection that's used for education and hands-on teaching. The latter group has direct contact with many people, including kids.
- Salmonella was isolated from 35% of reptiles overall, with the highest prevalence in snakes (62%).
- Reptiles from the education group had a significantly higher prevalence than the other reptiles; 64% vs 23%.
- While these numbers are high, they are presumably an underestimation, since other studies have shown that you will miss a reasonable percentage of positive animals if you only test a single sample from each individual. So, it's fair to say that at least 62% of snakes and at least 64% of education-group reptiles were Salmonella positive.
Has the zoo ever been the source of Salmonella in a person? Nothing's been confirmed; however it's important to note that in Denmark, official investigation of salmonellosis cases only occurs as part of an outbreak. Since reptile-associated salmonellosis would most likely occur as sporadic cases, not an outbreak, cases might not be identified and reported.
It's also possible that the zoo hasn't been a source, because of the short-term nature of contact with the reptiles, contact only by older children and their hygiene practices.
At the Copenhagen Zoo, all reptile contact by kids is supervised, and students are required to wash their hands after touching a reptile. That's a great approach (as long as compliance is good), and the risks should be low for a short-term supervised activity such as this. High-risk kids, from an age standpoint, aren't involved since only 7-18 yr old students participate. So, the main group that would be of concern is immunocompromised children, who comprise a small but important subset of participants, and one that may slip by the established control measures since not all immunocompromised kids are readily identifiable. Unless schools know about all high-risk kids (and I'm far from convinced they do) and know that there are things these kids shouldn't do (e.g. have contact with reptiles), there are still some concerns. Those can be lessened further by ensuring that there is good communication between parents and the school, such that schools are really aware of any high-risk kids. That requires adequate knowledge on the part of the parents and the school, good communication in both directions and trust (since private health information is being disclosed). We have a long way to go to get there, and few people seem interested in starting those discussions.
Back to the Guelph paper photo. This wouldn't happen at the Copenhagen Zoo, since they apparently don't let 3-year-olds have contact with reptiles. I wasn't there so I don't know what was done in terms of hygiene, but even if this girl washed her hands after, there would still be a good chance that Salmonella was present on her skin or clothing based on how she handled the animal. This nature centre does some excellent work but I worry about the shows they offer for birthday parties. Their advertisement for this, with the "bring your cake and touch a snake" approach, and the picture of another young child with a snake draped around her raises concerns.
Reptile contact isn't inherently bad. There are just situations when it's high-risk and should be avoided. Beyond that, if it's going to be done, it must be done right. Unfortunately, more often than not, that's not the case.
We’re fully into petting zoo season now, with these types of exhibits appearing at a variety of agricultural fairs and similar events. This also unfortunately means that we’re into petting zoo outbreak season, since there’s always some risk of disease associated with the type of animal contact people have at these displays. There are some basic measures that can and should be taken to reduce the risk of disease transmission, including proper facility design, selection of appropriate animals, good animal health monitoring, sufficient supervision, and above all, providing adequate hand hygiene facilities. Unfortunately, these measures aren’t always implemented - even the really easy ones - be it due to lack of knowledge, lack of interest or downright negligence.
A recent study in Zoonoses and Public Health (Erdozain et al. 2012)(completed under the guidance of Doug Powell and Ben Chapman of BarfBlog fame… or infamy, if you're a particularly slack regulator or politician) evaluated some important public health-related behaviours and factors at petting zoos in Kansas and Missouri in 2010-2011. They found:
- Handwashing stations and signs were present at the exit of 7/13 petting zoos. Yes, it means the majority had them, but it’s a pretty disappointing number. Providing proper hand hygiene stations is easy to do and there’s no excuse for not having them at the exit. The other 6 petting zoos at least had hand hygiene stations within or near animal contact areas, but that’s not ideal. People need to be able to clean their hands on the way out. Doing it in the middle doesn’t help much, and if people have to go out of their way to perform hand hygiene after leaving, it will rarely get done.
- At one event, there was only a sink with no soap, and at another, 2/3 hand sanitizer bottles were empty and there was no area to wash hands. Having hand hygiene facilities is only useful if they are actually appropriately stocked.
- Signs encouraging hand washing were present at the exit of 10/13 petting zoos, but no signs were present at the entrance or entrance to eating areas at any of the venues.
- There were staff monitoring activities at only 6/13 events. At one unsupervised facility, kid goats were able to escape through the fence and were roaming freely.
- When the researchers observed zoo visitors, they noted that only 37% of individuals washed their hands or used a hand sanitizer when leaving. That’s not really surprising, but it’s disappointing nonetheless. People are skipping the best and easiest way to mitigate what is typically the biggest risk factor for pathogen transmission in petting zoos (i.e. contamination of hands ultimately leading to ingestion of pathogens).
- Visitors were almost 5 times as likely to wash their hands when a staff member was present. That’s consistent with a study we published last year and shows the importance of a little encouragement.
- High-risk animals were present in some petting zoos. These included chicks, young ruminants (kid goats) and (a new one for me) a petting zoo that allowed people to enter an area and pet and sit with tortoises.
- People were allowed into animal enclosures in 7 petting zoos, and not surprising, fecal contamination of the ground was common (petting zoo animals not being house trained).
- Various behaviours that might increase the risk of disease transmission were observed, including kids (the human kind, not the goat kind) touching their faces (77% of events), kids eating or drinking in the petting zoo (15% and 38%, respectively), kids eating petting zoo food (7%) and kids sucking on pacifiers (23%). Children were also seen picking up animal feces at one event.
Overall, despite the lessons that should have been learned from various past outbreaks, numerous deficiencies were present, including many that would take little effort to rectify.
The state of petting zoos, at least around here, has certainly improved over the past decade, in part due to more attention from local public health officials, but how do we get more, sustained and widespread improvement?
More strict governmental regulation and enforcement is one way, but that tends to be slow. The more effective approach is probably one that involves the almighty dollar. Most petting zoos are there to make money or bring people to a bigger event that makes money. Like many issues, if consumers start demanding change, change will occur quickly. Maybe that’s easier said than done, but the more pressure that’s put on petting zoo operators and people who run events where petting zoos are present, the more likely it is that change will occur. Visiting a petting zoo can be a great experience, particularly for kids, but we need to make them as safe as possible. Providing hand hygiene stations, some appropriate well-placed signs, having staff supervise, avoiding high-risk animals and logical facility design are easy and inexpensive, and not employing such simple measures is inexcusable.
As with most "pocket pets," guinea pigs don’t get a lot of attention in the scientific literature. As a result, we are limited in what we know about certain diseases in this species, and we tend to rely a lot on personal experience, small case studies and extrapolation from other species. It’s not that these sources of information are bad, they’re just not a replacement for larger, more controlled studies.
A recent study in the journal Mycoses (Kraemer et al. 2012) provides a rather comprehensive overview of ringworm (dermatophytosis) in these little fuzzy critters. The authors surveyed 74 owners of guinea pigs with ringworm and veterinarians. Here are some highlights from the results:
- 97% of ringworm infections were caused by Trichophyton mentagrophytes. Ringworm can be caused by a few different species of fungi, with a different organism, Microsporum canis, being most common in dogs and cats.
- 43% of the time, a new guinea pig was introduced into the household in the weeks preceding the onset of disease, and around one-third of affected guinea pigs had been in the household for less than 3 months. That’s not too surprising, since new animals are often a prime source of infectious diseases. It shows the importance of ensuring that new pets are examined carefully and are healthy before they are brought into the household. It’s certainly no guarantee that there won’t be problems, since healthy-appearing animals can be shedding various infectious agents, but it helps reduce the risk.
- Ringworm lesions were most common around the head. Hair loss was the most common sign, with scaling and crusting also common.
- Signs of ringworm were also present in other guinea pigs in the household in over one-third of cases.
- Various treatments were used and some animals weren’t specifically treated. In fact, 7/8 of the guinea pigs that did not receive specific anti-fungal therapy got better. It's known that ringworm can be self-limiting (meaning the animal will get better on its own over time). However, treatment can speed the process up and decrease the likelihood of transmission to other animals or people.
- In 24% of cases, people in the household also had signs of ringworm, on the head, neck and arms. Children were most commonly involved. That’s not too surprising since kids probably had more contact and closer contact with the animals than their parents.
While not a severe disease, ringworm is a problem because it’s highly transmissible. It can easily and quickly spread between animals, and between animals and people, and elimination of ringworm from a highly contamination household can be a major hassle. Presumably the risk of widespread environmental contamination is less with guinea pigs compared to dogs and cats because of their smaller size and tendency to be kept confined to cages most of the time.
Ringworm should be considered in any guinea pig that develops hair loss or other skin/hair problems. This is particularly true if it’s a new acquisition or if a new guinea pig has been introduced to the household recently.
If ringworm is suspected, a prompt visit to the veterinarian is in order. The guinea pig should be handled sparingly (or ideally, not at all) until the cause of the skin disease is identified. Close attention should be paid to hand hygiene, and even the use of gloves could be considered, although gloves aren’t a cure-all and people sometimes misuse gloves to such an extent that they actually increase the risk of spreading disease.
If a new guinea pig is obtained, it’s ideal to have it examined by a veterinarian before it comes into the household. I’m a realist and realize this is unlikely, but it’s ideal. In lieu of that, it’s important to get a guinea pig from a reputable source, to ensure that other guinea pigs from the same source don’t have skin disease, and to carefully examine the animal for skin lesions before it gets home. It’s also ideal to keep any new guinea pig in its own cage for a couple weeks to act as a quarantine period and allow for identification of any incubating diseases.
If owners of an infected guinea pig develop skin lesions, they should be examined by their physician, and make sure the physician knows they have been in contact with an infected animal.
Vesicular stomatitis (VS) has been reported in a horse in Las Animas County, Colorado. It's the first diagnosed case in the state since 2006, but it's not particularly surprising since this viral disease is periodically identified in horses in various parts of the US, and this case may be associated with northward movement of the virus from the Rio Grande River valley in New Mexico. However, it's noteworthy because VS is a potentially nasty disease and since it's also reportable, diagnosis of a case is accompanied by quarantine and other other control measures.
Vesicular stomatitis typically results in vesicles (small blisters) and ulcers in the mouth, on the tongue and lips, as well as on the udder (udder lesions are more common in cattle compared to other affected species). Lesions around the coronary band of the foot can also develop. Because of these blisters, infected animals may stop eating or drinking, and may be lame. It's a self-limiting disease, meaning it will typically resolve on its own, but animals can develop secondary problems like bacterial infections or severe foot damage, or in some situations the consequences of decreased drinking and eating may be severe, resulting in bigger or longer-term problems. A major concern is that this virus can also infect cattle and produce signs that are similar to the dreaded foot and mouth disease.
The source of infection in this case is not known, but the horse has no history of travel to areas where the disease is active, so insect-borne infection is suspected. That means that the virus must be present in other animals in the region, since blood feeding insects simply spread the virus around, they don't act as reservoirs or amplifiers of the virus. The farm is under quarantine and presumably surveillance is underway to identify other horses that have had contact with the animals on this farm, as well as to monitor for any more cases in the area.
When something like this occurs, travel restrictions for horses (and/or other species) are typically put in place by various governments, ranging from travel bans to requiring animals from areas where the disease is present to be accompanied by a health certificate saying that the horse has no signs of disease and hasn't be on a farm with the disease. Anyone planning travel to, from, or through, involved areas needs to be aware of this and check into transportation rules, including potential import restrictions if they want to enter Canada with a horse.
If you are in an infected region (or nearby), you can do some things to reduce the risk of your horse becoming infected by VS:
- Restrict travel and avoid areas where the disease is active.
- Avoid direct contact between horses as much as possible when visiting farms, shows or other places where horses mix.
- Take basic insect control measures to reduce exposure to biting flies (e.g. black flies).
- Avoid sharing/trading/selling tack and other items that have close contact with your (or any other) horse.
Vesicular stomatitis is zoonotic but it's of limited concern. Human infections are rare and usually just result in flu-like illness.
Sometimes, I get a little concerned when research papers get picked up by the press. It's not necessarily because the research is weak, it's just that results sometimes get overstated or misinterpreted when they work their way outside of scientific forums.
A paper published in the latest edition of the American Journal of Veterinary Research is one of those. The paper (Tsuchiya et al. 2012) describes a study that looked at the impact of interferon-alpha (used to stimulate the immune system) and enrofloxacin (an antibiotic) on body temperature and lung fluid white blood cell counts in 32 horses that were shipped for approximately 26 hours in commercial vans. Horses either received just interferon or interferon and enrofloxacin before being shipped.
- After shipping, 3 antibiotic-treated and 9 untreated horses developed fevers. That's actually not statistically significant, by my calculations, and it's quite strange that the authors didn't do that analysis (and that the reviewers didn't pick that up).
- Two antibiotic-treated and 7 untreated horses were treated with antibiotics after arrival because of concerns about infections. Again, that's not statistically significant and it's surprising (and concerning) no one pointed that out.
- Overall, the average temperature of horses in the treatment group was significantly lower after arrival, but the clinical relevance of that is questionable since it was only a 0.4 C difference. Further, it's hard to say what a temperature immediately after arrival really means, since that's pretty early for a bacterial infection to have developed.
- There were significant differences in tracheobroncial fluid (fluid collected from the airways) between the groups, with lower white blood cell counts in the treated group. That's an interesting finding and is consistent with less inflammation. What that means in terms of disease prevention is harder to say, but it's something worth investigating further.
- There does not appear to have been any difference between the two groups in the ultimate health status of the horses.
This study provides some interesting information to help us think about how, when and why infections and inflammation develop after shipping. Results suggest that antibiotics might be useful in certain situations, but many questions remain. Any antibiotic use runs some risk of complications such as antibiotic-associated diarrhea. It also increases the risk of antibiotic resistance (and ultimately more problems trying to treat disease). We have to remember these issues when considering these results. Further, while it is typically much better to prevent disease than treat it, in situations like this, it's hard to say whether mass prophylactic treatment is actually preferable to early treatment, since horses can be observed closely after arrival and treated when early signs of disease develop. Ultimately, it's still not even clear from these data whether pre-treatment with antibiotics actually does have a positive clinical effect.
It's important to remember what this study tells us, and what it doesn't. Despite what some lay articles that have picked up the story say, it doesn't mean that antibiotics are broadly useful for keeping shipped horses healthy. The authors address this by stating "The use of enrofloxacin raises concerns regarding the emergence of antimicrobial-resistant bacteria, and it is important that antimicrobials such as enrofloxacin are not used inappropriately. The guidelines for enrofloxacin use in the Japan Racing Association’s medical office require that it is only administered as prophylaxis against transportation-associated fever when the duration of transportation is expected to be ≥ 20 hours and the horse has had clinical signs of transportation-associated fever before or is considered to be at risk for developing transportation-associated fever (eg, if the horse has undergone laryngoplasty or has a history of pneumonia)."
Regarding the big picture, however, this should make us think again about how we manage horses. Antibiotics should never be used as a crutch in place of good management. In a situation like this, where 19% of horses treated with interferon and enrofloxacin and 56% of horses treated with interferon alone get sick, something's wrong. Antibiotics may be an easy way to try to reduce the likelihood of disease in some situations, but that doesn't mean it's a good idea. Considering the number of horses that get sick (and die) every year from shipping-associated illness, maybe we need to rethink how they are transported. Is lack of antibiotics the problem, or is it how (and how long) horses are shipped? Maybe long, interrupted trips aren't a good idea, antibiotics or not.
I get a lot of emails about this blog. Some are complementary, some... well... not so much.
When it comes to the latter group, the most common (and often the most grammatically-challenged) group is raw meat feeders. They're a constant source of interesting comments about my intelligence and other aspects of my life. Some actually provide well-written explanations of why they do what they do and I've had some good discussions with a few. Others just like to call me stupid and move on. The guy who provides treatment recommendations for dogs based on fish antibiotics (and his buddies) was another interesting one. The dodgy equine protozoal myelitis clinical trial person (and her friends) was another (she also wrote to my Dean... that's another story). The list goes on.
The latest group has been people upset that I have concerns about reptiles in schools. It seems that a post I wrote a while ago about a school reptile club ended up on a reptile website, whose members are now inundating me with emails. While I appreciate the fact that they are reptile enthusiasts and like their pets, they're missing the big picture.
Yes, reptiles can be good pets, in certain situations. I actually like reptiles. I used to own a few, and the first patient I treated in practice was a reptile.
I've also spoken with people whose children have acquired Salmonella from a reptile. I've read numerous papers about kids that died from Salmonella from a reptile, and I think I've yet to meet an infectious diseases physician who doesn't almost immediately launch into reptile-Salmonella stories when they hear what I do.
The fact is, reptile exposure accounts for a very disproportionate number of Salmonella infections in people, and kids bear the brunt of this. That's why the CDC and various other groups say that reptiles shouldn't be in households with young kids (or the elderly, pregnant women or people with compromised immune systems). The same applies for schools and day cares, where young kids are present, parental knowledge of the exposure is often non-existent, and basic infection control practices are spotty, at best.
No one is saying people shouldn't keep reptiles as pets. However, to me, the evidence is clear that certain people shouldn't have reptiles as pets or be in contact with them. Adults can decide to do things that compromise their health. Adults shouldn't make decisions that compromise the health of their kids or kids for whom they are responsible. Ensuring high-risk children stay away from high-risk animals like reptiles is part of that.
In response to Salmonella outbreaks linked to these critters, their popularity as pets for young kids, and efforts to ban them in some areas, we've developed an info sheet regarding African Dwarf Frogs. As with our other info sheets, it discusses the good and bad points of owning these little guys, things to consider when deciding whether to get one, and measures to reduce the risk of infection.
This info sheet, along with many others, can be found on the Worms & Germs Resources - Pets page in the Information Sheets for Pet Owners section.
The old saying is "when you hear hoof-steps, think horses, not zebras." In a medical context, it means common things occur commonly, so don't start off thinking about wild and bizarre conditions before you've ruled out the usual suspects. Along that line, when I hear "rabies," I think "bats, raccoons, dogs, cats, foxes..." I don't think about... zebras.
Considering there aren't that many zebras in Ontario, and even in places where there are zebras, most people don't have a lot of contact with them, it makes sense that zebras don't typically make the rabies suspect list. But that doesn't mean zebras can't get rabies.
A Letter in Emerging Infectious Diseases (Lankau et al, 2012) describes one such unusual scenario. In January of 2011, an orphaned zebra foal was taken in by a safari lodge (that's probably not too unusual of an occurrence), and not surprisingly, tourists were allowed to handle and feed the foal. Unfortunately, the foal was bitten by a dog at the end of July. The dog was suspected of being rabid but it doesn't seem like any changes were made to how the baby zebra was handed. Unfortunately, the foal died at the end of August and rabies was confirmed. Lodge staff tried to contact people who had visited during the July-August time period, mainly through emails to travel-booking agents who (it was hoped) forwarded the information to travelers.
Several US travelers contacted CDC after getting the email and their risk of rabies exposure was investigated.
- CDC obtained names of 243 travelers who were at the lodge, 136 of whom were from the US.
- They worked with the assumption that the outside window for rabies virus shedding by the zebra was a 14 day period leading up to its death. Seventy-seven (57%) of the US visitors had been there during that period.
- Twenty-eight of those visitors had already started post-exposure treatment for rabies. None of those individuals had high-risk exposures, 2 had moderate-risk exposure while the rest had low or no-risk exposures, so treatment would not have been recommended for most of them. That's probably because the information went from the lodge to travel agents to travelers, and then to the peoples' general physicians (who are generally less well versed in rabies exposure issues) rather than through public health.
- The cost of rabies post-exposure treatment is at least $4000/person in the US (although I know of cases where the cost was much higher), so at least $100 000 was wasted, in addition to stress and other factors.
Some take home messages
- People need to think about animal contacts when on vacation. Travelers that go to rabies-endemic areas need to pay particular attention to avoid high-risk contact with animals.
- Facilities that allow animal contact need to protect the public. Rabies vaccination of this foal might have prevented its infection and the subsequent human exposures.
- If an animal has been attacked by a rabid animal, don't let people come into contact with it!
- Rabies exposure is a medical urgency, not an emergency. There's time to make sure things get done right, and public health personnel should be involved in discussions of exposure and treatment.
The outbreak stretched over a long period of time, from 2007-2009, and involved a strain of Salmonella called Salmonella Java. During the course of the investigation, 75 people with S. Java infection were identified, although there were probably many more infected since diagnosed cases are usually the minority of the true total.
Individuals affected ranged in age from 1 month to 60 years, but the median age was only 2 years, which means the majority were very young children. The investigation started to focus on playgrounds and ultimately 207 sand samples were collected from 39 locations. Thirty-five isolates of S. Java were found, all from 6 playgrounds. These playgrounds had all received sand from the same depot over the preceding year, but Salmonella wasn't found in samples from the depot.
To try to find a source, they started testing critters living in the area of parks, and found S. Java in 34 of 261 animals, mainly from long-nosed bandicoots (a marsupial indigenous to Australia).
It's possible that this Salmonella strain is widely present in bandicoots (and other critters) in the area. I don't know their defecation habits, but if they have a preference for pooping in sandboxes (like cats do), they could be contaminating play areas. The other possibility is that the sand was contaminated from some other source and the bandicoots were infected from the sand just like the people. There's not really any easy way to figure that out.
Sandboxes have been associated with various disease outbreaks, but the overall risk is low and it's certainly not a reason to keep kids away from them. Some things that can be done to reduce the risk of potential disease transmission from things in the sand include:
- Supervising kids to prevent them from sticking things in their mouths.
- Making sure they don't eat or drink in the sandbox/playground.
- Making sure they wash their hands after playing in the sand.
- Covering the sandbox whenever it's feasible (not always an option but good if it can be done) to help prevent animals from defecating in the sand.
More information about sandboxes and potential disease risks can be found on the Worms & Germs Resources - Pets page.
Image: Long-nosed bandicoot from Eastern Australia (Perameles nasuta)(click image for source)
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.
Q-fever, a serious disease caused by the bacterium Coxiella burnetii, is an important concern at petting zoos because small ruminants (sheep and goats) are commonly present at these events and they are the major source of this pathogen. The risk is greatest around adult animal at the time of birthing, and around the new lambs and kids (baby goats), because this is when large numbers of highly infectious Coxiella can be shed. That’s one of the reasons why pregnant small ruminants shouldn’t be part of any petting zoo, but unfortunately this particular recommendation is widely disregarded.
Other than petting zoos, the general public can also have contact with small ruminants through various other routes. An outbreak of Q-fever in the Netherlands (a country with serious Q-fever problems) was reported in association with one of these atypical events, namely "lamb viewing days" on a farm (Whelan et al, Epi Infect 2012).
This farm was open to the public every year during lambing season, and attracted about 12000 visitors from the area annually. Visitors could watch lambs being born (if the timing was right) and interact with young lambs. After finding a cluster of Q-fever cases in the region, an investigation ensued, which compared people who were diagnosed with Q-fever in the region to a group of people without Q-fever. Here are some of the highlights:
- 21% of people with Q-fever reported visiting the farm compared to just 1% of controls.
- When various other factors were controlled in the analysis, having visited the farm meant someone was 43.3 times as likely to have Q-fever compared to someone who didn’t visit the farm.
- Coxiella burnetii was identified in numerous sheep, as well as from 7 of 8 air samples collected on the farm. (Coxiella is a very small, hardy organism that can resist drying, and it can therefore often be found in the dust in the air in areas that have a lot of environmental contamination, like pens where goats and sheep give birth.)
- Specific contacts (e.g. holding a lamb, witnessing a birth) were not identified as risk factors, but the small sample size of people that reported what types of contact they had may have limited the ability to detect a difference.
Visiting farms and having contact with farm animals shouldn’t necessarily be considered a high-risk behaviour. In fact, in some ways it’s a good thing. Greater contact between people and animals and a better understanding of farm animals can be very beneficial. However, we’ve known for a long time that some situations pose an increased and unnecessarily high risk. People organizing farm encounters or petting zoos need to take some basic precautions to reduce the risk to visitors. These are pretty simple and can be done without significantly affecting the visitors' experience. Visitors also need to take some responsibility themselves and follow recommendations, like practicing good hand hygiene and keeping food and drink out of animal areas (just to name a couple). Additionally, the more visitors know about risks and preventive measures, the more they can pressure facilities into doing things right. Public health personnel can work hard to try to improve petting zoos and other events, but nothing will change things quicker than an informed public withholding their money from places that put them at unnecessary risk.
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)
I love my cats. But sometimes when Bonnie and Clyde are living up to their names, puking up hair balls twice a day, peeing on the guest bed (yes, contrary to popular belief even vets can't stop their own cats from doing this sometimes), caterwauling at 3 AM, or begging for food all afternoon, they do make me c-r-a-z-y crazy - but they're not making me suicidal.
In yet another example of how the media will present study results in the manner that will sell the most newspapers or magazines, rather than the way that helps people interpret the results in a logical manner, comes an article entitled "Is Your Cat Hosting a Human Suicide Parasite?" The article talks about a study recently published in the Archives of General Psychiatry (Pedersen et al. 2012) which looked at a cohort of 45 788 women in Denmark who gave birth between 1992-1995, and found a statistically significant association between self-directed violence (including suicide attempts) in these women and their antibody titre to Toxoplasma gondii at the time of birth. The risk in seropositive women was 1.53 times greater than the risk in seronegative women.
Toxoplasma gondii is a parasite that is shed in the feces of cats, which are the parasites definitive host. Most house cats only ever shed significant amounts of the parasite the first time they're exposed to the parasite (typically when they're young). Depending on where people live and various cultural practices, transmission of the parasite from scooping out litterboxes may actually be relatively uncommon compared to other possible sources including exposure from soil (e.g. working in the garden and then not washing one's hands), eating unwashed vegetables, or eating some types of undercooked meat.
The most glaring limitation of the Pedersen study is that they didn't control for any other factors that may have resulted in the women who committed acts of self-directed violence being more likely to be seropositive for Toxoplasma than others. For example, women with mental illness may be less likely to practice good hand hygiene (one of the most important factors for reducing the risk of parasite transmission), and therefore more likely to be exposed to Toxoplasma, or there may be other factors about their health or their lifestyle that make them more prone to infection. The point is the authors only found an association in a specific subset of the population (Danish women who had given birth to at least on child). This does not mean that the relationship is causative - they can't say that Toxoplasma infection makes people more prone to self-directed violence, only that women - in this particular group - who were seropositive for the parasite were also at increased risk for this kind of behaviour. It's a somewhat subtle but very important difference. The authors of the study clearly acknowledge the limitations of their work, but the news article does not do quite as good a job of pointing this out, until right at the very end where it does finally get mentioned.
Does Toxoplasma infection cause behavioural changes in rats that may make them more likely to wander into a cat's territory and be eaten? According to an experimental study it can, and it does make a certain amount of ecological sense that the parasite could have an effect on its intermediate host (the rat) that makes it more likely to be able to continue its life cycle (via being eaten by a cat) by reducing fear in the rat. Could infection of the brain in humans cause subtle behavioural changes? I can't deny the possibility, but humans are not rats and I would be very wary of extrapolating results from one species to the other. But is this parasite likely to "drive our brains off the highway" as the news article says? I'm not ready to buy that, certainly not based on this study. As the authors clearly state in the first line of the paper "Suicide is a tragic multifactorial outcome of mental illness, with complex biopsychosocial underpinning..." There are so many things that contribute to such an unfortunate outcome that a lot more work is needed before anyone can justifiably blame a "suicide parasite" in cats.
Whether you believe Toxoplasma infection can result in behavioural changes in people or not, there are some very simple steps everyone can take to help decrease the risk of becoming infected with this parasite regardless. These are particularly important for individuals who are immunosuppressed and women who are pregnant, because it is very well established that toxoplasmosis in these high-risk individuals certainly can have severe repercusions to either the individual or the unborn fetus. However, it is by no means necessary for such individuals to get rid of their cats if they take these simple precautions:
- Clean your cat’s litter box every day. The oocysts shed in cat feces usually take about 24 hours to become infective once they’ve been passed, so daily cleaning helps remove them before they reach this stage.
- Always wash your hands with soap and water after cleaning your cat’s litter box, after working in the garden or in any soil, and after handling raw meat.
- Keep your cat indoors. Outdoor cats are more likely to be exposed to Toxoplasma and shed oocysts in their stool.
- Keep sandboxes covered so outdoor cats don’t contaminate them with stool.
- Cook all meat, especially pork, lamb, mutton and wild game, to an internal temperature of 67ºC/153ºF or higher.
More information about Toxoplasma can be found on the info sheet on the Worms & Germs Resources page.
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.
Markham, Ontario's city council has passed a bylaw prohibiting the keeping of African Dwarf frogs. While in reality more of a ban on the sale of frogs in the city (since I doubt there will be any effort to search for contraband frogs in households), and perhaps of somewhat limited impact because of the availability of the potentially Salmonella-laden critters in neighbouring areas, not to mention the common practice of pet retailers flouting laws like this, it's nonetheless a step that will hopefully reduce the number of these animals in households.
Why the fuss about African Dwarf frogs?
- Mainly, it's because of the risk of transmission of Salmonella from these frogs to people. Large numbers of Salmonella infections have been linked to these frogs internationally, and the risks are amplified with pets like this that are marketed toward young kids (especially as pets to keep in their bedrooms) and for schools and childcare facilities, because children are one of the highest risk groups for developing salmonellosis.
- The other important issue is animal welfare, since these frogs are often sold in unsuitable habitats and have a fairly limited lifespan in captivity.
Not surprisingly, the owner of the US company that is one of the main distributors of these animals is unhappy with the decision. It's hard to be sympathetic given the fact that they essentially ignore the risks these animals pose to people, at least in the materials they present to the public. Despite the fact that they are marketing what is considered a high-risk animal as a pet, there's little effort put into providing information about that risk or risk mitigation. Looking at their promotional materials, I can find lots of information about how to care for the aquarium. Yet, none of it mentions Salmonella. There's no statement about keeping young kids away from frogs. There's no mention of washing hands after contact with frogs or their environment, or that aquarium water shouldn't be dumped down bathroom or kitchen sinks... or any other basic, relevant infection control practices. They do have some CDC information on their website if you look around, which is better than nothing, but it needs to be more prominent. Everyone that purchases one of these frogs should get a clear information sheet that explains the risk of Salmonella transmission and how to avoid getting sick. Yes, it puts a bit of a damper on the new pet, but a lot less than being hospitalized.
Back in Markham, it's hard to say whether the ban will have an impact on frog ownership because of the ability to buy frogs a few minutes away in neighbouring municipalities, and the likely lack of any real enforcement effort. However, it's a start and if nothing else, and publicity associated with the ban may help educate people. African Dwarf frogs that are already in households are exempt and can live out their natural (albeit often short) lifespans, but people can't replace them when they are gone.
More information about Salmonella can be found on the Worms & Germs Resources - Pets page. We don't have a dwarf frog info sheet (it's coming) but most of the information on the Reptiles info sheet equally apply to frogs.
'Tis the season...
As summer progresses, mosquito-borne infections become more common. While West Nile virus typically peaks later in the summer or early fall, Eastern equine encephalitis (EEE), a much more deadly viral neurological disease, tends to start cropping up earlier in the season.
Recently, EEE was diagnosed in two horses in Horry and Marion Counties in South Carolina, where the virus is mainly transmitted by a type of swamp mosquito, commonly known as the blacktailed mosquito. The outcome isn't stated in the report, but most likely the horses died, since mortality rates for EEE are extremely high.
Finding EEE in a region indicates that the virus is circulating in the bird and mosquito populations. Knowing this is important for a couple of reasons:
- It means that horses might be exposed to the virus by mosquito bites. Therefore, it's a good idea to reduce mosquito exposure by a variety of methods. Vaccination also needs to be considered, but given the fact that vaccines don't protect horses immediately, waiting until the first cases of the year are diagnosed may be too late. Ideally vaccination should be performed a month or so before the time when exposure is likely.
- It also means that humans may be exposed to the virus in the same way - by mosquito bites. EEE in humans is rare but devastating. If EEE is in an area, people need to take proper mosquito bite prevention measures. There's currently no vaccine against this virus for people. People cannot get EEE directly from horses or birds.
Horse owners need to be aware of infectious disease risks for their area (and anywhere they may take their horses), and they need to talk to their veterinarian about the risks and risk mitigation. Not every horse in North America requires EEE vaccination, but in some regions it's very important and should be a core vaccine.
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.
This time of year, it's very common around here to see young raccoons wandering about. It's also still pretty common to hear about people keeping a litter of baby raccoons in their house. I can understand the appeal - they're cute and entertaining. However, in addition to being illegal in many regions, handling young raccoons also poses a risk of exposure to a variety of infectious diseases.
Chief among the infectious disease risks of handling young raccoons is rabies, as a Walker County, Alabama, family found out. Two baby racoons were found in someone's attic, and another two littermates were found a little while later. The person who found them gave two each to two separate people. As is often the case, they were handled by many different individuals before one of the raccoon kits was found to be rabid. Now more than 20 people are facing post-exposure treatment. It's one of the larger reported exposures from a single rabid raccoon, but it's far from unprecedented.
Beyond the obvious public health concern, this situation demonstrates another possible issue. Rabies is sporadically distributed in some regions, and moving wild animals around leads to the potential for dissemination of rabies, as well as other infectious diseases. Raccoon rabies is present in the area where the baby raccoons were found, but has not been found in Walker County, even though it's not far away. If the rabid raccoon had escaped (or was released), it could have potentially spread rabies into an area where it's currently not well established, thereby increasing the risk of exposure to everyone (animals and people) in the county.
As mentioned above, it's also illegal to harbour wildlife in many regions if you are not a licensed rehabilitation facility. While getting fined seems to be uncommon, four people in this incident have been charged with unlawful possession of a protected animal. Just one more reason not to do this.
While baby raccoons may have some appeal, as Alabama's state veterinarian Dee Jones says, "...people just need to stay away from them."
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.
Plague cases tend to get a lot of press. The fact that this disease killed a large percentage of the human population in a few different pandemics (albeit centuries ago for the most part) probably plays a role in that. Despite the impression by some that it's just a historical disease, plague is alive and well in certain parts of the world, including parts of the US, and infects a few thousand people every year.
Plague is caused by the bacterium Yersinia pestis, which lives in various wild rodents and is circulated by fleas. Transmission to people historically has been via fleas that jump from rats to people. However, plague isn't just a rat-human disease, as it can infect other animal species. Among domestic animals, cats seem to be most commonly infected, probably because of exposure while hunting.
The problem with plague and pets has been shown once again a case of plague in an Oregon man who likely picked up the infection from his cat. (Oregon is outside of the main range of plague in the US, where the disease is most common in the southwest). The man was bitten by the cat while retrieving a dried, decayed mouse carcass from its mouth. He developed septicemic plague (infection of the bloodstream), and then pneumonic plague (infection of the lungs), which is the worst case scenario. At last report, he was in critical condition and the prognosis for survival is probably guarded.
There's no mention of the cat's health. Most cases of cat-human plague occur in people taking care of sick cats (especially veterinarians). If a person is infected by a cat bite, I would expect the cat to have been sick with plague, although transmission has been reported from apparently healthy cats. Some other possible routes may need to be considered. If the cat in this case was exposed to plague, then plague's obviously in wildlife in the area, so you have to consider that the infected man might have been bitten by an infected flea (that came directly from an infected wild animal or that the cat tracked in) or from direct contact with wildlife, especially if his house had a rodent infestation.
Regardless, it's important for people in plague-endemic (and neighbouring) areas to be aware of plague and take measures to reduce the risk of exposure for themselves and their pets, such as:
- Avoid contact with wild rodents (and wildlife in general, since larger wildlife species can also be infected).
- Keep cats inside.
- Don't let pets with outdoor access roam unobserved, where they might be more likely to encounter wildlife.
- Have a flea control program for pets.
- Address any animal/household flea infestations promptly and aggressively.
- Make sure sick pets get prompt and appropriate medical attention, since diagnosing plague in a pet may be a critical factor in prompt treatment of people infected by the pet. Plague is an example of a disease for which diagnosing infection in the pet might save the owner's life.