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.
“Show me the peer-reviewed publication.”
This is a common refrain used, particularly by the scientifically-minded, when talking to someone about the latest trendy diagnosis, treatment or other medical "discovery." It used to be relatively easy to use this method to assess the reliability of new information. If something was published in a peer-reviewed journal, it was probably at least reasonably sound (not always, but it did provide a greater level of assurance).
Now, it’s getting tougher.
One reason for this is the proliferation of online journals in particular. Some are legitimate journals that have been created by people that perceived a need in a specific area. Yes, with more research, more journals can be supported. Some good journals reject 50-90% of submissions, and many rejected papers are still valid and indeed important. Having a wide range of journal options is important because everything can’t be published in Science, Nature or the New England Journal of Medicine.
But, there’s a limit.
I review a lot of papers for journals every year. Sometimes, I end up reviewing the same study a few times for different journals, after I’ve recommended rejection previously. Some of these get accepted if they are a better fit for the journal (e.g. scope of the study, priority of the type of research for the journal) or they end up making substantial changes to improve the manuscript. However, I’ve also rejected some papers a few times and eventually seen them published in pretty crappy journals. The sad reality is that marginal research can usually be published somewhere if the authors are persistent. Most people in academia know the strengths of journals in their field and can approach a paper in a "bottom-feeder" journal with care, but the general public doesn’t know that, may not have access to the full paper, and probably wouldn’t be able to assess the quality of the study anyway. So, just knowing that something’s been published in a peer reviewed journal these days only tells you part of the story.
Even worse, thousands of new journals have been created by for-profit groups. That doesn’t inherently mean they are bad, but it’s getting clear that for some, the size of the cheque is probably more important than the quality of research. I get emails from them pretty much every day from one group advertising a new journal, asking for journal submissions or requesting that I serve on their editorial board (yet curiously, I’ve never been asked to peer-review a paper for one). Unsuspecting academics have signed onto editorial boards thinking they were legitimate and have had a hard time getting their names removed once they realize the problems.
Some of these journals use impressive sounding names or ones that are very close to highly respected journals, further confusing the reading public.
All these things make it hard for the average person who wants to explore something a bit further to know what information can be trusted. Not only do you need to think about whether a study is published, you need to figure out if the study is valid and published in a reputable journal where the research was actually scrutinized, not published just because the authors paid a few thousand dollars for the publication fee.
Some of these for-profit groups sponsor scientific conferences that have the same issues. Normally, conference presenters are invited by scientific committees made up of experts in the area and/or are chosen through submission of research abstracts that undergo review. The more dodgy conferences solicit abstracts (I probably get an email a day from these) and get people to attend conferences, but then send them a bill at the end. So, they sucker paying attendees by making the conference look real (sometimes by putting names of high profile people as organizers or presenters without their knowledge) and get more money by charging presenters (thereby getting money from people who will pay to get their research presented or others with good research that are unsuspecting). In the end, you might be left with good research or invalid research, and it’s hard for the average person to sort this out.
How do we get this get under control? I have no idea.
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.
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.
The new puppy, now named Merlin, is keeping things busy around here. (Note to self: avoid getting a new puppy during miserable weather. Standing in pouring, driving rain at 4 AM is not fun. Okay, enough whining.)
Yesterday, I wrote about the new puppy's deworming plan. One thing I forgot to mention was the rest of the "herd." By that, I mean Meg, our 11-year-old Lab. Herd health gets a lot of attention in food animals and to a lesser degree in horses, but many concepts remain important for pets. Specifically, when you introduce a new member into the herd, you might change disease risks or required preventive measures for other members of the herd.
Meg lives a pretty cat-like existence. She sleeps, eats, walks far enough to go outside to pee and, well, that's about it. As an older dog who has very rare contact with other dogs, her risk of exposure to many microorganisms, such as parasites, is limited. However, since we brought a new little furry vector into the house, Meg might be exposed to some things that haven't been much of a concern in the past. Her habit of eating whatever she can find (including poop), increases that risk further. So, what's the herd health plan?
It's not too detailed, actually.
- One thing is making sure that we deworm Meg and we don't just focus on the puppy. She might be exposed to anything the puppy is/was shedding. We're usually pretty lax on deworming her in the winter months, but she'll get a couple of doses of dewormer alongside the puppy.
- Poop removal. Since Meg's a notorious poop-eater, we'll want to remove Merlin's waste promptly. That's pretty straightforward. If she can't find it, she can't eat it. It's also important to make sure that old feces aren't left around, because some parasites require time in the environment to become infectious, so regular feces removal prevents accumulation of infective forms of some. The current temperature is at the lower limit of where Toxocara eggs are able to develop into infectious larvae, and the risk will probably be pretty minimal as the temperature drops over the next few days, but it's not hard to make sure the yard gets cleaned up.
- If we find something in the puppy, then we'll have to consider whether Meg might be exposed or at risk too, and decide whether she needs to be tested or treated.
The other aspect of the herd is the non-canine component of the household (i.e. the kids). The key points for that, in terms of zoonotic parasites, are cleaning up feces from the yard, avoiding fecal contact, hand washing, treating the dogs appropriately to reduce parasite shedding and other basic feces-avoidance measures.
Hide the kids’ toys, tune up the carpet cleaner, get ready for some sleep deprivation… there’s a new dog in the house. Last night, the yet-to-be-named ("he who shall not be named" having been rejected by Heather) little yellow critter arrived. Meg (the existing dog) seems relatively content, or at least resigned. The cat... not so much, but he's already established who's the boss.
So, while I'm momentarily not trying to convince the puppy to pee outside, I’ll take this opportunity to hopefully practice what I preach and describe what we’re doing for things like vaccination, deworming and other infectious disease-related topics.
To start things off: What’s the deworming plan?
- Roundworms (Toxocara canis) are the main concern in puppies. It’s generally a good idea to assume that a young puppy has roundworms, regardless of from where it came and how well cared for it was.
- Canadian parasite treatment guidelines are to treat puppies with a drug that will kill Toxocara worms at 2, 4, 6 and 8 weeks of age, then monthly until 6 months of age. Our little guy is 9 weeks old and has already been treated a couple of times for roundworms, plus he's had one treatment for coccidia (a different parasite that was found on a recent fecal exam). He’ll get another dose of pyrantel pamoate in the next day or two, then monthly until he’s 6 months old. (If someone gets a puppy and it hasn’t been treated like this or its vaccination history isn’t known, it is recommended to give 3 treatments 2 weeks apart, then monthly until 6 months).
- A fecal exam will be done on the puppy in the near future. It’s not an emergency since it won’t impact what I do at the moment in terms of treatment, but it’s good to see if there are any parasites that aren’t killed by the chosen dewormer (e.g. tapeworms) and to detect resistant parasites (i.e. Toxocara eggs still found in feces after appropriate treatment).
- No flea treatment now since he doesn’t have any evidence of a flea infestation and it’s not very likely he’ll be exposed to fleas before the spring based on the current climate where we are.
- No heartworm treatment until the spring either. The Canadian Parasitology Expert Panel (CPEP) recommentaion is for dogs to receive monthly heartworm preventive treatments beginning at a maximum of two months of age. So, I’m not really following that one, but given the time of year, the low prevalence of heartworm in the area he's from and the fact that the puppy wouldn’t have had too much risk of mosquito exposure because of its age and indoor housing, the risk of heartworm exposure this season is very low.
More updates to come, and hopefully not too many descriptions of how to clean puppy feces off of various surfaces.
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.
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).
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.
At a time when there’s much concern about antibiotic use and resistance, and when there’s talk about restricting antibiotic use in animals, it amazes me that some huge, illogical and easy-to-correct loopholes remain in the current system.
The approach to access to antibiotics for animals varies greatly in different countries:
- In some, access to antibiotics for use in animals is tightly controlled, and these drugs are only available from veterinarians.
- In some, pretty much anything is available over the counter.
- In others (yes, including Canada and the US), most antibiotic use must be supervised by a veterinarian (via prescription), but people can still buy certain drugs over the counter and use them however they want - quite an illogical system.
One of the loopholes that allows individuals to use these drugs without veterinary supervision is the ready availability of a range of antibiotics at farm supply stores, feed stores and similar places. I’ve seen lots of completely illogical, ineffective (and ultimately irresponsible) antibiotic use in large animals from drugs obtained this way, with less common (but not uncommon) misuse in pets.
Another small but still relevant loophole is "fish antibiotics." Various antibiotics can be purchased over the counter in pet stores that are marketed for treatment of fish, but are the same as the antibiotics used in other pets (and people). Unfortunately the internet also abounds with descriptions of how to treat your dog (or you) with fish drugs.
Why do these loopholes remain?
- I have no idea. It’s just dumb. They probably just remain because governments haven’t bothered to do anything about it. It might be partly because it’s perceived as a minor contributor to antibiotic misuse (which fish drugs presumably are), but you can’t talk about the importance of such an issue and simultaneously ignore some parts of the problem.
What are the problems with this kind of free access to antibiotics?
- One of the biggest issues is use of antibiotics when they are not needed, which is a common problem. When I was in mixed animal practice, it was far from rare to be called to treat animals that the owner had already treated (unsuccessfully) with his/her own antibiotics. Often the treatment was ineffective because of underdosing or inadequate frequency of administration (both of which will lead to treatment failure and an increased risk of antibiotic resistance). Not uncommonly, though, the antibiotics didn't work because the animal didn't actually have an infectious disease (a steer with a broken leg that was treated for a week with low dose penicillin jumps to mind), meaning antibiotic use just led to unnecessary delays, expense and the potential for resistance, not to mention animal suffering.
Is there any real benefit to having these drugs available over the counter?
- Not that I can see. Sure, people save some money by bypassing veterinary involvement, but how often are treatable diseases improperly treated, resulting in unnecessary animal illness or death, and a loss of more money than a call to the veterinarian would have cost in the first place? Animal welfare aspects need to be considered too.
Some people would put up a fight if these loopholes were closed, including some farmers who like to treat their animals without veterinary assistance (sometimes effectively, sometimes not), stores that sell the drugs and a small subset of people who think they can treat their animals with whatever drug they can track down.
Antibiotics are incredibly important drugs, for both humans and animals. Use of antibiotics in animals can lead to resistance in humans, and vice versa - despite the head-in-the-sand approach of the American Veterinary Medical Association and their infamous position “There is little to no evidence that restricting or eliminating the use of antimicrobials in food-producing animals would improve human health or reduce the risk of antimicrobial resistance to humans.”
Concerns about overuse and misuse of antibiotics lead to calls to restrict antibiotic use in animals. Overuse and misuse are common, in both veterinary and human medicine, and they need to be addressed by both groups. However, antibiotics are needed in veterinary medicine to ensure proper patient care, limit pain and suffering and facilitate production of safe food. What we don’t need is excessive use, inappropriate use or use of antibiotics to make up for bad management practices, which are all things that are more likely in the absence of veterinary oversight.
'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.
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.
There have been various news reports from different parts of North America describing distemper outbreak in raccoons. Distemper is a viral infection caused by canine distemper virus, which is related to the human measles virus (but the canine version can't infect people). A variety of animal species in addition to dogs can get distemper, most notably raccoons.
Distemper outbreaks are not uncommon in raccoons, and one big problem with distemper is that the neurological signs cannot be distinguished from rabies. Yes, there may be some general trends in how a raccoon with distemper behaves that differ from one with rabies, but it’s far from definitive. That creates issues because distemper is of absolutely no human health concern while rabies can be transmitted to humans and is almost invariably fatal.
A Windsor-Essex (Ontario) outbreak of distemper in raccoons highlights some of these issues and the care that must be taken with regard to public communications.
Authorities are “urging the Windsor-Essex public not to worry about a rising number of incidents with strange-acting raccoons: The poor scavengers are suffering from distemper, not rabies.”
- This is bad communication in my opinion. I’d rather see something like authorities are "urging the public the avoid raccoons because of the risk of rabies exposure, but to be aware that a raccoon that is behaving abnormally probably has distemper, not rabies." Telling people not to worry is okay, but making it seem like there's no issue whatsoever is another. No one can say for sure that all of these affected raccoons have distemper, not rabies.
A good statement appears later in the article ”(Executive Director of the Windsor-Essex County Humane Society Melanie) Coulter stressed that although the disease is highly contagious among animals, it can't be passed to humans. But she added that raccoons with distemper are still capable of sudden aggression, especially if they feel cornered. As well, the symptoms of distemper are similar to those associated with rabies -- and the difference can't be determined without lab testing.”
- That’s much better. It highlights the problem and explains that it’s probably not a risk to people, but also makes it clear that you can’t be sure it’s not rabies.
The key thing is avoiding contact with raccoons all of the time, with particular attention to raccoons that are acting abnormally, since they are more likely to have rabies and they can be unpredictable. Some other things to consider:
- Don’t keep raccoons as pets (common but illegal, at least here).
- Don’t encourage raccoons to live around your home.
- Keep pets away from wildlife.
- Ensure dogs (and cats) are vaccinated against rabies and distemper, in case they have an unexpected incident with a raccoon.
It's amazing how one little email comment can make a mess of my week.
Here's the story: I sent an email to a colleague that works for an agency in Ontario. At the bottom of the email, I gave an FYI about an Ontario dog that was found to have antibodies against canine flu, but that wasn't sick. At the time, I didn't realize that my colleague was no longer at the aforementioned agency.
- Astoundingly, instead of cancelling my colleague's email account, the agency had left the account active - and the CEO of the agency reads her emails!
- In this case, not only does the CEO read the email, she forwards it to other people in the agency.
- Not only do the others read it, they create a release that they send out to associates of their agency throughout the province and some other groups... without contacting me to get details, understand the full story or get permission to use the information I provided. Not exactly a good communications strategy.
In an amazingly short period of time, I was contacted by two provincial Ministries about Ontario's canine flu status, since incomplete information was forwarded to them, and veterinary clinics in the province are now asking questions about our "canine flu case" or "canine flu outbreak."
So, to set the record straight (and decrease the number of phone calls I'm getting today):
- We found a dog that had antibodies against canine influenza as part of an outbreak investigation. The outbreak was not caused by canine flu.
- The dog had the same antibody level on two blood samples taken two weeks apart. This is not consistent with disease caused by flu. Rather, it indicates that the dog has been exposed to the virus.
- The fact that the dog has been exposed to the virus is noteworthy. The only other seropositive (i.e. antibody positive) dog that we have seen in Ontario was a greyhound from Florida, and we assumed it was infected in Florida. That was a few years ago, and we haven't seen anything since. Initial information indicates that this dog has not left the province, but I'm working to confirm that before I can be confident that this is evidence that canine flu is present in Ontario.
This is an important topic because if/when canine flu hits a region, it certainly has the potential to cause big outbreaks. The outbreak at a Texas racing facility that I wrote about yesterday is a good example of the bad things that can happen when flu hits a susceptible population. Knowing if the virus is in the area is important for things like vaccination programs and making recommendations for management of respiratory disease cases in veterinary clinics and in the community.
We currently have no evidence of canine flu activity in Ontario, but we are actively looking because we assume that it will make it here sometime, if it's not here now. Identifying it early and communicating that properly are critical control measures for canine flu and other emerging infectious diseases, but there's nothing to worry about at the moment.
As canine influenza continues it's rather gradual, patchwork movement across North America, an outbreak at a greyhound racetrack southeast of Houston highlights some of the concerns about this virus. Canine influenza has been active in the Houston region for some time, causing sporadic infections as well as outbreaks in pet dogs in the community and in veterinary clinics.
Greyhound tracks are a great place for influenza transmission because they have a lot of dogs in close quarters, and racetrack outbreaks can be large and severe. In this outbreak, approximately 100 dogs have been affected so far, with six deaths. It sounds like there are 600-700 dogs on the track, and given how transmissible the virus is, unless they have very tight infection control practices in place to separate groups of dogs (unlikely), it's reasonable to assume that many more dogs will be infected, or have already been infected but weren't recognized because they had mild disease. The ~6% mortality rate is not surprising, as dogs can die from severe influenza or because of bacterial pneumonia that develops afterwards. Higher death rates are talked about, and were features of the early reports of canine flu in Florida, but this lower rate seems to be more typical.
Local Humane Society personnel are rightly warning pet owners to be on the lookout for canine flu. Public awareness is critical, although I'd argue with some of their advice:
"The only protection is the dog flu vaccine."
- Not really. It's part of the infection prevention plan but not the only thing. Vaccination is an effective way to reduce the incidence or severity of disease, but it's not 100%. Vaccination should be considered the last line of defense that comes into play when efforts to avoid the virus have failed. If the dog doesn't get exposed to canine flu, it won't get influenza, regardless of vaccination status. Dog owners need to be aware of high-risk situations and avoid contact with dogs that are or have recently been sick. That being said, in an area where canine flu is active, vaccination is a good idea, since you can never completely guarantee your dog won't be exposed to the virus if it's exposed to other dogs.
"Dog owners were warned if they noticed any flu-like symptoms in their dog to take them to a vet immediately for antibiotics and the vaccine and not to take their dog to the park or doggie daycare."
- I agree with the last part. If your dog is sick, keep it away from areas where other dogs mingle while it's sick and for about 10 days after it gets better. So, if that's the case, why take all potentially sick animals into the vet right away? It might just result in exposure of other dogs to the virus. If you have influenza and you're not very sick or at high risk for complications, the recommendation isn't to immediately go to the doctor. It's to rest and stay away from other people. The same applies for dogs.
- Calling a veterinarian to see whether the dog should be examined makes sense. This also helps ensure that if the dog does go to the clinic, it can be handled properly. By that, I mean instead of showing up, checking in at the front desk and lingering in the waiting room with other dogs for a while, a dog with suspected flu should be admitted directly into isolation or an exam room. This can be done by calling the front desk on arrival or by checking in without the dog, so that the dog can be taken directly to a contained area to avoid other dogs.
- Antibiotics are rarely needed. Antibiotics don't kill influenza virus, so they are indicated only if there is evidence (or very high risk) of secondary bacterial disease, which doesn't happen in most cases. We don't want every coughing dog on antibiotics, since few need them.
Max, a 12-year-old Chihuahua from Greenfield, New Jersey, was euthanized recently after he was exposed to rabies. While far from unusual, the case highlights the ongoing risk of rabies exposure as well as issues with understanding of rabies guidelines and communication.
Max was attacked by a rabid raccoon - an ever-present risk for animals that go outside (or get outside) in many regions. Animal control was called and the raccoon was caught. It was euthanized and rabies was confirmed, indicating that Max was very likely exposed to the virus.
Here's where things seem to get strange. The paper reports:
"Once exposed to a rabid animal, a six-month quarantine is required for the exposed animal, even those animals that have been inoculated with a rabies vaccine."
- Not really. In Canada, standard guidelines are for a 6 month strict quarantine for dogs (and cats) that are not properly vaccinated, but only a 45 day observation period is required for vaccinated animals. I don't know if in this jurisdiction they made up their own different rules, whether someone doesn't know what's supposed to be done or whether it's poor reporting, but it's a concern because it can be a difference between life and death... not necessarily from rabies, but from the quarantine requirements alone. People are often unwilling to undertake a strict 6 month quarantine and choose euthanasia (as was the case here), while the 45 day observation period is much more acceptable.
The attending veterinarian stated "Because of the way it was exposed and because of the positive, I think there was a really good chance this dog was going to get rabies".
- It's certainly possible, and nowhere does it say whether Max was properly vaccinated. However, there's a reason we vaccinate. It's a highly effective vaccine and we're trying to prevent disease. Nothing's 100%, but with proper vaccination, the risk of rabies is greatly reduced.
It's also stated that "due to the nature of rabies, until behavioral changes occur, the animal is not infectious".
- While this doesn't have anything to do with Max's situation, it's not true. Animals can shed the virus for a short period before they show signs of illness. That's the reason there is supposed to be a 10 day quarantine period after a dog bites someone - to see if the dog develops signs of rabies (which would have major implications for the person who was bitten).
Curiously, the article ends with a reminder to vaccinate pets, which seems kind of strange if their assumptions are that an exposed animal will get sick irrespective of vaccination status and that vaccination will have no impact on what happens to an animal after exposure.
However, despite the miscommunication, the take-home message emphasizing the need for vaccination should be heeded. As well, people making decisions about what to do after rabies exposure should make sure they do so based on the best evidence that's available, namely the Compendium of Animal Rabies Prevention and Control.
An interesting and frankly somewhat scary report in an upcoming issue of Veterinary Microbiology (Clegg et al 2012) provides further information suggesting that cats might be a source of canine parvovirus infection. This potentially fatal infection, which typically affects young unvaccinated (or inadequately vaccinated) puppies, is a major problem, and outbreaks occur (not uncommonly) in some high-risk populations like shelters.
In the 1970s, a new form of canine parvovirus, CPV-2, emerged and rapidly spread worldwide. That predates my veterinary career but I've heard stories of clinics where you couldn't turn a corner without stepping on a dog that was hospitalized for treatment of parvo, since it was a new disease and vaccines were not yet available. CPV-2 was shown to be able to grow in cat cells in the lab, but not in live cats, so it was generally assumed that dogs had CPV and cats had their own closely related virus, feline panleukopenia virus (FPLV). However, new variants of CPV-2 have emerged over time, and these seem to have a greater ability to infect cat cells in the lab, and disease caused by these strains has been reported in cats both experimentally and in limited real-world situations. However, it was still considered an uncommon event and the role of cats in parvovirus infection of dogs was largely thought to be inconsequential.
Or maybe not.
In this new study, researchers collected fecal samples from 50 cats in a cat-only shelter, and 180 samples from 74 cats at a shelter than housed both dogs and cats. Canine parvovirus shedding was identified in 33% of cats from the cat shelter and 34% of samples from the dog/cat shelter. A concern with a study like this is cross-reaction of tests for CPV and FPLV, but they went a few steps further to confirm that the virus was indeed CPV, not its feline relative. They also showed they could grow the CPV from fecal samples in cells in the lab, which means they were detecting live virus in the animals, not just dead viral bits working their way through the cats' intestinal tracts.
The results are interesting and concerning, since they showed that a pretty large percentage of cats in some situations could be shedding live CPV, making them a potential source of infection for dogs (and possibly other cats).
What makes this even more concerning is the duration of shedding that they identified when they collected samples from the dog/cat shelter over time: cats shed the virus for up to 6 weeks, despite appearing healthy.
This raises concerns about the potential role of cats in the spread of CPV. Cats and dogs don't tend to mix much in parks or outside, but CPV is a very tough virus that can survive for a long period of time in the environment. It's certainly plausible that cats could be depositing CPV-laden feces in the outdoor environment, and since the virus can survive the outdoor exposure and some dogs are notorious poop-eaters, it's a route of transmission that can't be dismissed. Cross-contamination within shelters is also a concern.
The true role of cats in canine parvovirus infection isn't known and it's probably quite limited compared to dog-to-dog spread. However, this study shows that we at least need to be thinking about it and considering cats when dealing with parvovirus problems in shelters and households.
Some things to think about:
- Young puppies should be kept away from cats, especially strays and cats from shelters, until they are properly vaccinated.
- Parvo is one more reason to have good physical and procedural separation between cats and dogs in shelters.
- If a parvo outbreak in underway in a facility, prevention of potential cross-contamination from cats is required.
- If a cat has been in contact with a dog with parvo, it should probably be considered potentially infectious and kept away from susceptible dogs for at least a few weeks.
- Canine parvovirus vaccination is highly effective in dogs. If a dog is properly vaccinated, the risk from cats (or other dogs for that matter) is minimal.
Kennel cough, also (and more properly) referred to as canine infectious respiratory disease complex (CIRDC), has been in the news lately. This condition is a syndrome, not a specific disease, being potentially caused by a range of bacteria, viruses and Mycoplasma, including canine parainfluenza virus, canine influenza virus, canine respiratory herpesvirus, canine adenovirus, distemper virus, Bordetella bronchiseptica and Streptococcus zooepidemicus. Regardless of the cause, it's still a highly infectious disease characterized by a hacking cough. Serious illness, including deaths, can occur but is uncommon.
Here are a couple of kennel cough issues have hit the press lately:
- Mandatory kennel cough vaccination is now required for dogs competing in the Iditarod Trail Sled Dog Race. It's easy to see how this disease is a concern in these sled dogs, given the stress and rigours of competing and the mixing of many dogs from different areas. Kennel cough vaccination doesn't prevent all cases, since it only protects against Bordetella bronchiseptica +/- parainfluenza virus, but it's a useful infection control tool in high risk populations. The requirement has been implemented in part due to cases of kennel cough that were encountered in the 2011 race, along with the publicity that was generated (including the attention of PETA).
- In Rocklin, California, a dog park was closed for two days because of a kennel cough outbreak. It seems the closure was in response to the diagnosis of kennel cough in two dogs, and it's an unusual move given the apparently low number of cases. The issue isn't the park environment itself being biohazardous - rather, the park provides an opportunity for dog-dog transmission. Given that, it's a questionable control measures since it's unlikely that people will keep their dogs at home. Rather, they'll probably just go to another park, where the same risks will be present. It's a bit like the debate around school closures with pandemic influenza. On the surface, it seems like a good idea, since kids won't pass around flu at school. However, in reality, what happens is kids congregate at the mall and other places if schools are closed, so it just moves the site of transmission somewhere else and probably doesn't have any net benefit. Here, a better response would probably be an educational campaign to get people to keep sick dogs at home, have people keep their dog away from other dogs at the park and encourage vaccination of high risk dogs (which would include those that go to a park and interact with other dogs).
- A kennel cough outbreak was reported in Bozeman, Montana, with veterinarians asking owners to be on the lookout for disease. Local veterinarians reported a spike in the number of cases, with one clinic reporting around 20 cases in the past month, which is a pretty remarkable number for your average vet clinic.
- And locally... nothing specific, but I keep getting reports of clusters of respiratory disease in dogs. We often don't get a chance to investigate small clusters to figure out the cause, since information often gets to me after the fact, but it's a recurrent problem in Ontario. Most of the reports are rather poorly defined clusters of sick dogs, with occasional severe outbreaks involving fatalities (including one I'm dealing with at the moment).
Rabies is pretty rare in horses in North America, with only 37 reported cases in the US in 2010 and 1 in Canada in 2011 (the latest years for which data are available). So, finding two apparently unrelated cases of rabies in horses in the same area in the same month is pretty unusual and concerning. Yet, that's what's happened in Tennessee, where rabid horses were identified in both Rutherford and Marshall counties in January.
Little information is available about the cases, but both were identified as having the skunk rabies virus variant. That doesn't necessarily mean they were infected by skunks (since other species can be infected by this virus variant) but it is suggestive, and indicates that rabies must be active in the skunk population in that region.
Regardless of the source, these cases are a reminder of why rabies vaccination of horses is important, and why rabies vaccination is considered a "core" equine vaccine by the American Association of Equine Practitioners. Rabies is invariably fatal in horses and it's also a major public health risk. While I've been unable to find confirmed cases of horse-to-human rabies transmission, it's a possibility, and additionally, rabid horses have killed people because of their unpredictable and aggressive behaviour.
Vaccination is cheap insurance against rabies - it's never a 100% guarantee, but it's a whole lot better than without vaccination.
A Prince George, British Columbia veterinarian is warning other veterinarians and horse owners about West Nile in the province. Little information is available at this point, but the warning is in response to a diagnosis of West Nile infection in a horse from the area. The report calls it a "deadly disease" but it would be more appropriate to call it a "potentially deadly disease," since most horses that are exposed don't get sick, and many sick horses recover. I don't want to downplay the seriousness of West Nile, but it's important to keep it in perspective and make people panic.
The BC CDC has an ongoing West Nile surveillance program because of the obvious concern as this virus has worked its way across North America over the last decade. While it's taken it's time getting to BC, West Nile virus has been identified in the province, and only time will tell whether it becomes a serious health concern for horses or people. The latest update of the BC CDC surveillance data indicates one positive horse, but no positive humans (of 415 tested) or mosquito pools (2282 tested). The one equine case that was documented was from Central Okanagan. The horse had clinical signs consistent with infection, although the severity and outcome are not reported.
It's unclear to me whether this Prince George case is something that's happened just recently or whether the horse was sick. It's pretty late in the year for a mosquito-borne virus, but not impossible in some areas.
Does this report mean that horse owners in BC should be concerned? Maybe. "Aware" might be a better term.
Horse owners and veterinarians always need to be aware of the infectious disease risks in their area, and areas to where a given horse may travel. Keeping apprised of ongoing West Nile virus surveillance can help determine the likelihood of exposure, but that doesn't mean you can wait until there's a case next door before you do anything. (Someone has to have the first case in an area, and you don't want that to be you.)
Whether or not to vaccinate against this virus depends on the likelihood of exposure and risk aversity. Available vaccines are rather safe and effective (not 100% on either account, like any vaccine, but quite good overall), and vaccination decisions should be made based on a well-reasoned discussion between veterinarian and owner, considering a variety of factors such as where the virus has been found and how much risk everyone is willing to take.
The news report has a quote recommending vaccination in the spring. That's the typical time people vaccinate against mosquito borne diseases, but that's not my recommendation. For me, the goal is to vaccinate so that peak immunity is present at the time when exposure is most likely. West Nile virus is classically a late summer/fall disease, based on mosquito types and their biting patterns. For that reason, I like to see horses vaccinated a little later in the year - closer to the high risk period. Again, it's important to know disease trends in each region to make the most informed decision.
So, horse owners in BC should be aware but not panic. A good discussion about vaccination and about general mosquito avoidance practices should be the first thing that happens.
Marion County (Florida) public health personnel recently issued a rabies alert after a horse in the area tested positive for the virus. It’s a standard alert, emphasizing avoiding contact with wildlife, reducing things that attract wildlife to houses (e.g. accessible pet food or garbage) and recommending vaccination. Interestingly, while this alert was prompted by a case of rabies in a horse, it only mentions vaccination of dogs, cats and ferrets. That may have been because it was an off-the-shelf alert, not really tailored to this situation, but it shows how horses can be overlooked when it comes to rabies.
Fortunately, rabies is a rare disease in horses. In 2010, there were 37 reported cases of equine rabies in the US and only one in Canada (two Canadian cases have been identified so far this year). That’s a very low rate, especially considering the number of horses out there, but it’s still more cases than there should be for a very serious yet highly preventable disease.
Unfortunately, rarity sometimes breeds complacency, so despite the fact that rabies is invariably fatal in horses and rabid horses pose a risk to people, vaccination of horses is often overlooked. While rabies is rare in horses, rabies vaccination shouldn’t be rare. Every horse in a rabies endemic region (or that might be traveling to such a region) should be vaccinated against rabies. It’s cheap insurance against a very dangerous and deadly disease.
A parvovirus outbreak has been identified at the Occupy San Francisco camp, with at least three dogs affected by the highly contagious and potentially very serious viral disease. The San Francisco SPCA has visited the camp and their temporary clinic was attended by "dozens" of dog owners (indicating lots of dogs at the camp). This is a nice proactive step to help contain the parvo outbreak and hopefully reduce the risk of transmission of various other infectious diseases amongst the animals. Some people appreciated the help. Others (probably the subset that complains about everything) accused the SPCA of spreading bad publicity to help shut down the camp. (I guess they'd rather have good press than healthy dogs.)
In many ways, it's not too surprising. "Occupy" camps are just asking for infectious disease outbreaks, more so in people, but the same risk factors are there for dogs. Whenever you mix together lots of different individuals from different sources, put them in close and prolonged contact and have hygiene challenges, you set the scene for infectious diseases. From a canine parvovirus aspect, heavy fecal contamination from dogs defecating in a small, concentrated area and unvaccinated dogs feed the fire even more. (I don't know for sure that the affected dogs were un- or incompletely-vaccinated, however given the excellent effectiveness of parvovirus vaccines, it's highly likely that sick dogs were not adequately vaccinated.)
Parvo isn't the only infectious disease problem at the camp. Kennel cough (now known as canine infectious respiratory disease complex, CIRDC) has also been identified. This syndrome, caused by a mix of bacteria, viruses and Mycoplasma, has greater potential to spread widely because some of these bugs are highly contagious and vaccination coverage in the population will be lower than for parvo. A large-scale kennel cough outbreak is quite likely if there is kennel cough activity at the camp.
What can you do to reduce the risk, whether it's while "occupying" or during your daily activities?
- Have your puppy vaccinated as per your veterinarian's recommendations.
- Don't take unvaccinated puppies to areas where there will be lots of other dogs. "Unvaccinated" includes puppies who have not had their full initial series of vaccines.
- If your dog is sick, don't take it out in the public, especially to places where other dogs will be present.
- If your dog gets sick during a public event, take it away promptly to reduce the risk of it infecting other dogs.
- Don't let healthy skepticism grow to paranoia, and don't let political squabbles interfere with proper healthcare... both human and veterinary.
Canine influenza continues to be a problem in some areas of Texas, most notably in the Austin area. A recent news report indicates 30 confirmed cases and 70 suspected H3N8 canine influenza cases since September.
It's hard to say what the scope of the problem really is, but something's definitely happening. Getting good data about infectious diseases of companion animals is difficult because there is no central surveillance program and government animal health agencies tend to have little interest in non-food animals. Data tend to be assembled by word of mouth, which can lead to either over- or under-estimation of the problem. As highlighted by the number of "suspected" cases, lack of diagnostic testing is also an issue. Since dog owners have to pay for the testing themselves and since, for influenza, test results rarely change what's done for initial treatment of the dog, many people are reluctant to have the tests done. That leaves us with large numbers of unconfirmed cases, as is this situation. When there is documented flu activity in the area, a suspected case could quite likely be influenza. The bigger problem is in areas where flu is not common or hasn't been found, because canine flu looks no different than several other causes of respiratory disease, and knowing whether it's really flu is important for making vaccination decisions, as well as implementing certain infection control measures.
Avoiding exposure to canine flu is tough in areas where flu is active, just like it is for people when human flu is circulating. One of the big problems is that infected dogs start shedding the influenza virus from their respiratory tract before they get sick. Therefore, staying away from sick dogs and keeping your dog at home if it has signs of disease can't completely prevent exposure. However, these steps are still very important as they can help reduce the risk. Vaccination is another measure to reduce the risk. Vaccination is not 100% protective but it is an important part of influenza control in dogs that might be exposed to the virus.
Veterinarians at Michigan State University's College of Veterinary Medicine are warning of an upswing in leptospirosis in dogs in the Detroit area. More than 20 cases of leptospirosis have been reported in dogs in the Detroit area, and it's likely that many more unreported cases have occurred. Leptospirosis, a bacterial infection, can cause very serious disease, including potentially fatal renal failure. It can be vague and hard to diagnosis if people aren't thinking about the disease. The most commonly identified problem is kidney disease, and early diagnosis and treatment is critical for successful treatment.
The Leptospira bacterium can survive well in the environment, particularly in moist conditions, and dogs are often exposed through wet environmental areas that have been contaminated with leptospires from the urine of infected wildlife. The strain that has predominated in the latest Michigan cases is Leptospira Icterohemorrhagiae, a type most often associated with rats.
Prevention of leptospirosis involves avoiding exposure to the bacterium as much as possible (largely through avoiding contact with wet areas where lepto cases have been identified) and vaccination. Vaccines are available for dogs and they can reduce the incidence and severity of disease caused by four different lepto types, including Icterohemorrhagiae. Vaccination should be considered in dogs in regions where lepto cases are identified and in dogs at increased risk of exposure based on lifestyle and travel.
While it's not really an occasion to celebrate, September 28 was World Rabies Day. Rabies has been a problem for millennia, and it's not going away any time soon. This viral disease, which is almost invariably fatal, kills 50 000 - 70 000 people per year. Some countries have astounding rates of rabies cases, such as India where ~20 000 people die of the disease every year. Internationally, most human rabies infections are caused by dogs, but wildlife are the main source in some regions (such as Canada and the US) . Basically all rabies infections are preventable with proper access to good medical care and rabies post-exposure prophylaxis, but sadly the thousands of people who die do not receive treatment.
Is rabies controllable? Yes. With measures to reduce rabies in wild and stray animals, pet vaccination, public education measures, good access to medical care, adequate rabies vaccine supplies and adequately trained healthcare personnel, the incidence of rabies can be dramatically decreased. However, these measures require time, money, effort and political will, and those are limitations in some areas.
Can rabies be eradicated? That's a tough question. Eradicating a disease that can be found in many wild animal species internationally is extremely difficult. It's hard to envision complete eradication of this virus, as was done for smallpox (a human-only disease) and rinderpest (a cattle-only disease). Both those diseases had the advantage of only being found in one species, making control and eradication much more feasible. However, while we might not be able to eradicate rabies, it's certain that tens of thousands of lives could be saved every year with good rabies control programs.
More information about rabies can be found in on the Worms & Germs Resource page.
A recent case of canine rabies in France showed yet again the risks posed by illegal importation of animals. This case is somewhat unusual since it seems to involve ignorance of the rules and lax enforcement, compared to rampant animal smuggling, but the end result was the same.
The animal in question was a puppy that was brought to France by a family that had been vacationing in Morocco. They found the puppy on July 11 and returned to France on July 31. European Union regulations require that imported dogs be vaccinated against rabies and microchipped. Neither was done to this puppy, and it was in fact too young to vaccinate against rabies according to standard protocols. The family traveled back to France by ferry and car, and either met no customs officials or at least no officials who asked any questions about the puppy.
They day after they returned to France, the puppy started to exhibit behavioural changes and progressive sleepiness, with subsequent development of aggression. Five days later, it was taken to a veterinarian and it died the next day. Rabies was confirmed a few days later, and testing of the virus strain indicated that it was of the Africa-1 lineage and closely related to strains previously isolated in Morocco.
An investigation into possible rabies exposure ensued. Typically, it is assumed that animals can be infectious for up to 10 days prior to showing signs of rabies. Often, this is extended by several days for added confidence and because it's not always possible to determine exactly when the earliest, mildest signs might have developed. In this case, they considered the period that rabies could have been transmitted to be from July 18 until the puppy's death.
Multiple people had close contact with the puppy. Three family members had been bitten, a clear indication for post-exposure treatment. One other person (a friend of the family, it appears) was also bitten and received treatment. Another person reported being licked on non-intact skin (i.e. an area of skin with a cut, abrasion or other break in the normal barrier) and was also treated. The attending veterinarian, who had been previously vaccinated, received two booster shots.
This isn't the first time that rabies has made its way from Morocco to France, and it's concerning that it was so easy for it to happen. Nine rabid dogs have been illegally imported to France from Morocco since 2001. In 2008, one such dog subsequently transmitted rabies to several other dogs, resulting in France losing its rabies-free status until February 2010. It's not surprising that no questions were asked of the family traveling from Spain to France because of the open nature of borders between EU countries, but the ability to enter Spain from Morocco with no flags being raised is a concern. Hopefully there's an investigation into how this puppy was able to get into Europe so easily and how to reduce the chances of this happening again.
The mosquito-borne diseases eastern equine encephalitis (EEE) and West Nile (WNV) continue to rear their ugly heads in the northeast as we get further into the late summer season during which they are most common.
On August 13 there was an unconfirmed report of a case of West Nile in a horse at Woodbine Racetrack, just north of Toronto. No additional details have been forthcoming regarding the severity of the infection or the status of the horse, if WNV infection has in fact been diagnosed. Nonetheless, the Ontario HBPA is urging horse owners to ensure the vaccination status of their animals for West Nile is up-to-date. Unfortunately, if horses are not already vaccinated at this point, even vaccinating them immediately may still leave them susceptible to virus for the next few weeks until they are able to fully respond to the vaccine. This news follows close on the heels of news reports regarding increased numbers of WNV-positive mosquito pools in various regions north of Toronto, and thus is not altogether surprising.
The first case of West Nile in a human in New Jersey was recently diagnosed in a man from Mercer County. Again, no additional details about the severity of the infection or the man's condition are available, but the public is once again being urged to protect themselves against mosquitoes by wearing long sleeves and pants, using insect repellant, and eliminating standing water in which mosquitoes may breed on their property. Elsewhere the death on August 14 of a four-year-old girl in New York from infection with EEE has been reported. She is the fifth person in New York state to die from the disease in 40 years. The girl first began showing signs of infection earlier this month, but the diagnosis of EEE infection was only reached last week. EEE has a high mortality rate in humans as well as horses. Just as infection in animals can act as sentinel indicators for disease risk in humans, these human cases indicate that WNV and EEE are active in these respective areas, and humans and horses alike are at risk of infection. Mosquito avoidance can help protect both, and in addition timely vaccination of horses can help decrease the risk of disease.
Following on the heels of the beginning of the start eastern equine encephalitis (EEE) season, warnings are going out about another mosquito-borne disease in parts of North America, West Nile virus (WNV) encephalitis. While mosquitoes have been swarming around here for months, WNV only becomes a real concern in southwestern Ontario starting in mid-to-late August. This time of year, the virus starts increasing in the mosquito population, and the types of mosquitoes that bite both birds and mammals (and therefore act as a bridge between the bird reservoirs and susceptible mammals like horses and people) become more common and more active.
Reminders about WNV have been issued in Ontario over the past few days because of increasing numbers of mosquito pools testing positive for the virus. Mosquito pools are groups of mosquitoes that are caught and tested together to see if the virus is present. The more pools that are positive, the more mosquitoes that are positive and the greater the WNV activity in the area.
People are being reminded to take measures to reduce mosquito breeding grounds on their property, which mainly means getting rid of standing water. Avoiding mosquito bites through basic measures, such as staying away from mosquito-infested areas (particularly at dawn and dusk), wearing light coloured clothing with long sleeves and long pants, using insect repellent containing DEET and making sure windows have intact screens, is also emphasized.
Recommendations are similar for horse owners; reduce mosquito breeding sites and reduce mosquito exposure of your horses (although this can be easier said than done). Vaccinating horses against WNV should also be considered. The dramatic decline of WNV infection in both people and horses after it first emerged back in 2001/2002 was quite impressive, and WNV hasn't ended up being the major problem it could have been. In 2011, there was only 1 confirmed case in a horse in Ontario. Presumably, there were more undiagnosed cases but this shows how the disease has leveled off to be an uncommon but still present issue.
Despite disease due to WNV being rare in Ontario (remember that the virus itself is not rare because the mosquito pools are still testing positive), WNV shouldn't be ignored because it still has the potential to cause severe illness in horses and people. When deciding whether or not to vaccinate your horse, consider carefully the risk of mosquito exposure, WNV activity in your local area, WNV history in horses and people in the area and your own level of risk aversion.
A Chapel Hill, North Carolina woman is suing Orange County in response to quarantine of her dog because of possible rabies exposure. This lawsuit highlights some of the inconsistencies in application of current rules, along with some misunderstandings.
In February, her dog Russell was barking at something under her deck, and that something ended up being a raccoon with rabies. There's no evidence of a fight or contact, but it can't be ruled out. Because of this, the dog was considered potentially exposed. Russell was overdue for his rabies booster, so a strict six-month quarantine was required, and the county required that this be done at an approved facility, not in the home. (The alternative option was euthanasia.)
- The lawsuit is based on the inconsistent application of the rules by various counties. The owner is seeking permission to quarantine the dog at home. This is allowed in many regions, provided there is confidence that the owner is responsible enough to properly quarantine the animal.
- It's a reasonable argument that's based on subjective and variable application of rabies guidelines. Certainly, formal quarantine in a facility offers more containment. The question is when household quarantine is appropriate, in terms of the animal's risk of exposure and the ability of the household to properly quarantine the animal.
Some other highlights:
Russell was overdue for his rabies vaccine by 46 days.
- Dogs don't immediately go from protected to unprotected. Certainly, we want animals to be up-to-date on their vaccines, but some thought needs to go into dealing with potentially exposed overdue animals. The NASPHV Rabies Compendium states "Animals overdue for a booster vaccination need to be evaluated on a case-by-case basis (e.g. severity of exposure, time elapsed since last vaccination, number of prior vaccinations, current health status, local rabies epidemiology)."
- Knowing the age of the dog and the number of previous vaccines would help, but the news article reports vaccinations (plural), suggesting that he's been vaccinated more than once in the past. In a dog with a relatively low index of exposure that was only overdue by 46 days, it would seem reasonable to consider it protected and treat it as vaccinated (although it's hard to say this definitively based on a news report that doesn't give the whole story). It's a critical point because considering the dog up-to-date would only result in a 45 day observation period as opposed to a strict six-month quarantine.
The owner's veterinarian stated that research shows that an animal that is vaccinated regularly is protected for many years, if not a lifetime.
- Yes and no. Vaccination is quite effective and in most animals probably confers long-lasting protection. However, I'm not aware of research that really shows this. This isn't a disease where we have good research data about duration of effect of vaccination. I suspect that most dogs that have been regularly vaccinated are well protected. Most does not equal all, and with a disease like rabies, you have to be quite sure.
A rabies antibody titre was measured. This is a blood test indicating the level of anti-rabies antibodies. The veterinarian indicated that the titre showed Russell is currently protected from contracting rabies.
- Unfortunately, no. TItres tell you antibody levels, but we don't have good data about what is actually protective. Higher is better, but we can't say a certain number is absolutely protective. Back to the NASPHV guidelines: "Titers do not directly correlate with protection because other immunologic factors also play a role in preventing rabies, and our abilities to measure and interpret those other factors are not well developed. Therefore, evidence of circulating rabies virus antibodies should not be used as a substitute for current vaccination in managing rabies exposures or determining the need for booster vaccinations in animals". That statement was echoed by North Carolina's state public health veterinarian, Dr. Carl WIlliams.
This is a tough situation. In many circumstances, home quarantine is a reasonable option. It's easier on everyone involved, by not separating the dog from the household. It's also less expensive. However, it inherently comes with some degree of risk to the household and the community. It's only a reasonable option when it's certain that people will take "strict quarantine" seriously, and truly quarantine the animal. That's hard to assess, and regulatory bodies are presumably afraid of assuming liability should they allow someone to quarantine an animal at home and something bad happens (e.g. it develops rabies and exposes people in the household, the owners take it outside where it encounters other animals or people, it escapes...). Determining whether someone can and will properly quarantine an animal isn't easy, and those issues presumably lead some people to err on the side of caution, and require formal quarantine at an approved facility.
The easiest way to avoid all this: Ensure your pets are properly vaccinated.
An important concept when dealing with infectious diseases is consideration of the risk that an animal has been, or will be, exposed to a particular microorganism. Some diseases vary greatly geographically, and something that's very important in one region may be rare or non-existent in another. Good veterinarians are aware of disease trends in their area and make informed decisions about vaccination and anti-parasitic treatments based on what's happening in the area. They also know which diseases are common and which are rare or non-existent.
But that only works if the pets stay in their "home" area. Traveling with pets can result in exposure to various infectious diseases they wouldn't normally encounter. If a veterinarian doesn't know a pet travels, they can't make proper recommendations for preventive medicine.
Additionally, travel history can be very important when evaluating a sick animal, since there may be diseases that need to be considered in a traveling pet that wouldn't be an issue with a local pet. However, it's easy to overlook or forget about travel history. Pet owners need to tell their veterinarians about "recent" travel with their pets. What does recent mean? It's hard to say. For some diseases, exposure within the past few days is all that's important. For others, it may be weeks or months. So, if you have a sick pet and have traveled any time in the past year with it, it's good to mention that to your veterinarian. It may have nothing to do with the current illness, but it never hurts to let them know anyway. In some situations, it may be the critical piece of information needed to trigger thinking about a specific disease.
Some examples of diseases that may be travel-related (at least to dogs in most parts of Ontario):
- Blastomycosis, a fungal disease, tends to occur predominantly in specific areas. It's not too common elsewhere, but travel to high-risk areas puts blasto on the list of possibilities in certain cases.
- Around here, there's no indication for heartworm preventive treatment during cold winter months, but that changes if the pet goes to areas where mosquitoes hang around all year.
- Some tickborne diseases have very specific ranges that correspond to their primary hosts and certain vector species (such as birds). In Ontario, ticks are currently quite geographically focused and many dogs have little risk of exposure. Travel to one of the tick hotbed areas changes that, and means that certain tickborne diseases need to be considered.
- Canine influenza currently seems like a non-entity in Ontario. We're still looking for it but haven't found it. It is present in some places in the US, and at times, is a big problem. Travel to a place experiencing a canine flu outbreak would be a good indication to consider canine flu vaccination.
What to do?
- If you travel with your pet, part of your pre-travel checklist should be an appointment with your veterinarian to go over anything that needs to be done, be it vaccination, deworming, flea control, heartworm preventive or anything else. (It's also a good time to make sure there's nothing else going on with your pet, because you don't want a pet health crisis en route.)
- If your pet gets sick and has traveled, make sure your veterinarian knows where you went and when.
- If you travel regularly, even if it's not long distances, it's good to discuss it with your veterinarian to see if anything is required for your pet. Even if you just go a couple of hours away to a cottage regularly during the summer, you may be exposing your pet to something different.
Rabies in a lamb and cow at a petting zoo (or more accurately, in a communal group of hobby animals) has been reported in Israel. This follows identification of rabies in another lamb from the same group last week. Little is reported about possible sources of infection of these animals, at Kibbutz Neve Eitan, or how widespread human exposure may have been. It's a concern given the serious nature of rabies and the possibility that there was largely uncontrolled contact with the public, which complicates tracing of potential exposures. Given the state of rabies in Israel, the canine rabies variant is most likely the cause.
Presumably, public health and Kibbutz personnel are contacting people in the area to determine who may have had contact with the animals. Casual contact is not a risk for rabies transmission - it is only transmitted through contact of an open wound or mucous membrane (e.g. nose, mouth, eyes) with saliva from an infected animal. The risk of transmission to humans from contact with species like sheep and cattle is pretty low, however the tendency of young animals to suck on things and the fact that people often let them suck on a fingers when playing with them raises the potential for exposure. Anyone identified as having high-risk contact needs post-exposure treatment, consisting of a shot of anti-rabies antibodies and a series of four vaccines over the course of a month (unless they have been previously vaccinated against rabies, in which case they just need two booster shots).
Any animals involved in public displays, petting zoos or other events where there may be contact with the public should be vaccinated against rabies. That's particularly true in areas such as Israel, where rabies is endemic.
Leptospirosis is disease caused by several types of Leptospira bacteria. It's often called a re-emerging disease in dogs, because the incidence has been increasing over the past couple of decades in many areas. While the overall number of infections is limited, when it does occur lepto can cause serious disease, including kidney failure. It's also a zoonotic disease: lepto can be transmitted from sick dogs to the people who handle them. Infected animals shed the bacteria in their urine, and when the urine comes in contact with broken skin or mucous membranes (mouth, eyes, nose), transmission of infection can result.
Canine vaccines against lepto are available. In the past, lepto vaccination hasn't been all that popular because the vaccines tended to have a higher rate of side effects compared to most vaccines, and the types of lepto that the vaccines targeted were often not the most important types causing disease. This has changed more recently as newer vaccines have become available. These vaccines seem to have low rates of adverse effects and provide protection against the four types of lepto that tend to be the most important. These vaccines have also been shown in research studies to protect against disease and to reduce shedding of the lepto bacterium in urine (thereby decreasing the risk of transmission to other animals or people).
Lepto is not among the "core" vaccines that groups say all dogs should have. That's because the risk of lepto exposure varies greatly between regions and dogs. The key thing to consider when deciding whether or not to vaccinate is what each individual dog's risk of exposure is. The main reservoir of lepto is wildlife such as rats and raccoons. If infected wildlife are in the area, they may be peeing out lepto and contaminating the environment, particularly any type of standing water (lepto loves to live in warm, wet environments).
In the past, much of the concern has been focused on dogs that go out and swim in streams or ponds. The "poster child" for lepto has typically been the Labrador Retriever that goes out gallivanting in the bush, but that may be changing too. When you consider where wildlife such as rats and raccoons live and how high the wildlife infection rates can be, remember that these pests can be present in urban areas in incredibly large numbers. Living in a city does not make a dog safe from exposure to lepto. In fact some urban areas, with large numbers of wildlife crowded into high-traffic areas like parks, are probably higher risk than rural areas.
Deciding on vaccinating requires an understanding of how common lepto is in the area and whether there is a risk of exposure for the individual animal. This is a disease for which a veterinarian's understanding of disease patterns in an area (including any specific areas that be particularly high risk) and the types of possible exposure of the dog play a big role. There's no "one size fits all" recommendation for lepto vaccination.
Kinkajous are strange little mammals from the Procyonidae family - the same family to which raccoons belong. Kinkajous are native to Central and South America and are occasionally kept as pets, but they don't make great pets because they are strictly nocturnal, can be cranky when woken during the day, and can sometimes be aggressive. Regardless, there is a niche pet trade, particularly in the US.
A recent report in Morbidity and Mortality Weekly Report describes detection of Baylisascaris procyonis (the raccoon roundworm) in pet kinkajous in the US, including:
- A 10-week-old kinkajou in Tennessee in which Baylisascaris procyonis was found during a routine fecal examination.
- Detection of Baylisascaris eggs from soil samples under the cages of a kinkajou breeder in Florida (the breeder from which the Tennessee animal was obtained).
- An unrelated case (11 years earlier) in which adult Baylisascaris worms were found in the intestinal tract of two adult kinkajous that died of other causes.
No human infections (i.e. cases of larval migrans) were linked to infected kinkiajous.
Baylisascaris is a parasite that's extremely common in raccoons, rare (but concerning and sometimes over-hyped) in dogs, and an extremely rare cause of disease in people. While rare in humans, it still gets a lot of attention because when disease does occur, it can cause serious neurological damage, typically in children. The damage is caused by migration of parasite larvae through the body, and through the brain. This can occur after someone swallows infective parasite eggs, which then hatch in the intestinal tract and then embark on their journey through the body.
It's unclear whether Baylisascaris is a common problem in kinkajous (like it is in raccoons) or a rare finding (like it is in dogs), since this report only describes the parasite in a small number of animals, and no larger studies of intestinal parasites in kinkajous have been reported. It would be useful to know whether kinkajous are true reservoirs of this parasite (and therefore whether we should consider all kinkajous to be carriers) or whether infection is just an unusual finding.
Overall, the public health risk is likely limited.
- There aren't that many pet kinkajous around, as far as I know.
- While Baylisascaris is nothing to dismiss, to get infected, a person still has to eat infective eggs from feces. The likelihood of transmission from a pet to a person is therefore low if good basic hygiene measures are used.
- The parasite eggs are not immediately infectious. They have to sit around in the environment before they are infectious, usually for 2-4 weeks. Therefore, prompt removal of feces and careful attention to basic practices like hand hygiene should greatly reduce the risk of transmission.
- Routine testing and deworming of pet kinkajous should reduce the risk even further.
What does this mean for pet kinkajou owners? Not a lot beyond what would normally be recommended. Pet kinkajous should have good veterinary care and regular fecal examinations. Regular deworming should be discussed with the attending veterinarian, and good hygiene practices should be used to avoid contact with feces, especially old feces.
- Like all mammals, donkeys are susceptible to rabies virus but infections are not particularly common. Raccoon rabies has also be identified in the area, and a bite from a raccoon may have been the source.
- A York County woman was bitten by a kitten that ran into her house when the door was opened for someone else. The kitten bit her when she grabbed it to throw it (hopefully not violently) back outside... an understandable reaction but not what you want to do in a case like this. You need to know whether a wild animal that bites is rabid, and if it gets away, you can't test it. You need to get away from it but keep it contained until someone can come get it. The other problem with people getting rid of the animal is that they might not recognize the risk of rabies. In this case, the kitten was hit by a car after being removed from the house, which allowed for it to be tested.
Yet another report of a dog being exposed to rabies through contact with wildlife, then being euthanized because it was not properly vaccinated.
- An unvaccinated animal that has been exposed to a rabid animal has to be euthanized or undergo a strict six-month quarantine. A vaccinated animal only needs a 45-day observation at home.
- Encountering a manic bobcat isn't something I'd like to do, and a LaCrosse, Florida woman spent nine days in hospital after being attacked by one. The 25-pound cat was trying to get the family's cat, then lunged at the woman when she came outside the house, aiming for her neck. Her husband then shot it. They knew that the bobcat needed to be examined, and took the rather unusual approach of bringing it to the hospital emergency room with them (I'd love to have seen that). I don't imagine hospital personnel did anything, but Florida Fish and Wildlife Conservation Commission personnel came and got it, and later confirmed that it was rabid. (Image: Lynx rufus, US Fish & Wildlife Service)
It's very common for kennels to require dogs be vaccinated against "kennel cough" before they are allowed in. There are two main reasons for this:
- Reducing the risk that a dog will bring kennel cough into the facility and spread it to other dogs.
- Reducing the likelihood that a dog will acquire kennel cough if someone else brought it in.
Overall, it's a sound policy, but it's far from 100% effective and it needs to be part of an overall kennel infection control program to work. Relying solely on vaccination to prevent kennel cough is a weak approach that can ultimately fail, particularly if other infection control practices are poor or if vaccination protocols are illogical.
Why isn't it 100% effective?
1) Kennel cough is a syndrome, not a specific disease. It can be caused by many different viruses and bacteria, often in combination. Kennel cough vaccines are typically targeted against Bordetella bronchiseptica +/- canine parainfluenza, two important causes of kennel cough, but not the only causes.
2) No vaccine is 100% effective. Vaccines help reduce the risk of illness, but they don't completely eliminate it. Some vaccines are better than others, and some animals respond better to vaccines than others.
3) Timing is another issue. One of the weak points of many kennel protocols is the requirement that the dog be vaccinated "before entry," or within a certain number of weeks or months. The problem with this is vaccines are not immediately effective. What often happens is people decide to board their animal at the last minute or realize the night before that they need their dog vaccinated, so the vaccine gets given a day (or less) before kenneling. The intranasal kennel cough vaccine (squirted up the nose) takes a few (3-5) days to be effective, and the injectable vaccine takes even longer (a week or more). Vaccination very soon before boarding, particularly for a dog that has never been vaccinated against kennel cough before, is unlikely to result in protection from infection by the time of boarding.
Requiring vaccination before boarding makes sense, but it's important to remember that:
- It's not 100% effective.
- It doesn't negate the need for a good infection control program.
- It needs to be given at an appropriate time to be effective.
An interesting paper in the journal Emerging Infectious Diseases (Page et al. 2011) describes an impressively large effort to study the effect of anthelmintic (dewormer) baiting on parasite contamination at raccoon latrines sites in Indiana.
Raccoon latrines can be highly contaminated with various parasites, because raccoons congregate at these sites and use them as "communal toilets." Of all these parasites, the raccoon roundworm, Baylisascaris procyonis, gets the most attention. It is very common in raccoons, but it is also a very rare cause of disease in people who swallow the infective parasite eggs from the environment. In some of these people the parasite larvae can cause very serious neurological disease which can be very difficult to treat.
In this study, the research team identified 559 raccoon latrines in north-central Indiana. They removed debris from the areas and used a torch to help kill the parasite eggs that were there (this is one of the very few effective ways to kill the very hardy eggs of Baylisascaris). At a selection of latrine sites, they also collected baseline fecal samples. After this was all done, they distributed dewormer (pyrantel pamoate) baits in half the areas once a month (leaving the other half of the areas as controls). They then collected fecal samples at all the latrine sites approximately 6, 12 and 18 months later.
Fecal samples were tested for B. procyonis eggs. Also, they captured mice from some of the study patches. Like people, mice are intermediate hosts for B. procyonis, and they can be infected in the same manner, so researchers looked for B. procyonis larvae in the brains of the mice.
Overall, they tested 1797 fecal samples. In the first round of sampling, 33% of samples contained B. procyonis eggs. The prevalence of eggs decreases significantly (3-fold) after baiting by the first recheck, and stayed at that level throughout the study. By the one-year sample time, there was also a significant decline in B. procyonis larvae in the brains of mice (27% vs 38%).
This impressive study shows the potential impact of controlled and somewhat practical interventions on the presence of some concerning microorganisms. Certainly, no one is going to be able to treat all raccoon latrines with a torch. However, dewormer baiting might be a consideration in areas that are close to human populations, along with other control measures. Dewormer baiting could be relatively cost-effective in this case. It won't eliminate the problem, but it might help reduce environmental contamination and the associated potential for human and domestic animal exposure.
The situation occurred in March 2010, when a stray dog taken to a North Dakota animal shelter was diagnosed with rabies. An investigation was undertaken to look into human and animal exposure.
- Potential exposure was investigated in 32 people. Of these, 21 were determined to fit criteria for requiring post-exposure prophylaxis. This included nine shelter employees and one volunteer.
- Twenty-five dogs at the shelter were considered exposed. According to the report "In accordance with 2009 Compendium of Animal Rabies Prevention and Control guidance (1), the 25 dogs in the shelter with the rabid dog were euthanized." That's a somewhat misleading statement. Immediate euthanasia is not the only recommendation in this kind of situation, it's just one of the options. In a dog that has not been vaccinated (or whose vaccination status is unknown), euthanasia OR six months of strict quarantine is indicated. The decision to euthanize was probably a logistical one, not being able or wanting to quarantine this many dogs for such a long period of time. It's a reasonable decision given limited isolation capacity (and budget).
- Twenty-five other unvaccinated dogs that were adopted or claimed by their owners were also exposed. (Presumably, these were dogs that had contact with the infected dog, then went to homes before the rabid dog was diagnosed). Of these, 11 were euthanized, 13 were quarantined for 6 months at home, and one was 'unintentionally killed' (whatever that means). All euthanized dogs were tested and were negative for rabies.
A few issues were raised in the report:
Rabies vaccination of shelter personnel: "In addition, preexposure prophylaxis for animal shelter workers or other persons whose activities bring them into frequent contact with potentially infected animals should be considered, in accordance with Advisory Committee on Immunization Practices recommendations (6)" This is a complex issue. It would be ideal for all shelter employees to be vaccinated, and I'd love to see that done. The problem is actually getting it done. Shelters often have many employees and volunteers, and a very transient worker population. Getting all these people vaccinated is tough. Vaccinating short term, part time and temporary employees is tough enough, let alone volunteers. Cost is also an issue. Is it realistic to make people volunteering or earning low wages to pay the expensive cost of vaccination? Can shelters afford to pay for vaccination? What happens if someone doesn't want to be vaccinated? This is an ongoing issue in shelter medicine and one where there is no clear consensus. Shelter personnel clearly fit standard recommendations as being a group in which vaccination should be considered, but it's easier said than done.
Vaccination of animals: "First, all domestic animals should be vaccinated against rabies, in accordance with guidelines (1,8)." This is another issue that is very good in principle but tougher in practice. Rabies vaccination must be done by a veterinarian in most regions, and most shelters do not have a resident veterinarian. Getting animals vaccinated promptly after admission can be difficult. Ideally, shelters would have better and closer relationships with veterinarians, but it's quite variable (and an area that needs improvement). Vaccination would also not help much in some situations, since it does not result in immediate protection. Dogs that are vaccinated are not considered protected for 28 days. Therefore, even if they were vaccinated at arrival, some of the dogs in this situation would still be considered unprotected. Nonetheless, I don't want to dismiss the role of vaccination, and I think shelters need to significantly increase rabies vaccination rates. It's not a simple problem, however.
Contact in the shelter: "Second, animals without documentation of vaccination against rabies should be kept separate from the public, wildlife, and other animals to prevent transmission of the virus (5,8)." Another "good in principle, but have you ever been to a shelter?" statement. Shelters don't have lots of space. Having enough room to properly separate incoming, sick, and adoption animals is hard enough. Having to separate all those groups into rabies-vaccinated and non-vaccinated, or individually isolate animals, is going to be impossible logistically in most facilities. The concept of cohorting animals of different risks is excellent and can be improved on, it's just not possible to isolate all animals that are unvaccinated or of unknown vaccination status (i.e. almost every animal coming into a shelter). This is particularly true since they are not considered protected until 28 days after vaccination.
Infection control practices: "In this case, 36 dogs had to be euthanized because employees and volunteers might not have consistently followed the shelter's policy of preventing muzzle-to-muzzle contact between dogs." Compliance with infection control practices is an issue, and it could be improved. It's an area we're working on now.
Definition of contact: In this particular situation, a very broad definition of contact (that may result in exposure) was used. "Although the shelter's animal handling policies likely minimized contact among dogs, muzzle-to-muzzle contact could not be ruled out; therefore, BOAH and NDDoH recommended that all dogs present in the shelter from March 9--20 be euthanized." It's quite unlikely that any of these other dogs were truly exposed if this is the only kind of contact they may have had with the rabid dog. Balancing public health and animal welfare is difficult. Certainly, you need to err on the side of caution, but how far do you go? Quarantine would have been ideal because of the extremely low likelihood of exposure, however if it's not practical (or feasible or affordable) in a shelter situation, euthanasia may be the only option.
This was a bad situation but it's not surprising, nor will it be the last time it happens. A single rabid dog led to the euthanasia of 36 other dogs, and expensive (and probably stressful) treatment of 21 people. Shelter management can be improved to reduce the risk of this happening, but there's no way to absolutely prevent it.
Many people think of rabies as a very rare disease primarily associated with wildlife, however canine rabies kills tens of thousand of people each year, making it a leading cause of infectious disease deaths in some areas. China is an example of such a region, and rabies is a serious problem throughout much of the country. For example, last month 33 people died of rabies in Guangdong province, according to the the Provincial Health Bureau. That means that there were more deaths from rabies than tuberculosis in the region (there were 80 deaths from AIDS, 33 from rabies and 14 from TB).
The frustrating part is that the vast majority of rabies infections can be prevented with basic medical care, consisting of timely administration of rabies post-exposure prophylaxis, and vaccination of both feral and pet dogs.
A recent paper about rabies post-exposure treatment in animals (Wilson et al, J Am Vet Med Assoc 2010) also contained some interesting information about rabies vaccine failure in pets. The study, which looked at data from more than 1000 animals in Texas from 2000-2009, mentioned a vaccinated 15-month-old cat that developed rabies. It had been vaccinated at 5 months of age and was not yet due for a booster, which would have been required at 17 months of age.
Rabies was also diagnosed in a dog and cat that had been vaccinated but were overdue for their boosters. Both initially received one dose of a 3-year vaccine, but they did not received the booster that is supposed to be given 1 year later. (Even with 3-year vaccines, pets are supposed to be given their first booster (i.e. their second dose of vaccine) after 1 year, before moving to getting boosters every 3 years). The dog was vaccinated 2 years and 9 months earlier. Twelve days after being exposed to a rabid skunk it was given a booster, but it developed rabies nonetheless and died 8 days later. The cat was vaccinated 2 years and 3 months earlier. It apparently did not receive a booster after it was exposed to rabies, and subsequently also died of rabies.
Another six dogs and three cats that were vaccinated developed rabies, but all of these were overdue for their booster or had been vaccinated less than 30 days before rabies exposure. These were therefore not considered vaccine failures.
This information should not be taken as an indication that rabies vaccination is not useful or that current vaccination protocols are inadequate. This involves a very small number of animals, and only one that was properly vaccinated. Rather, it should be a reminder that vaccination is not infallible and that the possibility of rabies cannot be summarily dismissed just because the animal has been properly vaccinated.
If an unvaccinated dog is exposed to rabies, the typical requirement is a strict six-month quarantine (with rabies vaccination one month into quarantine or one month before the end of quarantine) or prompt euthanasia.
Why? There has been only limited investigation of rabies post-exposure treatments in dogs. Ineffective post-exposure treatment could put the people around an exposed dog at risk of rabies exposure themselves. In the absence of convincing evidence, public health concerns trump animal issues.
A recent study published in the Journal of the American Veterinary Medical Association (Wilson et al 2010) sheds some more light on the topic. The authors reviewed records from rabies-exposed animals in Texas from 2000-2009, where a different post-exposure protocol is used for animals. In Texas, exposed unvaccinated animals are either:
- immediately euthanized, OR
- immediately vaccinated, kept in strict isolation for 90 days and given rabies vaccine boosters during the 3rd and 8th week of quarantine.
The authors reviewed the records of 1014 animals (769 dogs, 126 cats, 72 horses, 39 cattle, 3 sheep, 4 goats and 1 llama) that were treated with this modified protocol after exposure to another animal that was confirmed to be rabid.
None of the treated animals developed rabies.
An important issue to bear in mind is whether the animals in the report were actually exposed to the rabies virus itself, not just a rabid animal. There's no way to prove that any were actually exposed to the virus, however 29% had what was considered "direct exposure," and a further 38% had "probable exposure." Presumably, not all the animals were actually exposed, but even so, because they looked at so many animals, it provides more convincing evidence that the protocol is effective for preventing rabies. The only definitive way to figure it out would be to experimentally infect animals with rabies and then see if the post-exposure treatment prevents them from developing disease, something that is unlikely to be done for many reasons.
Immediate vaccination may be a key component of this protocol. Previous reports of post-exposure treatment failure have been cases where there was a relatively long interval (e.g. a couple of weeks) from rabies exposure to first vaccination. By that time, it's possible that the infection is too advanced, particularly since the typical incubation period for rabies in dogs is 21-60 days.
The Texas post-exposure protocol makes sense. It appears to be effective and requires a shorter quarantine period. Those are both important factors, and make post-exposure treatment a more viable option.
However, while this study provides evidence that this protocol may be effective, it doesn't mean everyone can just start using it. Regional laws regarding rabies exposure supercede these results, and unless the rules are changed, this approach may not be an option. Hopefully, regulatory officials will look at the results of this study and Texas' experience, and think about modifying their own protocols.
At the end of the day, however, it's still much better to have your animal properly vaccinated against rabies so that post-exposure treatment or quarantine isn't needed. Vaccination isn't 100% effective, but it's very good overall, and the mandated response to exposure of a vaccinated animal is much easier (on both the animal and owner) than for an unvaccinated animal.
The UK's Veterinary Medicines Directorate (VMD) has taken the long-overdue step of requiring people selling alternative therapy products for prevention and treatment of diseases in animals to actually show that the products are safe and do what they claim. The effort includes products like homeopathic nosodes, nutraceuticals and herbal preparations.
Historically, alternative medicines have received little regulatory scrutiny, and manufacturers have blatantly disregarded rules about what they can and can't say about their products. As a result, many products have claims of safety and effectiveness that are not based on any evidence whatsoever. While this may simply result in people wasting money in many situations, there are concerns that the products could actually do harm in some cases, and that some people may use untested "alternative" treatments instead of proven traditional therapeutics. In these situations, using poor quality ineffective products can obviously also harm an animal's health. Since the alternative medicine industry has shown an obvious lack willingness to self-regulate, the government is required to step in.
It's hard to say how aggressive the VMD will be, and it's likely that it will take some time to straighten out the false advertising. To start, the VMD will be contacting manufacturers to request proof of safety and evidence supporting any health claims that they make.
This doesn't mean that these products will be banned. While there are basically no studies supporting the effectiveness of close to all of these products, they are not being taken away from consumers. Rather, the key is making sure the label claims are accurate so consumers can make a better informed choice. If a product hasn't been shown to cure disease X, it shouldn't say on the label that it does. If manufacturers don't want to do the studies to show effectiveness, they can still sell the product, they just can't make these claims on the label. Assessing safety is tougher, since these products typically lack any safety trials, and it's unclear what degree of safety testing/evidence the VMD will require.
This is a welcome change. Alternative therapies are still therapies. It doesn't matter if they are herbal, otherwise "natural" or manufactured. They can be (or contain) powerful substances and it should be the legal (and ethical) duty of manufacturers to properly test and advertise their products. Only with good quality control and proper research will we be able to understand the role of alternative therapies in patient care.
In the interim (to bring this back to an infectious disease-focused post), it is critical that unproven therapies not be used in place of standard approaches when dealing with the treatment or prevention of infectious diseases. Using these products as supplemental therapies is usually fine. Just don't risk a pet's health using unproven treatments alone when better-investigated options are available.
Probiotics are widely available and increasingly popular as "alternative" or "natural" approaches to treatment and prevention of disease. When considering the use of probiotics, it's important to think about what a probiotic really is. A widely used (and my favourite) definition is:
Probiotics are live microorganisms that, when given in adequate doses, provide health effects beyond that of their inherent nutritional value.
It's a great definition and has some key points to consider:
- Live microorganisms must be present. That's not always the case with commercial products.
- An adequate dose must be present. Some commercial products have very low levels of viable microorganisms. We have limited information about the required doses, and these would vary between bacterial species and animals species, but the low levels present in some veterinary probiotics are a major limitation.
- There must be a health effect. This is the key. If it doesn't do something beneficial, then it's not a probiotic.
Which brings me to my "head shaking product of the day": probiotic floor cleaner. Yes, floor cleaner. And it has a nice warm-and-fuzzy name: Peace of Mind Floor Cleaner.
According to the manufacturer, it reduces the risk of infection (infection of what, by what and how, are completely unclear). It also allegedly "keeps protecting surfaces for up to 3 days by leaving a long-lasting layer of beneficial probiotics that create a safe, stable and odor free environment. Don't let your floors make you crazy."
I didn't realize that floors were the cause of such angst and that covering them with probiotics can improve your life (hopefully the sarcasm is apparent).
What does this have to do with probiotics for treatment or prevention of disease in animals? Not a lot. But it shows how easily people can throw around the word "probiotic" as a marketing tool. Floor cleaners can't be probiotics since they aren't ingested and don't have health effects. However, the same type of scrutiny needs to be applied to any probiotic that you are considering using.
- Demand evidence of a health effect (real evidence, not just testimonials).
- Demand information about the recommended dosing.
- Find out what specific bacteria are being used.
- Don't stop thinking once you read "probiotic." On the contrary, when you read "probiotic" you should start thinking and asking questions.
Humane societies and shelters are often overwhelmed by the number of animals that come in. It's pretty uncommon to see much (if any) empty space in most shelters, and overcapacity shelters lead to increased risk of disease transmission, outbreaks and suboptimal care of the animals that are there.
One way of helping deal with overcrowding is fostering animals to people's homes for periods of time. Typically, foster homes take animals when shelters are at capacity, or take specific animals such as nursing cats, which are more difficult to care for properly in a shelter.
Most places have protocols for fostering, but they're not always very comprehensive and they don't always adequately cover some important areas. If you are thinking about fostering shelter animals, you need to think about the risks and whether you can manage them.
Are there people in the household that are at increased risk of infection?
Fostered animals should be assumed to be at higher risk of carrying and transmitting various infectious diseases. They can have high rates of carriage of various intestinal bacteria and parasites, along with a host of other microorganisms (e.g. ringworm). They may also be more likely to bite and scratch, not necessarily because they are aggressive, but often because they are young animals that may do so when playing. They may also be more likely to poop in the house.
Households with children under the age of 5, elderly individuals, pregnant women or people whose immune systems are compromised are at increased risk of various infections, both in terms of the likelihood of becoming infected and the likelihood of developing more severe disease. Households with these types of individuals should not foster animals. They are much better off having their own lower-risk pets.
Are there any "resident" pets in the household?
You might expect that someone willing to foster animals would also have their own pets, but that's not always the case. Non-pet owners are actually ideal, since this negates any risk of diseases being spread from or to household pets that live there long-term. However, it's more typical that foster homes also have such resident pets.
Are there any pets in the household that are at higher risk for infection?
As with people, there are some animals that are at increased risk of infection. These include the very young, very old, pregnant and pets with compromised immune systems. The latter group would include pets with chronic illnesses, those being treated with high doses of steroids for various diseases, animals with cancer, animals with diabetes, and a range of other issues. People owning a pet that fits into one of these categories should not foster animals because of the risk to their own pet.
How do you reduce the risks associated with fostering animals?
- May sure there are no high risk people or pets in the household.
- Make sure the shelter or organization knows what they are doing. Make sure they have a clear protocol that says who will be fostered and how it's done.
- Look at the animal before you get it. Visit it at the shelter. See if it looks healthy. If you have any questions, make sure it's examined by a vet before it reaches your home.
- Use good hygiene. Wash your hands regularly. Properly clean up feces and clean litterboxes regularly.
If you have pets of your own:
- Make sure they are vaccinated and on an appropriate parasite control program.
- Keep the new animal away from your pet at the start. That lets you find out more about the animal, and it gives you more time to see if there are potential infectious disease concerns.
- Do a controlled introduction of the new animal. Slow, supervised introduction of the animals can reduce the risk of bites or scratches.
Fostering is a good way to reduce pressures on humane societies and shelters, and to provide better care for some animals, like pregnant animals or those with young kittens/puppies. A good fostering program can be set up with limited risk to all involved, but infectious disease risks can never be completely eliminated. By accepting a new animal into your house, you increase the risk of exposing yourself and anyone else (human or animal) to infectious diseases. That's just a fact of life.
The California Veterinary Medical Association has published recommendations for dog park safety. The document, entitled "Dog parks harbor risks as well as fun" emphasizes the benefits of park visitation but points out some risks and recommended precautions. Some of the risks associated with park visits include bites, scratches, and exposure to various infectious diseases.
Some basic and practical precautions that are recommended include:
- Ensure your dog's vaccination status is current.
- Make sure your dog is socialized and behaves well around people and other animals.
- Monitor your dog closely.
- Avoid mixing small dogs and big dogs.
- Bring water for your dog to drink.
- Clean your dog's paws when you leave the park (I'm not sure that one's very useful).
- Have your veterinarian check your dog regularly for parasites (and other infectious diseases or risk factors).
- Talk to your veterinarian about any (other) precautions you should take.
Overall, the document provides some useful and very practical information. A few things I would add:
- Keep your pet away from the park when it's sick.
- Make sure you promptly pick up dog poop and dispose of it properly.
- If it's an off-leash park, spend a few minutes watching the other dogs that are there before deciding whether to let your dog off its own leash.
- Make sure your veterinarian knows that your dog goes to the park if it becomes sick. There are some diseases that are more likely in dogs that visit parks, and outbreaks can also be associated with parks. Knowing that your dog has access to a dog park might be an important part of the diagnostic process. As well, knowing that you visit the park regularly might change your veterinarian's recommendations for vaccination and deworming.
Veterinarians are reporting a potential cluster of leptospirosis cases in dogs near Lake Aquitaine in Mississauga (Winston Churchill Blvd. & Derry Rd. area). Leptospira gryppotyphosa has been confirmed in one dog, with other cases being suspected but not confirmed because owners declined testing.
Leptospirosis is a bacterial infection caused by different types Leptospira spp. These bacteria like to live in water and in moist conditions, and infections in dogs most often result in kidney disease. The bacterium is shed in the urine of infected animals. Leptospira gryppotyphosa is mainly found in wild voles, raccoons, skunks and opossums, and these animals can infect various environmental areas. Any animals exposed to outdoor environments in endemic areas can become infected from ingesting infected water or from contact of infected water with the mouth, eyes or nose, or cuts or other broken skin.
People in the area where these cases have been found should take particular care and probably avoid letting their animals wander into the water or wet areas. A vaccine is available to reduce the risk of leptospirosis, including disease caused by this Leptospira type. Vaccination of pets that are exposed to water or wet habitats in areas where lepto is present is a good idea. People in the Lake Aquitaine area should be particularly vigilant and vaccination of pets would be a good idea.
ProMed's monthly rabies update contains some recurring themes:
- A couple of incidents of dog versus rabid raccoon. The dog usually comes out on top, but the raccoon can exact revenge at the end of the day through the need for quarantine or euthanasia. If the dog is not vaccinated, a long quarantine or euthanasia is required. If the dog is vaccinated, only a shorter observation period is needed.
- A rabid skunk was found wandering around during the day with a wobbly gait and drooling. Any wild animal that is acting strangely should be considered rabid until proven otherwise. They don't have to be showing signs of severe neurological disease. Something as simple as not being afraid of people or wandering around in areas or at times when they would not usually be found should raise the suspicion.
- A child who was sleeping outside woke up to "find a raccoon, kind of, scratching at his leg." (I assume they mean it was "kind of scratching at the kid's leg," (whatever that means), instead of it was "kind of a raccoon.") The raccoon wasn't caught for testing but the child is undergoing post-exposure treatment because a normal raccoon wouldn't be expected to do that, so there is a significant chance of rabies exposure. Scratches are not high risk since rabies virus does not live in the claws, however it is possible that saliva from the raccoon could have been present on the animal's feet or the raccoon could have licked the child before scratching, such that the scratches could have then inoculated rabies virus into the tissues.
- A couple of reports of rabies in rabid kittens. These cute little rabies vectors cause repeated problems, and lead to public alerts notifying anyone who may have handled the kittens to get evaluated to see if they need post-exposure treatment. Handling of strays should be avoided.
- A family received post-exposure treatment after being bitten by their rabid cat. Vaccination of pets is not just for the health of the pet. It's to reduce exposure of people as well.
To me, a good general rule is "avoid buying things that are offered for sale at discount prices by a guy in a parking lot." Unfortunately, many people can't seem to pass up a "bargain" and can end up paying more in the end.
A good case in point is a man who was offering rabies vaccination of pets in retail parking lots in southern Oklahoma. James Allen advertised his vaccination "business" on Craig's List and set up shop in various parking lots. He also signed vaccine certificates and listed himself as a veterinary technician. (One problem is that veterinary technicians aren't allowed to sign rabies certificates. Another is that he is not one). Mr. Allen has yet to be apprehended.
Mr. Allen is suspected of vaccinating hundred of pets with what is, at least from a regulatory standpoint, worthless vaccine. Since the vaccine wasn't administered by a veterinarian, all of those animals are considered unvaccinated. Therefore, if they are exposed to rabies, they face the prospect of euthanasia or a strict six-month quarantine.
Rabies vaccine must be given by a veterinarian in order for government authorities to consider an animal vaccinated in most regions. Mandating that rabies vaccine be administered by a veterinarian isn't a money-grab or veterinarians protecting their turf - it's a government regulation aimed at protecting pets and the public. Restricting rabies vaccination to veterinarians helps ensure that only proper vaccine is used, that the vaccine has been properly handled and administered, and that vaccination is adequately documented. In the absence of clear proof that an animal was properly vaccinated, it has to be considered unvaccinated, because you must err on the side of caution with a deadly disease like rabies.
It's pretty sad that it's so easy to get rabies vaccine in Oklahoma. It should only be available for purchase by veterinarians, but it's apparently easy to obtain from farm and ranch stores. Apparently, stores in Oklahoma can sell the vaccine but are supposed to post a notice saying animals are not considered vaccinated if it's used. Why you'd allow a store to sell the vaccine when you don't recognize it as effective is beyond me, but that's what's happening.
Among the most despicable of the recent consumer frauds in China is the sale of counterfeit rabies vaccine. Eight people in south China's Guangxi Zhuang Autonomous Region have been arrested for producing fake vaccine that may have resulted in the death of one child, and threatened 1000 other people.
The fake vaccine was identified during the investigation of the death of a four-year-old child in December 2009. The child was bitten by a rabid dog and received a series of vaccines from a local clinic. Despite the treatment, he died a few weeks later.
There are at least a couple of very serious concerns with counterfeit rabies vaccines:
- The use of fake, ineffective rabies vaccine for post-exposure treatment in place of real vaccine could result in deaths that could have otherwise been prevented. Rabies is basically 100% preventable if proper treatment (with an effective vaccine) is administered in a timely manner. Without this treatment, exposed individuals are at risk of developing clinical rabies, which is basically 100% fatal.
- Poorly prepared vaccines could themselves lead to serious adverse reactions, because they may contain any number of contaminants to which the body may react. Contamination of "fake" rabies vaccine with live rabies virus is not out of the question - the use of such a counterfeit contaminated vaccines could actually give a person rabies instead of preventing it.
It's not clear which of the above scenarios may have resulted in the death of the four-year-old boy last year. The child died about three weeks after being bitten by the dog, and had clinical signs of rabies at the time of death. Three weeks is an extremely short incubation period for natural infection, but it's not impossible. Short incubation periods can occur, especially with severe bites to the head or neck (the location of the bite in this case was not reported). However, if the "fake" rabies vaccine used to treat the child was contaminated with live rabies virus (which is possible), then it's not impossible that the boy didn't get rabies from the dog bite, but rather was infected by the contaminated vaccine.
Either way, it's not a good situation. Rabies is a major problem in China, with over 2000 deaths last year alone. The last thing people need is confusion about whether they should be vaccinated and fear that the vaccine might be worse than the bite.
The Philippine Information Agency has issued a press release detailing a rabies vaccination program for 5000 public school children in the province of Camiguin. This is prophylactic (preventive) vaccination, not post-exposure treatment.
Routine rabies vaccination is recommended for people at increased risk of exposure. Classically, this involves veterinary personnel, people working with wildlife, people working with strays or feral animals, and similar groups. Routine vaccination of the general public is not used because of the high cost and low need, given the average person's low risk of exposure and the availability of effective post-exposure treatment. By providing vaccine prophylactically, authorities are implying that the rabies exposure risk is quite high for these children.
A Camiguin health office official is reported as saying that the pre-exposure series, consisting of 2 doses, will save money compared to the post-exposure regimen of 4 doses plus a shot of anti-rabies antibody. However, that doesn't make any sense. From a cost standpoint, prophylactically treating everyone with 2 shots only saves money if over half of the population would otherwise need 4 shots. I know rabies is a problem in that area, but certainly half of the kids in the area won't exposed. Further, what really blows a hole in this reasoning is the fact that a vaccinated person who is exposed to rabies should receive a booster series of 2 vaccines regardless, thus bringing the total to 4 shots. People who have been vaccinated don't get the antibody shot if they are exposed, so that does save a little money. (On a side note, routine vaccination usually involves 3 doses, and the release says people will get two doses but will get vaccinated on days 0, 7 and 21 or 28. That's 3 doses, which makes the math even more questionable).
If rabies is epidemic in the area, if it's not being controlled well by other means and if there is rampant exposure of children, vaccination may be a reasonable option. However, rabies is basically 100% preventable with proper post-exposure treatment. Rabies deaths are usually because people don't seek, or are not given, proper treatment in a timely fashion. Educating the public to reduce the risk of rabies exposure and to seek medical care, ensuring that there is adequate awareness about rabies among medical personnel and ensuring that adequate vaccine and antibody is available for exposed individuals seems to be a much more logical approach
I was actually wondering whether this press release was real. I did some searching and this agency is an official government agency and a member of the presidential communications group. It would be really nice to see more details about why this decision was made, particularly some of the evidence that was used to determine that this was needed.
It's important to take rabies control seriously. The main problem with rabies in many areas is a lack of effort or adequate resources directed against stray animal control, animal vaccination, public education, medical education and availability of proper treatment. Working on those would seem to me to be a better approach than an expensive and somewhat questionable mass vaccination program of children. The reasoning in the press release is that kids might not report bites, and that is a good point to consider. But, does that actually occur and can it not be controlled by better education?
What's the cost-benefit of rabies vaccination in a situation such as this? It's hard to oppose vaccination of this fatal disease, but are there other ways to provide better overall protection?
The other night, my daughter woke up yelling that she was "scratchy." She was quite upset and it continued for a while, despite my best attempts to calm her down. She had a bit of a fever and shortly after broke out in a good case of hives all over her body.
How is this relevant to this blog? Well, earlier that day, she was at the doctor's for her 3-year checkup. She wasn't vaccinated, but Heather made the observation that had she been vaccinated at that appointment, we would have wondered whether this was a vaccine reaction.
Determining whether something is a vaccine reaction can be tough. Too often, people blame a wide range of abnormalities on vaccination, without realizing that they occur at other times too.
The post I wrote a couple of days ago about rabies vaccination mentioned people not vaccinating their horses because of fear of vaccine reactions. I think it's fair to say that there are many more people that think their horse has a problem with vaccines than there are horses that truly have vaccine reactions. Sometimes, people are looking for an excuse not to vaccinate. Often, however, they are really convinced that a vaccine reaction occurred, even though the evidence may be weak.
A good example of this is West Nile virus vaccination. When West Nile virus vaccine first became available, there were rumours that it caused stillborn and deformed foals. There were internet sites reporting cases and publishing pictures of aborted fetuses. However, just because a mare was vaccinated and later aborts, that does not mean that the vaccine caused the problem. Lots of mares that aren't vaccinated have problems. That's why we do research - to see if problems like that are more common in vaccinated horses versus unvaccinated horses. Despite the internet paranoia, there is no evidence that West Nile virus vaccination produces dead or deformed foals, and fortunately this rumour seems to have died down. (I have to wonder how many horses died from West Nile because they weren't vaccinated as a result of this rumour. When some people stopped vaccinating children for measles because of false concerns about autism, there were tremendous increases in measles cases in many areas.)
Vaccine reactions can and do happen. There's no disputing that. Most are mild but some can be severe. However, lots of animals can develop identical-looking of problems at any given time. Just because they were vaccinated recently does not mean that the vaccine caused the problem. A vaccine reaction should be considered when abnormalities develop around the time of vaccination, but automatically blaming the vaccine must be avoided.
Some things to consider:
- Has the horse had this specific vaccine before? A reaction is probably less likely if the horse has had this specific vaccine multiple times in the past with no problems.
- Is the problem something that is typically observed with a vaccine reaction? Development of hives after vaccination is pretty suggestive, although it's not definitive. Other problems may be hard to link to vaccination.
- Was a single or combination vaccine used, or were multiple vaccines given at the same time? If a combination vaccine was used and the potential reaction wasn't severe, giving the specific components of the vaccine individually next time might help determine if it is a vaccine reaction and which component caused the reaction. There's no use stopping all vaccinations if the horse might only be reacting to one specific component. Sometimes, avoiding combinations is all that is needed (although whether that's because it decreases the risk of reactions or whether there wasn't actually a vaccine reaction in the first place is debatable). If there is a problem with one component, then that single component can potentially be skipped but the other vaccines still given.
- Was it a severe reaction? If not, then not having the vaccine may be a bigger risk than vaccinating. It depends on the disease and the risk of exposure. Also, pre-treatment of the horse with an anti-inflammatory may be enough to prevent a mild reaction or decrease the severity of a more significant reaction.
- Are there some horses that have severe reactions and can't be vaccinated safely? Yes, but there are very few. Vaccination decisions need to take into account the cost-benefit, in terms of protection and adverse effects. Sometimes, the risks are greater with vaccination, but usually they are not. If you think your horse has a problem with vaccines, work with your veterinarian to determine the best approach. Don't let a knee-jerk reaction automatically prevent you from vaccinating.
Image: A horse with hives along its neck (click image for source)
This Worms & Germs blog entry was originally posted on equIDblog on 16-Sep-10.
TheHorse.com's latest reader poll asked the question "If you knew rabies had been found in wildlife in your area, would you vaccinate your horse for it?"
- 79% of respondents said they already vaccinate against rabies annually.
- 16.5% said they don't currently vaccinate but would if it was found in wildlife in the area.
- 4% still wouldn't vaccinate.
The high vaccination rate is very encouraging and is a good sign, considering that rabies, while rare, is 100% fatal in horses and is preventable with early vaccination.
Here are some reader comments (with some additional commentary from me):
Develop a strong immune system instead try to avoid all the drugs
- Keeping your horse healthy is a good disease prevention measure, but it is not good enough for prevention of rabies. This is a foolish approach to rabies prevention.
Used to yrly. vaccinate in MI, but vets here in KY don't recommend it/My Vet keeps telling me it is not necessary, same with my daughter horses. I disagree.
- This, and a few other comments about veterinarians not recommending vaccination is very surprising and concerning. Rabies vaccination is considered a "core" vaccine in North America and it makes no sense for veterinarians to be actively discouraging vaccination.
Too many adverse reactions...bad outbreak, might reconsider/There have been too many adverse reactions to the vaccine, I won't take the risk of vaccinating.
- Adverse reactions can occur with any vaccine, but they are quite rare with rabies vaccine. Sometimes, horses react when they are given a variety of vaccines at the same time, and it might not be rabies vaccine with that caused the problem. Often, the risk of adverse reactions is just used as an excuse not to vaccinate, even if the horse has never had a problem.
Vaccination is necessary when horses are turned out nearly 24/7
- Yes. It's also necessary when horses are inside 24/7. Wildlife (especially bats) easily and often get into barns.
I don't vaccinate yearly because I test titers and they remain high for many years.
- Titre testing is not useful because we don't know what a protective titre is. You can take a titre and get a result, but that doesn't mean the horse is protected. Also, if your horse is exposed, it would be considered unvaccinated by government officials if it had not been recently vaccinated, regardless of titres.
I would be especially diligent to vaccinate if aware of a wildlife outbreak of rabies/I have only vaccinated when there have been cases of rabies, otherwise, I don't.
- I have a couple of problems with this type of approach. Firstly, you only recognize an outbreak AFTER a large number of animals get sick. Waiting until someone reports an outbreak doesn't help you if your horses are among the first ones affected. Also, rabies isn't a disease that mainly occurs in outbreaks. It is a sporadic disease, where single cases or small numbers of cases pop up all the time. Only worrying about it during an outbreak doesn't help.
I would vaccinate my dogs and cats, but not my horse.
- Why? If there is a risk of the dogs and cats being exposed, there's a risk of the horse being exposed. (Maybe they like their dogs and cats more!)
I can't buy rabies vaccine only vets can get it so I don't give rabies shots.
- So, if I can't do it myself (translation, if I can't do it very cheaply), I won't do it. Not a good infection control program.
NEED ANOTHER CHOICE! I run titers. Vac. is indicated every 3-5 years
- Nope. Vaccination is safe and effective. Standard recommendations are for yearly vaccination. Could we extend that, as is now done with dogs and cats (in which 3 year vaccines are now widely used)? Probably, but we don't have the data to guide us. We can make some reasonable guesses, but do you really want to use a vaccination program designed to protect against a fatal disease to be based on guesses?
The chances of my horses being bit by a rabid critter are slim to none. I don't believe in vaccines
- I don't think anyone can say that the chance of their horse encountering a rabid critter is slim to none. People encounter rabid critters inside their houses, while walking down the street and in various other situations. I certainly didn't plan on catching a rabid bat in my house, but it happened.
- Not believing in vaccines is just ignorance. Vaccination is critical for protection against a wide range of diseases. Can adverse reactions occur? Sure, but they are very uncommon (internet rumour mills aren't facts). Do vaccines prevent infections and save lives? Undoubtedly. What happened when people started avoiding MMR vaccines in kids because of now-discredited autism concerns? Lots of people got sick.
Live in UK, no rabies here generally
- Good reason. Rabies vaccination isn't needed in rabies-free countries.
Fortunately, there were also a lot of logical comments like:
- I never go without this vaccination. it's way to risky!!!
- With all the wildlife around, it's not worth risking an unintended encounter causing big problems.
- Why would you take a chance and not vaccinate...
- Ever since my uncle's horse died of rabies, I have vaccinated all my horses annually.
- Are you kidding? Who'd take a chance with rabies?
And as one person so eloquently put it "DUH!"
Apart from the extremely small small number of horses with known and potentially severe reactions to rabies vaccine (not just any vaccine, specifically rabies vaccine), and those living in rabies-free countries, all horses should be vaccinated.
Image: A Little Brown Bat (Myotis lucifugus) roosting under the eaves of a house (click image for source)
This Worms & Germs blog entry was originally posted on equIDblog on 15-Sep-10.
Israel has experienced a major upswing in canine rabies cases since 2009. There had been a significant decline since 2003, when oral rabies vaccination of foxes was started, but the recent increase has been in dogs and jackals, not foxes. Now, stray jackals and dogs are the main rabies vectors in northeastern Israel, the area affected by the current outbreak.
Stray dogs are a significant concern in terms of rabies because they can have close contact with humans and wildlife. Dogs are the most common source of human rabies internationally and thousands of people die each year from rabies acquired from dogs.
The increase in rabies in stray dogs and jackals has lead to discussions about how to control the stray population and reduce the risk of rabies. Previously, it was common for authorities to shoot strays in parks and nature reserves. This practice was stopped a while ago, however the Israel Nature and Parks Authority has now asked for permission to shoot strays in the interest of rabies control. The proposed regulations would allow strays to be shot in national parks, reserves, and "any other open area where wildlife species are considered at risk", but not unless their presence poses "an immediate discernible risk to wildlife and never within 1 km of human habitation."
This seems to be a wildlife protection program disguised as a rabies control program. The emphasis is on protection of wildlife, since packs of stray dogs have had major impacts on some endangered wildlife (e.g. fallow deer). It's not really a good rabies control program, since culling alone is unlikely to be effective, and only culling when the dogs pose a risk to wildlife and away from human habitation presumably would only have a limited impact on the prevention of human rabies. If they want to control the dog population to protect endangered species, they should just say that. If they want to control rabies, they need a comprehensive rabies control program that involves consideration of various approaches such as vaccination of strays and jackals, sterilization of strays, public education to decrease the risk of exposure, and vaccination of domestic animals. A cull alone won't cut it for rabies control.
Photo: A pair of Golden Jackals (Canis aureus) in Israel (photo credit: Michael Baranovsky)(click for source)
I periodically get questions about whether rabies vaccination is really required or if it's just a good idea. There's not a straight answer because legal requirements vary by region. In Ontario, Regulation 567 of the Protection and Promotion Act states that all dogs and cats three months of age or older that reside in specified areas of the province must be vaccinated. Further, animals must be revaccinated by the date specified on the certificate of immunization. Basically, this means that all dogs and cats must be vaccinated and they must be up-to-date on the vaccination, based on the type of vaccine that was used.
Even if vaccination isn't legally required, if rabies is in an area, it's a good idea because:
- If a pet gets rabies, it will die.
- If a pet gets rabies, owners or other people in contact with it may need post-exposure treatment.
- If a pet gets rabies, it could infect people with this almost invariably fatal disease.
- If an unvaccinated pet gets exposed to rabies, it will need a strict 6-month quarantine or euthanasia. (Euthanasia is common in these situations.) If the pet was vaccinated, all it needs is a 45 day home observation.
Rabies vaccination of pets is easy, cheap and safe, and often required by law.
Image source: http://amcny.wordpress.com
Yet again, a large number of people are undergoing rabies post-exposure treatment because they were exposed to a rabid raccoon that was "adopted" from the wild. In this case, a North Carolina family found a baby raccoon at the side of the road and decided to bring it home. Over the next couple of weeks, various family and friends handled the raccoon, and many were bitten or scratched in the process. The raccoon then died and was identified as being rabid. Forty-five people are now being assessed to determine whether they need to be treated for rabies exposure.
The family dog, which was unvaccinated, has been taken by Animal Control and now faces either a six-month strict quarantine or euthanasia. I suspect the dog will be euthanized.
So, this probably well-meaning but misguided action has resulted in:
- the need for costly post-exposure treatment of many people
- presumably a stressful period for many of those people
- probably the death of the pet dog (although not having the dog vaccinated played a big role here too, since if it was vaccinated, it would only face a 45 day observation period at home, not a strict six-month quarantine or euthanasia).
Fortunately, the raccoon was tested. Otherwise we might be talking about human deaths from rabies, instead of people needing post-exposure treatment. The people who took in the raccoon could also face charges since keeping wildlife without a permit is illegal, but it sounds like that's unlikely to occur.
A few take-home messages from a situation like this:
- Leave wildlife in the wild.
- Vaccinate your pets.
- If you are exposed to an animal that is acting strangely, make sure it's tested for rabies (they did this right, at least).
I had an advice call the other day about two cats that were found with a dead bat. One cat was vaccinated against something (not sure what or when) while the other cat was unvaccinated. This is a situation that, if managed properly, can be very minor, but if handled improperly, can be a major problem, even resulting in death of the animals.
Bats are notorious rabies vectors. The odds of this bat carrying rabies are probably low, but they are not zero and a rabid bat is going to be more easily caught than a healthy bat. Any contact of an animal with wildlife in areas where rabies is present is considered a possible rabies exposure unless proven otherwise. The only way to do this is to have the bat tested.
If the bat is tested and is negative, then everything's fine. If it's positive, then the vaccinated cat would need a rabies booster vaccine and would have to be observed at home for 45 days. The unvaccinated cat would need a strict six month quarantine or would have to be euthanized. So, it's clear that the rabies status of the bat and the vaccination status of the cats are crucial.
Here's what to do in a case like this:
- Get the bat. The bat needs to be tested so you have to maintain control of it. Don't let the cat eat it or run off with it. Don't leave it outside where a person or animal could walk off with it. Put it in a bag or container, without having direct contact with it (e.g. use gloves or a scoop to pick it up). Be very careful if it's not completely obvious that the bat is dead, because an injured bat might look dead but still be able to bite.
- Submit the bat for testing. In Canada, that's done through the Canadian Food Inspection Agency. Make sure they know that an animal has been exposed to the bat. They would not likely test the bat if there was no exposure. They can be contacted directly or through your veterinarian. There is no charge for testing.
- Find out the vaccination status of the cat(s). You need to know when the last rabies vaccine was given and what type of vaccine was used (1 year or 3 year). You need to be able to demonstrate that the pet is current on its rabies vaccination if the bat is positive and you want to avoid the long quarantine.
- Figure out why/how/where the cat(s) caught the bat, and whether that can be avoided in the future.
- Roaming pets + wildlife = bad news: One person's dogs killed a raccoon while out for their "romp around the yard." The raccoon was rabid. There's no mention about the vaccination status of the dogs. If they were vaccinated, they probably got a rabies booster and are under a 45-day "house arrest" for observation. If not, they either need to be placed under a strict 6-month quarantine at a separate facility, or they'll be euthanized. Another report describes a different dog that is now under a 6-month quarantine after attacking a raccoon. In yet another report, a North Carolina woman's dog was euthanized because it killed a rabid fox and was unvaccinated (the owner chose euthanasia over quarantine). That dog is now dead mainly because the owner didn't take the simple and relatively inexpensive step of ensuring that her dog was vaccinated.
- Pissed-off wildlife bite. Sometimes they're rabid too. Get too close at your own peril: A South Carolina man is undergoing post-exposure treatment because he was bitten by a raccoon while removing it from a trap. I'm glad that he had the animal tested. It's pretty easy to see someone in a situation like this just yelling at the raccoon and letting it go, thinking they were bitten because the raccoon was upset and not realizing that they might have been exposed to rabies.
- Some people just don't get it: In response to rabies exposure of close to 50 church members from a rabid bat while on a mission trip, the mission leader stated "It's just part of being in rural America, so there's really not a lot to talk about." Ugh. Rabies exposure should not be written off as some benign, unavoidable rural American experience. It's exposure to an almost invariably fatal disease that requires a series of expensive treatments. It's also not a rural thing. Rabies exposures can occur commonly in urban areas as well.
- Stray kittens can be cute but deadly: A rabid cat and kitten were identified in Ocean City, Maryland, and authorities are looking for people that may have come into contact with them. Human exposure to rabies from handling cute but infected kittens is not uncommon, and sometimes involves a lot of people. If you see a stray kitten, it's best to leave it alone. If you feel the need to rescue it, make sure that you get it to a vet for an exam, and that it subsequently goes somewhere where it can be properly observed and taken care of. If you're bitten in the process, make sure the kitten is quarantined for 10 days to see if it's rabid, or euthanized and tested. The worse case scenario is when people play with stray kittens, get nipped in the process, dismiss it as a minor or playful bite, then release the kitten back into the wild, never knowing whether they might have been exposed to rabies.
Trap/neuter/release (TNR) programs involve trapping feral (stray) cats, then spaying or neutering and vaccinating them. Some cats are adopted, while the majority are released. The goal is to reduce the feral cat population by limiting the number of breeding animals, and to increase overall vaccine coverage in order to reduce illness and deaths. One such TNR program has come under fire in a Texas town.
In Leander, Texas, trapping wild animals (including feral cats) is illegal, but authorities have ignored the rules for groups that run TNR programs. One citizen, Carmen Amaya, is leading a charge to get authorities to start enforcing this so that TNR programs can't happen. The main reason appears to be that she's upset her dog was scratched by a feral cat and ended up with $800 in vet bills (not something I'd be happy with either, but is this really the best way to direct her anger?).
A non-profit group, Shadow Cats, has led the TNR effort and has trapped, neutered and vaccinated about 3000 cats in Central Texas since 2004. About 500 were adopted and the rest released. The organization knows they are working outside the law and have lobbied for it to be changed. That was being considered in June, but opposition from Amaya and others has led to the creation of a task force to make a recommendation, which is due next month. In the meantime, Shadow Cats has ceased activities in Leander.
I'm not sure what the opponents to TNR really want. If it's just cessation of the program, there's no benefit to them. Without the program:
- Stray cats will continue to be around, and there will probably be more of them.
- Potentially adoptable cats won't be taken into homes to improve the lives of those cats.
- Vaccine coverage of the population will decrease. That's a critical point, because it will result in lower "herd immunity." With herd immunity, the greater the percentage of a population that is immune to a disease (i.e. vaccinated), the lower the likelihood of the disease establishing itself in and spreading through the population, even among those individuals who don't get vaccinated.
On the other hand, if these people simply want Shadow Cats to stop releasing the neutered cats back into the neighbourhood, it means either 1) finding a way to care for all those cats in shelter, which simply isn't realistic for a multitude of reasons, not the least of which is cost, 2) releasing the cats elsewhere, which doesn't actually solve the problem, it just makes it someone else's, or 3) euthanizing all the cats instead of neutering and releasing them. If they're hoping that by objecting to the TNR program that all the cats being trapped will be euthanized instead, they need to realize:
- It's not going to happen as long as volunteer "rescue" groups are in charge of the program. These groups aren't going to trap and kill.
- The city is unlikely to do it either, and there's a cost to having city personnel catch the cats and take them somewhere to be euthanized.
- Most importantly, culling has been shown time and time again to be an ineffective way to control feral animal populations. What's needed is a combined approach that includes measures such as neutering and vaccination, education to reduce the risk of human and domestic animal exposure to feral animals, and taking steps to discourage feral animals from spending time in close proximity to people and domestic animals.
Amaya states that "her" feral cat is a nuisance and she doesn't want it on her property. So what is she trying to accomplish? If anything, her actions will just help her single stray cat turn into a large extended family of stray cats that are susceptible to rabies.
There are certainly concerns with feral cats and TNR programs. They are not perfect and not always run well. Some people are opposed to them for various reasons, some of which are quite reasonable. It's a tough issue because one person's idea of success might be completely different from someone else's. Some people focus on the number of animals, while others focus on the quality of life of the animals, public health aspects, impacts of feral cats on wild bird populations and other diverse areas. A local council isn't going to be able to solve these problems, and it really comes down to an assessment of the potential usefulness of the program and the ability of the people involved to do it safely, ethically and legally.
Personally, I'd rather see well-designed, well-run and regularly-evaluated programs to try to reduce feral cat (and dog) populations, and (perhaps more importantly) increased vaccination coverage in the feral animal population, than nothing. Feral animals aren't going to disappear if we ignore them.
Image source: www.shadowcats.net
It's not like we needed any evidence that rabies is still an active, deadly disease, but a recent ProMed-mail posting contains 16 different rabies notices. They include:
- An animal control worker who was bitten by a rabid, stray cat that was trapped by a person in Texas.
- Rabies exposure in an unvaccinated dog in Maryland, that resulted in euthanasia of the dog because the owners didn't want to undertake the required 6 month quarantine for exposed, unvaccinated dogs. The dog was exposed to rabies virus while killing a raccoon.
- Diagnosis of rabies in two trapped raccoons in New Jersey.
- Rabies exposure in an Arizona woman who was attacked by a rabid fox while in her yard.
- More marauding (presumably rabid) foxes attacking people and dogs in Maine and South Carolina.
- Rabid bats and skunks in Colorado.
- A rabid fox in Alabama.
- Rabid raccoons in Virginia.
- A rabid raccoon attacking a vaccinated dog.
- Rabies exposure in people bitten or scratched by rabid stray kittens in New Jersey, Nebraska and Georgia.
Common themes or take home messages:
- Rabies is here (in most areas, at least) and it's unfortunately not going away any time soon. We can reduce the number of affected animals and decrease the risk of exposure of people and domestic animals, however, with good prevention strategies.
- Vaccination of pets is a cheap and effective way of protecting them, and anyone they are in contact with.
- Keep pets away from wildlife.
- If you are bitten by a wild animal, you must consider it a potential rabies exposure unless the animal can be proven not to have rabies.
- If you see an animal that is acting strangely, stay away and call animal control.
Bali's rabies outbreak continues to claim lives, largely because of inadequate access to proper healthcare. The death toll from this outbreak, which has been ongoing for about two years, is officially 58, although the true count may be higher.
The latest case was a 57-year-old temple priest who was infected after trying to break up a fight between strays dogs and his puppy. He was bitten by a stray dog in the process, but did not receive any post-exposure rabies vaccination because of a vaccine shortage. Rabies is basically 100% preventable when proper care is provided after an exposure, but inadequate access to proper treatment remains a problem, particularly in certain areas and in less developed countries. The priest started to develop signs of rabies about two months after the bite, which is a pretty typical time frame. Once signs of rabies are present, it's almost invariably fatal, and he unfortunately succumbed to the disease shortly after being hospitalized.
Despite ongoing efforts to control this outbreak, rabies remains a serious problem in Bali, and many stray dogs remain unvaccinated. Inadequate education of the public is a problem since not everyone who is bitten goes to a doctor, especially for minor bites. However, even if people go to a doctor, the shortage of rabies vaccine is a huge problem. This whole situation is clearly not under control.
Visitors to Bali need to be aware of this ongoing outbreak. If you are traveling to Bali:
- Avoid contact with stray dogs. You never know who's rabid.
- If you are bitten, promptly clean the wound and get to a physician.
- If you are bitten by a stray, make sure you get post-exposure treatment: a shot of anti-rabies-antibody and 4 (previously 5) rounds of vaccine over a few weeks. If you can't get the treatment started in Bali, get it as soon as possible. Rabies exposure is not an emergency, but you don't want to unnecessarily delay treatment. You don't need to be immediately evacuated from the country to a place you can be treated, but at the same time, you don't want to take your time, travel for a while, then get vaccinated a week or two later. You'd probably be fine, but rabies is not something with which to take chances. The incubation period is variable and the rapidity of onset depends in part on the severity and location of the bite. In particular, a severe bite to the head or neck region would be an indication for very prompt treatment. So, if you're bitten, don't panic, but try to get back home and get treated as soon as is reasonably possible.
Rabies vaccination of people planning on visiting Bali is not recommended, unless you are planning on having contact with dogs. If you are going to Bali to take part in stray dog vaccination, then rabies vaccination would absolutely be indicated. Otherwise, it's not really something that's needed. If you don't get bitten, you won't get exposed, and a little common sense goes a long way toward avoiding dog bites.
Recently, I was speaking with a physician who mentioned that a colleague has recommended that people with raccoons in their yard get rid of their dogs because of the risk of Baylisascaris procyonis. This parasite, also known as the raccoon roundworm, can cause severe neurological disease in people that ingest infective parasite eggs from the environment.
The most severe type of disease caused by the migrating larvae of this roundworm (neural larval migrans) is very nasty, and usually causes death or serious, severe neurological deficits. However, the recommendation to get rid of dogs when there are raccoons around makes no sense. Here's why:
- The main host for Baylisascaris is the raccoon. A large percentage of healthy raccoons (over 90% in some areas) are infected and pass large numbers of parasite eggs in their stool. Exposure to eggs from raccoon feces is the main source of human infection.
- Human infections are very rare. They predominantly occur in people that are at increased risk of ingesting feces or dirt, based on their age or behaviour.
- Dogs can be infected with Baylisascaris, but this is rare.
- The small number of dogs that are shedding Baylisascaris in their feces do not pose an immediate risk to people. Eggs that are passed in feces are not immediately infective. Eggs must mature in the environment (which usually takes 2-4 weeks) before they are able to cause infections.
- There are no clearly documented cases of dogs being a source of human infection.
- The main risk from dogs is probably the potential for dogs to carry old (i.e. infectious) Baylisascaris eggs into houses on their haircoats, after roaming around raccoon infested areas.
How do you reduce the already very low risk associated with Baylisascaris and dogs?
- Discourage raccoons from living near your house. Raccoons defecate in certain areas or "latrines," where the soil becomes heavily contaminated with raccoon feces, and where tremendous numbers of infectious eggs can be present. If you make your yard uninviting to raccoons, then they won't establish a latrine near your house.
- Carefully clean any raccoon latrines that might be on your property.
- Don't let you dog have contact with raccoon latrines.
- If your dog has had contact with a raccoon latrine, give it a bath. Baylisascaris eggs are sticky and can stick to the dog's coat quite well, so a thorough bath is much better than a quick rinse or brush. Wear gloves and some form of protective outwear (e.g. a coat that you take off after and promptly launder) while bathing the dog. Wash your hands thoroughly when done.
- Closely supervise people at increased risk of ingesting feces or dirt (e.g. young children) when they're outside.
- A routine deworming program will eliminate Baylisascaris in the intestinal tract of a pet dog, in the unlikely event it's been infected.
- Prophylactic treatment of dogs that have eaten (or have a tendency to eat) raccoon feces could be considered, but the need and usefulness of this is not clear.
Bottom line: You don't need to get rid of your dog if there are raccoons in your yard. The risk of Baylisascaris infection from your dog is extremely low, and the steps above can help you decrease the risk even further. Getting rid of the raccoons (instead of the dog) will be much more effective.
More information about Baylisascaris and neural larval migrans is available in our archives.
Today is World Hand Hygiene Day, an occasion being promoted by the World Health Organization’s (WHO) “SAVE LIVES: Clean Your Hands” campaign. This WHO initiative is aimed primarily at improving hand hygiene in healthcare facilities around the world, in order to help reduce healthcare-associated infections (HAIs) (e.g. infections that people develop while in hospital). Also to mark World Hand Hygiene Day, the CDC has launched its new hand hygiene website, which has tons of information on hand hygiene basics, guidelines, resources for promotional campaigns, and information for patients.
Hand hygiene is one of the most important aspects of controlling infection in human hospitals, but that’s certainly not the only place where it can be beneficial. It is also very important in veterinary hospitals, to help prevent the spread of infection between animals, whether they’re sick or they’ve just had surgery. Here on the Worms & Germs blog, we also talk a lot about using proper hand hygiene to help prevent the spread of zoonotic pathogens from pets to people. Even at home, just like in hospitals, our hands are one of the most common ways bacteria and viruses move from one surface to another, from one person to another, and from just about anything into our mouths (either directly or via our food). Dirt on your hands is easy to see, and it makes it easy to remember to wash your hands. The bigger concern is the microscopic amounts of dirt and germs on your hands that you can’t see, and the best way to take care of that is really to make hand hygiene part of your routine. Make it something that just naturally goes along with playing with your pet, or cleaning the cat’s litterbox, or poop-scooping after your dog. Although most of the time it may not be a matter of saving lives, it’s certainly a matter of saving people from being sick. Make hand hygiene a habit, and don’t just do it for yourself – do it for all the people (and pets!) you live with and interact with everyday.
Recent reports of a woman in Texas that "contracted rabies" are great examples of less-than-careful reporting. The headlines look dramatic, and a couple of articles state that a woman bitten by a puppy "contracted rabies", but it's far from the truth.
Here's the real story, as far as I can tell:
- A litter of stray puppies was taken to a shelter and then sent to a foster home.
- The woman who took them in was bitten in the leg.
- She received medical care and took the puppy to a vet. The vet euthanized the animal because of the aggression it was displaying and had it tested for rabies.
- The puppy was positive for rabies and the woman is undergoing post-exposure treatment.
It's not a nice situation for the person that was bitten, but it's not exactly a rare event and post-exposure treatment for rabies, when given properly, pretty much has a 100% prevention rate.
Authorities are also trying to track down any people that may have had contact with the puppies before they were taken to the shelter, to determine if more people need post-exposure treatment.
Strangely, the other puppies are being isolated for 45 days, after which time they will be put up for adoption (assuming they don't develop signs of rabies). This doesn't make a lot of sense. Standard recommendations are that unvaccinated animals exposed to a rabid animal should be euthanized or quarantined for 6 months. The 6 month quarantine is in place because rabies can take a long time to develop after exposure. Since these puppies came in with the sick one, and it's almost certain there was no information about their vaccination history, they have to be considered exposed and unvaccinated. This is true even if they were vaccinated at the time of arrival because they could have been exposed before vaccination. Further, animals are not considered protected until 28 days after vaccination, and exposure within 28 days of the first shot is the same as exposure of an unvaccinated animal.
In this case, it was pretty easy to determine that the woman didn't have rabies in some, but not all of the articles. I particularly liked how one of the stories described how rabies "eats away at the brain," a description you wouldn't expect to see from a more mainstream source.
Presumably, the woman who was bitten will be left with nothing more than some bad memories and an increased awareness of rabies. Hopefully the shelter reviews its policies to determine whether this could have been prevented and whether other measures should be in place to reduce the risk to people who foster animals. At a minimum, this would include ensuring foster homes know about the risks, know to get the animal to a veterinarian if it begins to act strangely (as this woman did) and ensure that other pets in the household are properly vaccinated.
My parents adopted a cat from their local OSPCA shelter the other day. He's an adult cat (maybe named by now, but not at last report) and he came:
- vaccinated against the typical group of feline diseases
- dewormed with fenbendazole
- treated with metronidazole (an antibiotic - it wasn't clear whether this was because he had diarrhea at some point or was diagnosed with something, or whether it was just a routine practice)
- treated with Revolution for flea control
The one thing that's missing from the list is vaccinated against rabies, which I find amazing. Apparently, the cat was given everything they can give at the shelter without the need for a veterinarian. (Presumably the cat came in neutered, because that would hopefully fall under the "need a veterinarian to do it" category. Prescribing an antibiotic would also be something I'd hope would involve a veterinarian.)
Sending cats to new homes without vaccinating them for rabies is bad practice. Rabies is a rare but extremely serious disease. Vaccination is critical, safe and easy. The OSPCA website says that not all shelters vaccinate against rabies. Some shelters have veterinary staff in the facility, so rabies vaccination would be standard there. Other shelters work with local vets to do this, but that's not universal, apparently. I don't see why this isn't a mandatory policy for the OSPCA. Yes, there is a cost to it, but that should be a cost of doing business. Rabies vaccines aren't expensive and many vets would work with groups like this to keep the costs down. Adopting an animal from a shelter isn't cheap, and recovering the small added cost of the vaccine should be possible. I'm not sure whether it really is a question of cost, accessibility or simply not bothering. Getting a veterinarian involved also has benefits beyond just giving the vaccine. Potential health problems can be identified, including diseases that could be transmitted to people that adopt the animals.
It's true that lack of vaccination of adopted pets can be addressed by getting them vaccinated right after adoption. Any pet that has been adopted (or purchased, or otherwise obtained) should be promptly examined by a veterinarian to identify any potential problems, and to make sure the pet is on a proper preventive medicine program. Realistically though, not everyone does this. While you don't like to set policies according to the lowest common denominator, you need to for a deadly disease like rabies when the consequences to people and pets are so high. I find it hard to justify sending any animal out of a shelter without rabies vaccination.
Image source: www.ontariospca.ca
A canine distemper outbreak has been identified in raccoons, dogs, coyotes, foxes and skunks in Los Angeles County. Local residents are being reminded to vaccinate their dogs against distemper and report any suspected signs of distemper to their veterinarian. (Keeping their pets away from wildlife should also be recommended.)
Distemper is an infection caused by a virus which is related to the virus that causes measles in people. It can cause different types of disease in dogs, raccoons and some other wild mammals, but neurological disease is often present and can appear similar to rabies.
Canine distemper cannot be transmitted to people, but, in a roundabout way, distemper outbreaks can be a public health concern. This is because of the potential for rabies cases to be mistaken for (and dismissed as) distemper cases, leading to increased exposure of people to rabid animals.
Quite a few years ago, there was a cat with neurological problems under my parents front porch. It was a stray cat that had been in the neighbourhood for a while, and which sometimes interacted with people. When the local authorities were contacted, the response was "Don't worry, it probably has distemper." This was probably true, and since there was no known direct contact with people (something that is difficult to really know in a social stray) testing for rabies wasn't done. However, the concern is that rabies cases will be missed, or, more concerningly, human exposure to rabid animals will be missed because of the assumption that it's really distemper.
Understanding disease patterns in an area is important when determining the likelihood of a particular disease and the appropriate response to a sick animal. At the same time, you can't get complacent and assume that trends are absolute. With an almost invariably fatal disease like rabies, you have to be careful not to overlook the rare case amongst large number of other, similarly appearing diseases. If someone has contact with an animal suspected of having distemper, the potential for rabies exposure must not be forgotten.
Image source: http://weblogs.baltimoresun.com
A large rabies outbreak continues in Moscow. There were 257 rabies cases reported in the area in 2009 - ten times the number from previous years, and well above the very low numbers that occurred for a decade of so after an aggressive control program to control the post-World War II rabies epidemic. Control of that outbreak mainly involved shooting of potential rabies vectors: stray dogs, foxes and raccoon dogs.
Various more humane but still aggressive control measures are being considered to help control the current epidemic, including banning movement of pets to suburban cottages (probably better to just vaccinate the pets first), canceling a dog show (pretty low yield - better to vaccinate), and mass immunization of wild and domestic animals (the key approach).
An aggressive approach makes sense. Rabies is almost invariably fatal and large numbers of people who are exposed require post-exposure treatment every year. Local wildlife population patterns, wildlife rabies hotbeds and rates, pet numbers, pet movement and vaccination must all be considered when determining the best approach to control. Apparently, about 30 000 pet dogs visit cottages in the Moscow area each weekend, and there's concern that they could bring rabies back to the city with them. Authorities have warned about traffic jams that might develop, presumably from police stopping traffic looking for contraband canines. However, instead of banning dog movement, it would likely be more effective to increase vaccination (or even mandate it for dogs in those high risk regions) and control roaming dogs. If a dog doesn't roam freely in the country, it's less likely to encounter a rabid animal. If it's vaccinated, it's unlikely to get infected if it does get exposed. If it's not allowed to roam when it returns to the city, it's less likely to spread rabies to other animals and people in the very rare event that it was exposed and infected. Furthermore, if wildlife are vaccinated through rabies bait drops, the chances that a roaming dog will be exposed get even lower.
Ensuring the highest possible canine vaccination rates is the key measure. Whether that's through mandating vaccination, providing it at low cost, or making it more convenient for owners to get it done, it's a great place to focus efforts and resources. In principle, it's a simple concept. In practice, it can be more difficult, especially when compliance of the general public is required.
For those of you that want to practice your Russian reading skills, here's the original story.
Deworming has become a controversial subject. There are numerous opposing views, strong opinions and conflicts of interest that drive a lot of debate on the subject. There's no argument that parasites can be bad for pets and some can pose a risk to people. There's no argument that we want to reduce parasite burdens in pets to improve pet health and decrease human risks. It's the "how" that causes all of the problems. Developing deworming strategies requires consideration of a several different things, including:
- What parasites are in the area?
- Are the risks the same all year round or are they seasonal?
- What parasites pose a risk to an individual pet or what are the pet's chances of exposure? (e.g. Does the pet go outside? Is it exposed to many other animals? Are there multiple pets in the household?)
- Are there any people in the household at particular risk for parasitic infections? (e.g. young children, people with developmental disorders that might be more likely to be exposed to pet feces?)
Everyone agrees puppies and kittens need more aggressive deworming, but there are a few different approaches to managing deworming in adult animals.
The Companion Animal Parasite Council advocates monthly deworming for a few reasons. One is that, based on the duration of activity of the drugs used, monthly treatment prevents establishment of significant parasite populations in the animal (and therefore also in the animal's environment). It also keeps the treatment user-friendly - it makes it easier for people to remember to treat their pet. Some concerns with this approach include its "one plan fits all" mentality, despite the fact that there are great differences in the risks between different regions, and even between pets in the same area. There are also concerns about such heavy use contributing to the development of parasite drug resistance (which is a problem in some other species like horses and sheep), although this doesn't seem to be a major concern... at least not yet.
Recent European guidelines take a somewhat different approach and use a philosophy more geared towards individual risks for each animal. These guidelines recommend that if regular deworming is used, animals should be treated at least 4 times a year, with no more than 3 months between each treatment. This is based on some research indicating that dropping treatment to 3-4 times per year had no effect on parasite levels. This approach is therefore more conservative (in terms of the number of treatments) and probably has less of an impact on the development of resistance, but it requires more organization and thought. If used properly, it's probably a good approach.
Yet another approach was recommended by a Canadian Parasite Expert Panel. With their approach, in low-risk households (both pets at low risk for parasite exposure and people at low risk of infection), treatment is based on fecal examination results or, if fecal testing is not performed, once or twice yearly treatment is recommended. In high risk households, fecal testing is recommended 3-4 times per year, with treatment based on results, or administration of routine preventive treatment at least 2, and preferably 3-4 times per year. The main criticism of this approach is that it's more complicated and perhaps prone to errors or missed treatments.
There's no clear answer, nor should there be. There really can't be a "one program fits all" approach that properly addresses the risks for all pets (and people) in all regions. Tailoring the deworming strategy to your pet, based on your pet's and your family's risk, is the logical approach. Regardless of the chosen approach, regular fecal testing is a good (and underused) way to assess what's going on with parasites in your pet, and to identify treatment failure or the emergence of drug resistance.
Monthly heartworm prevention has an impact on what you do as well, since typical heartworm preventives are also effective against roundworms and hookworms, the main parasites targeted by routine deworming. If you are in a region where heartworm is present, monthly treatment during the heartworm season is indicated, and the main decision that needs to be made is what to do the rest of the year (where heartworm isn't a risk year-round).
Heartworm is an important problem in dogs. It's a parasitic disease caused by Dirofilaria immitis and is spread by mosquitoes. It can cause serious, even fatal disease, and routine testing and preventive medication is an important thing for dogs in areas where D. immitis is present. Dogs (wild and domestic) are the natural host for this parasite, but other species can be accidentally infected, including people and cats. People become infected by being bitten by a mosquito that is carrying the parasite, having acquired it from an infected dog. Human infections seem to be quite uncommon and, interestingly, while this is a serious problem in dogs, it tends to be rather innocuous in people. In fact, the biggest problem with heartworm infection in people is the fact that it can be confused with other, more serious problems, leading to invasive testing.
After infecting someone, D. immitis works its way to the blood vessels in the lungs. This can result in a small area of inflamed tissue in the area. If a chest x-ray is taken, a "coin lesion" (a small, usually 1-3 cm spot) is often present. The parasite infection usually doesn't cause any problems in people, but lung cancer and tuberculosis can look the same on x-rays. Usually, open-chest surgery ends up being performed to get a biopsy of the area because of the concerns about cancer. In heartworm cases,the biopsy identifies the problem as D. immitis, which is much better than cancer, but the risks associated with having undergone such an invasive procedure are much greater than that of the parasitic infection itself.
Typically, treatment is not recommended in people because the infection rarely causes problems and people are "dead end" hosts, meaning they cannot pass on the infection. (Unlike in dogs, infected people don't have the parasite microfilaria in their blood, which is how the infection is passed on to mosquitoes and other animals).
Heartworm is a rare and rather innocuous problem in humans - it's nothing to lose sleep about.
Image: A diagram of a very severe case of heartworm in a dog, in which there are so many worms in the pulmonary arteries that there is "back-up" of the parasites into the right side of the heart, which is how the parasite got its common name.
In response to an ongoing rabies outbreak, Thailand has launched a program to vaccinate stray dogs. A posting to ProMed questioned this approach.
"The authorities plan to catch stray dogs, to vaccinate them, and to release them. This is inadvisable, since rabies incubation in dogs may extend to a year, although it is mostly between 2-3 months. Catching an animal which might already be incubating an infection and then vaccinating it will not only not protect the animal but put at risk the lives of people led to believe that the animal is safe", wrote Maya Kimchi.
True, you could not guarantee that a dog that was caught was not incubating rabies, and in that case, vaccination of the dog would not be effective. However, the odds of this are very low, and it doesn't make sense to not vaccinate. The worst case scenario is you have a dog that develops rabies, that would have developed rabies anyway, but it is less likely to spread it to the other dogs you've vaccinated. There would be no risk to people vaccinating the dog since it wouldn't be infectious at that point.
"In an endemic country where there are many stray dogs and many cases of rabies in animals and humans, as in Thailand, the solution of [the problem] of stray dogs is to reduce their number and carry out mass vaccination to all owned dogs, cats, and ferrets."
The problem is the stray animals. Vaccination of pets is very much an important component, but vaccinating pets and ignoring the reservoir (stray dogs) doesn't help in the long run.
"If a country decides to avoid the elimination of stray dogs, it will be necessary to catch them, to vaccinate them, and to [quarantine] them for 6 months at a minimum, and only subsequently, together with birth control measures (castration/sterilization), release them for adoption, after registration in a database for further control."
Here's what the World Health Organization's Expert Consultation on Rabies says:
"Mass canine vaccination campaigns have been the most effective measure for controlling canine rabies."
"There is no evidence that removal of dogs alone has ever had a significant impact on dog population densities or the spread of rabies. The population turnover of dogs may be so high that even the highest recorded removal rates are easily compensated for by increased survival rates."
"Attempts to control dog populations through culling, without alteration o f habitat and resource availability, have generally been unsuccessful."
Culling is rarely the answer. Vaccination of stray and pet dogs, education of the public to avoid contact with stray dogs, controlling roaming of pet dogs to decrease control with strays, educating the public about the need for post-exposure prophylaxis if they have been bitten by a stray dog and ensuring that the healthcare system has the appropriate resources (e.g. available rabies antibody and vacccine) and knowledge to handle exposed individuals is the best approach.
The Toronto Star had a front page article today about an ongoing distemper outbreak in raccoons, and the potential effects on dogs. Toronto's not alone, as there are distemper outbreaks underway in many different municipal regions.
Distemper is an infection caused by a virus that is related to human measles virus. It mainly affects dogs, raccoons and ferrets. It can cause intestinal, respiratory and neurological disease, with neurological problems being the most severe. Vaccination of dogs against distemper is highly effective, and has greatly reduced the impact of this virus on the pet dog population.
Distemper cannot be transmitted to people, so the disease itself is only an animal health risk. However, there's an indirect effect of which people need to be aware. Rabies always needs to be considered in dogs and raccoons that have signs of neurological disease. If there is so much distemper in an area that people assume every sick (wild) animal they find has distemper, there is a risk that the odd (but important) case of rabies may be missed, leading to human exposure. It's easy to dismiss a neurological raccoon or unvaccinated dog as having distemper, and it usually is distemper (particular in light of the current outbreak), but the implications of missing a case of rabies can be severe since it can be transmitted to people and is almost invariably fatal.
If distemper is present in your area (or, really, even if it's not currently a problem):
- Make sure your dog is vaccinated.
- Keep your dog away from wild animals, especially ones that are acting strangely.
- Keep yourself away from wild animals, especially ones that are acting strangely.
- Don't do things that will encourage raccoons to move into your yard, like leaving out food.
- If you see a wild animal that is acting strangely, call your local animal control agency.
Photo credit: The Star - Toronto edition 18-Feb-10
In response to ongoing problems with rabies in raccoons in New York's Central Park, a vaccination program is now underway. Raccoons are being trapped, vaccinated, tagged and then released. This is a logical response to the outbreak and one that will hopefully have a significant impact.
Trap, vaccinate and release programs can help in a few different ways. Firstly, they protect the individual raccoons that are vaccinated. However, in the bigger picture, mass vaccination is designed to protect humans and animals beyond those that are vaccinated (this is referred to as "herd immunity" - click here for a good video about this concept from a previous post). As the number of vaccinated (and therefore immune) individuals in a population increases, there's less risk of ongoing transmission of the disease (in this case, rabies), since an infected animal is less likely to encounter a susceptible (unvaccinated) individual. If, on average, an infected individual does not have a chance to infect another individual, the outbreak will eventually die out. The key is getting a high enough percentage of the population vaccinated.
For eradication of dog rabies, the World Health Organization recommends vaccinating at least 70% of dogs in a population. I'm not sure what the critical number is for raccoons, but it's presumably a similar, and reasonably high, number. Since a high vaccination rate is needed, there needs to be a concerted effort to do more than just a token vaccination program. It also helps if there's good information about raccoon numbers and distribution in the area. As long as the Department of Health is serious about this program and puts the required time and resources into it, the odds are very good that it will be successful.
The medical journal Lancet has fully retracted the flawed 1998 study that raised a link between MMR (measles, mumps, rubella) vaccination and autism in children. This study fueled incredible debate and was a driving force in the anti-vaccination movement, and subsequent declines in vaccination rates were a key reason for the resurgence of measles. It also fostered general anti-vaccination sentiment that has continued to affect decisions regarding vaccination of people and animals.
The study has come under fire for years and has been highly controversial, with strong opinions on both sides. In 2004, the journal issued a partial retraction based on a conflict of interest of Dr. Wakefield's (the lead researcher), since it was revealed that he was being paid by lawyers acting for parents who believed their children had been harmed by MMR vaccination. The new full retraction goes much beyond this, and is based on problems that have been revealed with the scientific method, reporting of what was done, plus ethical issues pertaining to ethical committee approval.
The UK's General Medical Council ruled last week that Dr. Wakefield had shown "callous disregard" for the children involved in the study and acted "dishonestly." He faces being stripped of the right to practice medicine in the UK. Accordingly, all of the findings of this study are considered invalid.
Image source: http://www.dailymail.co.uk
Eight more rabid raccoons have been found in New York's Central Park over the past two weeks. These, plus the 12 rabid raccoons reported in the park last year, represent a major increase in disease frequency since only 1 rabid raccoon was identified in Central Park from 2003-2008. That's a concerning development given the number of people that visit this 843 acre park in the heart of New York city every day.
In response, the city's Health Department has started an education campaign to alert people to the risk, and tell people to stay away from wildlife, report any sick animals and to keep their dogs on leashes. Every pet owner also needs to make sure their dog's rabies vaccine status is up-to-date, even if they always keep their dog on a leash, because you never know what a rabid raccoon will do (such as attacking a leashed dog that walks by). There are also plans to vaccinate raccoons in and around the Park, however I couldn't find details about what type of vaccination program will be used.
Rabies has been diagnosed in a 6-week-old Jersey calf at a Maryland educational centre, raising concerns about exposure of farm visitors, particularly groups of school children. At least 70 kids and an unstated number other visitors had recently visited the farm.
Fortunately, the farm in question is not open to the public, so they should have an easier time identifying people who have been there (e.g. school groups). Contact tracing is underway to try to identify people that had contact with the calf. Simply petting the calf or being in the general area does not pose a risk. The main risk would be from contact of open wounds with the calf's saliva, or a bite. We don't typically associate bites and calves, but it can happen when calves are allowed to suck on someone's fingers - if the person sticks their hand in too far he/she may get chomped by the calf's sharp molars. Public health personnel are trying to identify people who had contact with the calf, then they'll determine whether there was a chance of exposure to the virus. People that were potentially exposed to rabies will undergo post-exposure prophylaxis, consisting of a shot of anti-rabies antibodies and four doses of vaccine over the course of a month. Not fun, but much better than getting this almost invariably fatal disease. At least nine students have started treatment so far.
Petting zoos and similar events are a concern in terms of disease transmission because of the large number of people that can be exposed to animals and the high percentage of children that are involved. Rabies is uncommon in petting zoo animals, but it is periodically identified at such a facility/event, often resulting in the need for post-exposure treatment of large numbers of people. Vaccination of petting zoo animals against rabies should be a standard practice. This calf, being only six weeks old, was too young to vaccinate, but if the calf's mother was vaccinated the risk of rabies would be lower (because the calf would get antibodies from the mother). There's no information about the cow's vaccination status or much else about the calf, apart from it being a recent acquisition.
The fact that a recently acquired young calf was allowed to have contact with the public is questionable management, because young calves are a high risk group for certain infectious agents like Cryptosporidium and Salmonella. The CDC recommends that children less than five years of age not have contact with young calves. Since young kids are frequent visitors of places like this, having calves (or at least letting people have direct contact with them) is quite questionable as well. Hopefully there will be a good review of vaccination, animal acquisition and animal contact protocols for this facility to reduce the risk of future exposures to rabies or other infectious diseases.
I received newsletter today from Intervet (a pharmaceutical company) that is targeted at equine veterinarians. One article discussed rabies in horses. It wasn't bad overall, but I thought the section on what to do when a horse might have been exposed to rabies was worth discussing.
The article asks, "If your client suspects that a horse has been bitten by a rabies-infected animal, what should be done?"
Answer: "Contacting you as the veterinarian is always the first step."
Great first step. A second step that wasn't mentioned should be, "Try to identify and (safely) capture the animal that bit the horse." This is often impossible but certainly worthwhile if it can be done. However, if you're trying to catch the offending animal, make sure you don't put yourself at risk of exposure to rabies in the process. If the animal can be caught, it's rabies status at the time of the bite can be determined (either through testing or quarantine). If it can be shown that the animal wasn't rabid, a lot of stress, hassle and expense can be saved.
"If the horse was previously vaccinated... Then isolate and observe the animal for 45 to 90 days (your clinical evaluation will involve gait analysis, radiography and a spinal tap)."
Boosting the rabies vaccine is also a good idea. The next step, however, needs to be contacting local regulatory officials to find out what you have to do. They determine if, how and how long an animal needs to be quarantined - this is NOT the decision of the local veterinarian nor the animal's owner. Most likely, they will recommend a 45 day quarantine for a vaccinated horse, since this is what is recommended in the NASPHV Compendium on Rabies. The discussion of diagnostic testing makes no sense. There is absolutely no indication to perform diagnostic tests on a horse that has been bitten by a rabies suspect. None. There are no tests that can be used to diagnose rabies in live horses (also exposed horses don't instantly develop signs of rabies). Horses should be monitored closely for signs of rabies during the quarantine period, but that's it.
"...and have the client make a list of all people who had contact with the horse."
This is often done when horses have or are suspected of having rabies, but not horses that are potentially exposed. It is done to help public health personnel contact people that may have been exposed to rabies. A horse that was just bitten by an animal is not a risk for transmission of rabies. (However, keeping a list of people who have contact with the horse after it's been bitten (i.e. durng the quarantine period) - which should be as short a list as possible - is a reasonable precaution in the unlikely event that the horse does develop rabies.)
"If the animal was not vaccinated, your options are to euthanize and perform a postmortem examination of the brain (the only way to definitely confirm rabies)..."
Euthanasia is one of the options that needs to be considered in an unvaccinated horse that has been exposed, which is one of the reasons that identifying the biting animal and testing it is critical, if it can be done. The last part of the above sentence (from the atricle) is complete nonsense. Why would you test the brain of a normal horse that has been euthanized because it's just been bitten by a potentially rabid animal? The horse isn't being euthanized because it has rabies, it's being euthanized because of the likelihood of it developing rabies weeks to months later. Testing of the brain will tell you absolutely nothing if the animal was only bitten recently.
"...or isolate and observe the horse for six months and develop the human contact list."
Again, this needs to be decided based on discussions with regulatory personnel who are responsible for dictating what is to be done. A six-month quarantine is a pretty standard recommendation for an unvaccinated animal. Creating a human contact list should not be necessary, since quarantine involves severely restricting contact of people with the horse and only a few (ideally one) person would have any type of contact.
The article wraps up with the very true emphasis on vaccinating horses. It's a cheap measure to prevent a relatively rare but invariably fatal disease.
This Worms & Germs blog entry was originally posted on equIDblog on 05-Jan-10.
.A Texas couple is undergoing rabies post-exposure prophylaxis after an abandoned puppy they adopted was diagnosed with rabies. They found the puppy outside and brought it into their house. One of them was subsequently bitten and they found out about the rabies diagnosis on Christmas eve.
One of the couple is quoted as saying "The doctor said 'It was a good thing they didn't wait until Monday, because it would have been too late. We couldn't have given you the shot because it wouldn't have done any good. You would have been dead within 48 hours." I really hope they completely misinterpreted what the doctor said, otherwise the doc has no clue about rabies. Prompt treatment is the goal, and you certainly don't want to wait any longer than you have to, however rabies doesn't kill in 48 hours, and you can start post-exposure treatment any time (just the sooner the better).
The couple also have seven other pets, who may also have been bitten. There wasn't any comment about what's happening to those pets. Hopefully they are properly vaccinated so they can be given a rabies vaccine booster and only undergo a short-term "quarantine" at home with the owners. (The alternative is immediate euthanasia or strict, long-term quarantine for months).
This isn't a new scenario - adopting a stray animal then finding out it has rabies. The less you know about an animal at the time of adoption, the greater the risks. I'm certainly not saying don't adopt a stray animal. But, if you are going to do it, recognize the risk, make sure you are in a low-risk household (everyone's susceptible to rabies, but some people are at greater risk for other zoonotic diseases and stray adoptions should be avoided by them), get the animal examined by a veterinarian as soon as possible, and make sure that it gets examined by a veterinarian if it develops any signs of disease.
All this leads into another another story I read a few days ago. Basically, it was a feel-good story about someone who found some puppies, stopped by a nursing home (or similar facility) and the facility adopted one or more of the puppies. This demonstrates some good points (e.g. resident's presumably had a great time watching the pups) and bad points (e.g. disease exposure, unknown temperament, injury risks from rambunctious puppies...) of animals in long-term care facilities. What if the puppies that were adopted by the home had rabies? It's happened before, and you end up having to administer post-exposure prophylaxis to a large number of people that already have enough health issues and risks. Nursing homes and other facilities should never adopt stray animals. Hopefully we don't see a news release in the next few weeks about widespread rabies exposure in that facility.
Video from wfaa.com
A rabies epidemic has been underway in Bali for some time. There have been 25 deaths, with 2 occurring in the past 2 weeks. There are several reasons for this ongoing problem: large numbers of dogs (especially feral dogs) with limited vaccination, rabies circulating in the feral dog population, inadequate post-exposure treatment of people, and poor education of the public regarding the risks of rabies and how to properly address dog bites.
An encouraging sign is the institution of a mass rabies vaccination program for dogs. Unfortunately it won't start until February, which is disappointing because some people may get infected and die in the interim, but there are likely considerable logistical challenges to overcome, making some delay unavoidable.
The goal of this program is vaccination of 70% of all dogs in each affected regency. According to the recommendations of the World Health Organization (WHO), 70% is the proportion of the canine population that needs to be vaccinated in order to have a chance of eradicating of canine rabies from a given area. It's a challenging goal given the number of feral dogs and the limited resources available in Bali, but it's critical to vaccinate as many dogs as possible. It is estimated that there are approximately 500 000 dogs on the island. Approximately 137 000 dogs have already been vaccinated and another 39 000 have been culled (destroyed). Vaccination will not be performed in two regions because rabies cases have not been identified there. (Hopefully they have good enough surveillance to be very sure that rabies truly isn't in the dogs in those areas. It's a bit of a gamble otherwise.)
One thing that has not been specified is how they intend to handle vaccination of feral dogs. It's not clear whether the numbers mentioned here include feral dogs and whether efforts are being directed at pet dogs only or both pets and feral dogs. Poor compliance with booster vaccinations was cited as a concern, implying this was only focused on pets. Achieving 70% vaccination of the pet population is an important step, but if there is still uncontrolled circulation of rabies in the large pool of feral dogs, eradication will not be possible. Hopefully, trap-vaccinate-and-release programs or oral rabies bating will be used to address the feral dogs.
Image: Mt. Agung, southern Bali
If an unvaccinated person is exposed to rabies (usually by a bite), they undergo post-exposure prophylaxis (PEP), consisting of an injection of anti-rabies antibodies and a series of 4 or 5 vaccines. (It used to be 5, but it was recently recommended to drop this to 4). This is a highly effective protocol which basically guarantees that the person won't get rabies IF the person is treated promptly.
If an unvaccinated pet is exposed to rabies, the situation is much different. The two options are euthanasia or a strict six month quarantine and a single dose of rabies vaccine either immediately or after 5 (of 6) months of quarantine.
So, if there is a post-exposure treatment for people that is basically 100% effective, why don't we do the same thing in dogs and cats?
There are a few possible explanations for this:
1) Rabies is almost invariably fatal. The significant public health risks take precedence over animal health and pet owner inconvenience, stress and pet loss.
2) There is limited information about PEP in dogs, and results have been mixed.
- In one study (Hanlon et al 2002), experimentally-infected dogs were treated with various protocols. Treatment with rabies antibodies on day 0, followed by vaccination on days 0, 3, 7, 14 and 35 was effective at preventing rabies in 5/5 dogs - a good result, but the small number of dogs tested (5) prevents us from drawing any broader definitive conclusions. Rabies antibodies alone protected 4/5 dogs. All dogs that did not receive the antibodies but were vaccinated on days 0, 3, 7, 14 and 35 died of rabies.
- In another study (Manickam et al 2008), all exposed dogs were protected by rabies vaccination on days 0, 3, 7, 14 and 28. A 3-dose regimen (days 0, 5 and 28) was protective with one vaccine but not another.
Clearly, based on the limited number and small size of these studies, and the differing results, we cannot recommend a canine PEP protocol with confidence. However, these studies strongly suggest that PEP can be effective in dogs, and I think we need to consider when and how to use it. I wouldn't necessarily use PEP to replace quarantine without more evidence (i.e. field studies). I think the use of PEP to help protect the dogs while maintaining quarantine to protect the public is a good start. If canine PEP can be shown to be as effective as PEP in people, then some day quarantine might not be needed.
Regardless, this situation highlights the need for current vaccination of all dogs and cats in rabies-endemic areas. If a vaccinated animal is exposed to rabies, there is no requirement for euthanasia or long, strict quarantine. Rather, standard guidelines recommend giving the pet a rabies vaccine (booster) and having the animal observed by their owner for a period of 45 days. Developing better PEP protocols for unvaccinated animals is useful, but I'd prefer to see it become a moot point as a result of high vaccination rates.
A large number of rabies cases in Santa Cruz County, Arizona has lead to the rare practice of implementing a county-wide rabies quarantine. Fifty-four cases of rabies have been diagnosed so far this year, mainly in skunks. That's about twice as many as normal.
Quarantine is probably not the best description of what they are doing, but they are taking measures to improve vaccination of pets, reduce roaming pets and discourage human-wildlife interaction.
For the next 60 days, the following rules are in place:
- Dogs and cats must be vaccinated against rabies.
- Dogs must be confined to the property or on a leash.
- People are not allowed to feed wild animals.
- Pet food must not be left outdoors after sundown.
Those are all pretty standard measures that should be used anytime. It sounds like these rules already exist in Santa Cruz County but their "quarantine" means that they will be aggressive in enforcing them. Increasing enforcement is a good idea, but ongoing efforts after this quarantine period are also needed because rabies will continue to be a risk in that area.
Image source: www.acmeanimalremoval.com
An article in an upcoming edition of Transplant Infectious Disease (Gisel et al) describes a case of Bordetella bronchiseptica pneumonia in a person who had received a kidney and pancreas transplant. This person had to board her dogs at a veterinary clinic while she was hospitalized for a bowel obstruction that occurred after surgery. The clinic required her dogs to be vaccinated against Bordetella bronchiseptica, a cause of canine "kennel cough." They were vaccinated intranasally (i.e. up the nose) with a modified live vaccine comprised of live B. bronchiseptica that is modified so it is unlikely to cause disease but can still induce a good immune response. The owner developed pneumonia after returning home and B. bronchiseptica was isolated. Specific testing was not performed to confirm that the vaccine strain caused disease, so it's possible that she was infected by the normal (i.e. "wild type") B. bronchiseptica (which still would have presumably come from the dogs).
Immunosuppressed individuals are at high risk for infection by microorganisms that usually don't cause disease in otherwise healthy people. Bordetella bronchiseptica is a good example of this. Care should be taken around pets by anyone whose immune system is compromised. Here are some recommendations pertaining to kennel cough vaccination:
- Immunosuppressed individuals should not receive modified live vaccines themselves, and it is probably prudent to extend this recommendation to avoid modified live vaccination of their pets with vaccines like the Bordetella (kennel cough) vaccine.
- If vaccination for kennel cough is required for entering a kennel or vet clinic, an exemption should be sought because of the potential risk to the immunocompromised person.
- If vaccination must be performed, injectable vaccination is preferred. It doesn't produce as good immunity in the dog compared with intranasal vaccination but the risks to the immunocompromised owner would be much less.
- If intranasal vaccination with modified live kennel cough vaccine is used, immunocompromised owners should not be in the same room during vaccination. They should avoid contact with the dog's mouth, nose and face for at least a few days after vaccination and should wash their hands (or use a hand sanitizer) regularly after contact with the dog.
- If respiratory disease develops in someone exposed to a dog recently vaccinated against kennel cough, the potential for vaccine-associated disease should be mentioned to the physician.
I heard this on the radio yesterday morning, I kid you not: Butterball has a "Turkey Talk" toll-free helpline, which naturally gets busy around turkey holidays like Thanksgiving and Christmas. Like many helplines, they get stories of every kind, and this year apparently one person called in and asked if it was alright that she thawed her frozen turkey in the bathtub - while her kids were in it taking a bath!
Anyone who has read anything about food safety hopefully knows that raw meat can potentially be (and usually is) contaminated with many different pathogens - that's the biggest reason why observing proper cooking times and temperatures is so important. Raw poultry in particular should basically be treated like it's contaminated with Salmonella and/or Campylobacter until proven otherwise. You can just imagine the field day that these bacteria could have in a nice warm, wet bathtub - it's just the way they like it, and it's exactly what we try to avoid in the kitchen, where food is ideally kept either nice and cold or nice and hot in order to prevent (or at least minimize) bacterial growth. Then of all things to put young children in this veritable cesspool of bacteria - turkey and all - it's just a gastrointestinal disaster waiting to happen. You also needs to consider what the turkey could become contaminated with sitting in bathwater. Even children who don't have diarrhea can be shedding intestinal pathogens - human pathogens which are obviously transmissible to other people. If you really cooked that bird well (maybe deep-fried it) I suppose that should ultimatley eliminate any surface contamination anyway, but I don't think I'd be able to get past the "ick" factor. Don't throw the baby out with the bathwater, but of there's a turkey in there (as far as I'm concerned) that can go.
I realize this is primarily a food safety issue, but it made me think about what else this person (or others) may put in a bathtub. In previous posts in which we've talked about reptiles kept as pets (all of which should be treated as Salmonella carriers), we've mentioned that ideally (if they need a bath) they should be bathed in their own designated container (like a big rubbermaid) and not in the bathtub. If there is no other option and the bathtub must be used, it should be thoroughly cleaned and properly disinfected (keeping contact-time with the disinfectant in mind) before it is used again by a person (especially children).
Ideally the same precautions should be taken if you bathe a dog in the bathtub, but the risks are not as high as with reptiles (unless the dog is very dirty, has skin lesions, or has (or recently had) diarrhea). We've talked about the limited risks of allowing dogs in backyard swimming pools (but of course there is even less chlorine in bath water). I hope no one ever bathes their dog with their kids - we could debate the risks, which likely aren't high anyway, but in the end the risk is simply unnecessary. The pool is one thing, but there's no reason for a dog to be in the tub at the same time as the kids (and really, how clean are the kids going to get with a dirty dog in the tub?). If you're trying to save water you can always throw the dog in after the kids are out.
If you're attempting to bathe a cat in the tub... well, based on most feline behaviour I'd say your primary risks are bites and scratches more than enteric bacteria and parasites. Proceed at your own risk!
A happy (and hopefully healthy) American Thanksgiving to all of our US readers!
European Antibiotic Awareness Day is an initiative of the European Centre for Disease Prevention and Control. This year it falls on November 18. The aim of the Day is to provide an annual opportunity for raising awareness about the threat to public health of antibiotic resistance and how to use antibiotics responsibly.
Responsible use of antibiotics can help stop resistant bacteria from developing and help keep antibiotics effective for the use of future generations. Successful national public awareness campaigns are already resulting in more rational use of antibiotics and a reduction in levels of antibiotic resistance in Europe.
Responsible use of antibiotics includes use in people and in animals. Here are some of the things you can do to help with regard to antibiotic use in your pets:
- Only give your pet antibiotics if directed to do so by your veterinarian.
- Make sure your pet gets the full dose of medication at the correct time(s) of day. If you are having problems getting your pet to swallow pills or take medication, contact your veterinarian as soon as possible. Your veterinarian may be able to give you advice on some "tricks" for getting your pet to take the medication, or sometimes the medication can be provided in a different form (e.g. a liquid instead of a pill).
- Always ensure your pet finishes the entire prescription. There should be no leftover pills or medication. Do not stop giving your pet the antibiotics just because it looks/acts like its feeling better. This is a common mistake that can have disasterous consequences! You should NEVER "save a few pills for the next time."
- Never give your pet antibiotics that were prescribed for you or any other person, whether they are expired or not.
Rabies baiting is a highly effective way to reduce rabies in wildlife populations. As we've discussed before, in Ontario this involves air-dropping edible rabies vaccine. These baits are dropped in key rural areas, but there is the potential for curious people to come into contact with the vaccine if they handle baits that they come across. It is recommended that people avoid contact with the baits and wash their hands if they do come into contact with one, because the baits contain a live virus. They do NOT contain live rabies virus. Rather, they contain a vaccinia virus that has been manufactured to produce immunity to rabies virus. The risk of human infection is low, but as we constantly get reminded with infectious diseases, low doesn't mean zero.
Today's MMWR reported a case of human vaccinia infection associated with a rabies bait. In August, a 35-year-old Pennsylvania woman was picking berries and her dog and found a rabies bait. The dog punctured the bait packaging and the woman subsequently handled the bait. It took around 30 minutes for the woman to reach somewhere she could wash her hands, which she then did. This person had a few factors that put her at higher risk of developing an infection, including some skin lesions on her hands from berry thorns, and she was on multiple immunosuppressive drugs.
The day after exposure, her doctor took blood samples for rabies and vaccinia virus antibodies and examined her hands. Skin lesions (papules, i.e. little bumps) developed three days later. These lesions were tested and vaccinia virus was found in them. The skin lesions progressed and she was hospitalized a couple of days later. She was treated with antibodies against vaccinia virus because of the progression of disease and her compromised immune system. She went on to develop muscle aches, headache and a swollen lymph node. She was treated with more antibodies and an experimental antiviral drug. She ultimately responded to treatment and was discharged from the hospital on day 19.
This is the second reported human infection associated with a rabies bait. Considering the millions of baits that have been dropped and the presumably relatively large number of people that have had some contact with the baits, the overall risk of disease is still very low. This person was at high risk because of her immunocompromised status, and it's likely that an otherwise healthy person would not have developed an infection like she did. The big problem here was her contact with the bait. She did everything right after that: washed her hands as soon as she could, called the Department of Health, went to her physician and ensured that testing was done, but she still got sick.
Avoid rabies baits. The risks are low but why take any risk? People that have compromised immune systems or skin diseases should take particular care. If you've been exposed to a rabies bait, wash your hands ASAP and contact the local health authorities to determine if anything else should be done.
A study in the Journal of the American Veterinary Medical Association (Murray et al 2009) investigated the rabies vaccination history of dogs and cats diagnosed with rabies in 21 US states between 1997 and 2001.
- 264 rabid dogs and 840 rabid cats were identified.
- 4.9% of rabid dogs and 2.6% of rabid cats had a history of rabies vaccination.
- Of the 13 dogs that had been vaccinated, only 2 were considered currently vaccinated. Similarly, of the 22 previously vaccinated cats, only 3 were currently vaccinated.
- Texas had the most positive dogs while Pennsylvania had the most positive cats.
This study cannot determine how effective vaccination is. You'd need to know the number of animals that were and were not vaccinated, and then the number that did or didn't get rabies to determine efficacy. The fact that a small number of properly vaccinated animals got rabies shows the vaccine is not 100% protective, which is not surprising.
Vaccination is an important part of rabies prevention, but it's not the only part. Vaccination is a last line of defense - avoiding exposure to rabies is the critical first line. To reduce the risk of rabies exposure, keep your pets under your control at all times. Keep bats out of the house and try to ensure that your house and yard are not welcoming to wild animals. Don't let your pets have contact with wildlife and pay close attention when strangely-acting wildlife are around. Active measures to reduce wildlife rabies such as rabies baiting are also important.
Don't assume because your pet is vaccinated that you don't have to worry about trying to reduce the risk of exposure to rabies.
Don't assume that an animal with neurological disease doesn't have rabies just because it's been vaccinated.
Herd immunity is an important infectious disease concept. Basically, it involves trying to ensure that a high enough percentage of a population is resistant to an infectious disease so that the disease cannot be spread easily through the group. Ensuring that a large percentage of the population is vaccinated helps protect individuals that cannot be vaccinated (because of allergy, disease or other reasons) or that did not properly respond to vaccination (not all vaccines protect all vaccinated individuals).
"Herd immunity" usually refers to this concept when applied to herds of animals, but the "herd" can be a small local population, a regional population, or broader, and it can be people or animals. For some human infectious diseases, it's been shown that vaccination of 75-95% of the population is required to prevent outbreaks. If vaccination rates start to slip, the chance of an outbreak increases. This is best seen in some areas where vaccination rates decline in certain groups of kids because parents are reluctant to have their children vaccinated (for one reason or another), and subsequently outbreaks of disease start occurring (or increasing).
Vaccination is an important (but not the only!) infection control tool. For diseases that are transmissible between dogs (or cats, people, or whatever other "herd" is being considered), vaccination of a single animal helps protect that individual from disease, and also helps protect the rest of the population.
During a public health infectious disease course that I teach, a student showed us a link to this interesting and amusing demonstration of herd immunity from the UK. Make sure you have your sound turned on. It's an entertaining description of the concept of herd immunity.
Norfolk, VIrginia's MyCityTalk.com has an article entitled "The Truth About Pet Vaccinations". It's basically the same as hundreds or thousands of other articles available on the internet purporting to try to set the unwary pet-owning public straight about pet vaccines. Here are some of the highlights.
The evidence against vaccinating, however, is overwhelming.
- What evidence? Someone's commentary? Sure, there are hundreds of those. Real scientific proof? Nope. No one is going to dispute that vaccine reactions and other problems can occur. That's clear. At the same time, vaccines clearly save lives and reduce illness. There is certainly a cost-benefit to consider, but non-evidence-based statements like this don't help. The risks and benefits do need to be considered when designing a vaccination program. Real evidence should be used, however.
It is more and more common to see cancer in dogs and cats under 5 years of age. Autoimmune diseases are on the rise as well.
- Maybe, although you have to be careful interpreting that. We have much better diagnostic tests now and can detect diseases we couldn't diagnose before. Also, animals that are alive because they didn't die of an infectious disease are able to develop these conditions. You cannot simply attribute such a trend to modern vaccine practices without looking at the other factors that may be involved.
Vaccinations do help prevent serious illnesses, but they should be used with restraint. Before vaccinating, consider the risk.
- Absolutely. Best piece of advice in the article.
If your cat is indoor only and will never be exposed to unvaccinated animals, the risk of infection is low.
- While the risk of exposure is LOWER for indoor cats, it's not zero. It's amazing how many "indoor" cats come into vet clinics after being hit by a car or getting into a fight with a wild animal. Indoor cats can escape. Also, other animals can get inside, particularly bats - a source of rabies exposure.
Request individual vaccines and vaccinate at least three weeks apart if possible.
- There's little to no evidence that using combination vaccines is a bad thing for your average pet. Also, individual vaccines aren't available for all diseases. Further, if you only vaccinate for one disease at a time and space them three weeks apart, it's going to take a longer time to have an animal with protective immunity. It makes it a lot more expensive too.
If your cats go outside and you have rabies in your area, give a rabies vaccine at six months of age.
- This sentence should start at "give." Every animal in an area where rabies may be present must be vaccinated, regardless of whether it goes outside.
Vaccinations do not need “boosting”
- Says who? This is a generalization that can cause problems. For some vaccines in some animals, a single dose may be adequate, but it's certainly not true for all. Some vaccines work better than others. Some diseases are more amenable to good vaccination prevention. Some vaccines are probably good for a long time, if not life-long. But not all of them.
Simple blood tests can determine if your companion’s antibody levels for parvovirus and distemper remain high enough to resist infection.
- Nope. You can determine antibody levels but no one really knows how to interpret them (i.e. what level means the animal will be protected). Antibodies are only one component of vaccine protection.
The currently licensed leptospira bacterins do not contain the serovars causing the majority of clinical leptospirosis today, so it is generally not a useful vaccine.
- That's true for certain areas. In some regions, the vaccines strains are protective for the strains causing disease.
Homeopathic Nosodes are an alternative some guardians are using when choosing not to vaccinate.
- There is no evidence whatsoever that nosodes do anything but make money for people who sell them.
They (nosodes) do not produce titers against these diseases like a vaccination.
- That's because they don't do anything.
Never vaccinate a sick or weakened animal.
- Good advice.
Educate yourself. Your veterinarian cannot make this decision for you, nor should they. You are your companion’s guardian. It is your responsibility to give them the best care you can by researching and carefully weighing your decisions about their healthcare.
- That's true. However, you need to make sure you get good advice from all sources. You should consult with your vet and feel free to ask any questions. You should also scrutinize information available on the internet. Vaccination recommendations have changed in recent years, with longer intervals between boosters, and they certainly may change further as we learn more. I'm perfectly happy stretching out vaccine intervals based on good data. My pets don't get vaccinated every year. The key is to base decisions and changes on evidence so that we maintain the effectiveness of this critical disease-prevention tool.
The original source of the article was actually the Healthy Pet Journal, an online "journal" (site) published by a holistic/naturopathic veterinarian (who of course runs a clinic specializing in such services). Always consider the source of what you're reading and the potential biases that come along with it.
In April, I wrote about an ongoing rabies outbreak in the popular tourist destination of Bali. Because of widespread rabies in stray dogs and fatal human infections, there were calls for the government to take aggressive action and for tourists to be aware of the risk. Apparently, things haven't improved much since then.
At least 9 people have died of rabies in Bali in slightly over a year. That's completely unacceptable for a preventable disease.
The latest victim (whose father-in-law died of rabies in August) was from an area that has not been officially declared as being part of the epidemic, so it has not received much government support. She was bitten by a stray dog in August. In any rabies-endemic area (even in the absence of an outbreak), that's clearly an indication for post-exposure treatment. However, she did not receive post-exposure treatment until 15 days after the bite, by which point it was obviously ineffective.
- Rabies post-exposure treatment must be started as soon as possible. If you wait until signs of rabies are present, death is almost certain.
- Be informed and be your own advocate. The family in this case may very well have pushed for post-exposure treatment, but it's critical to look out for yourself. If you have potentially been exposed to rabies, make sure you get treated.
- If you are going to Bali, don't be paranoid about rabies. Be smart. Avoid any contact with dogs (especially strays) and other wildlife. If you are bitten, get medical care immediately. If the animal isn't identified and quarantined for 10 days to make sure it doesn't have signs of rabies, you need post-exposure treatment. If you can't get it in Bali, get out and get to somewhere where you can be properly treated.
- If you are traveling to Bali (or any other rabies-endemic area) with the intention of working with wild or stray animals (especially dogs), get vaccinated before you go.
- More aggressive rabies control and education (including physician education) efforts are needed in Bali. Clearly, this outbreak is not under control and the fact that the latest death occurred in a new region suggests that this problem could be spreading.
More information about rabies can be found on the Worms & Germs Resources page.
In the wake of the death of Dr. Alister Rodgers from Hendra virus, there have been increasing calls for the Australian government to put significant resources into Hendra virus research. Various areas need to be investigated, including how this virus is maintained in the bat population, how it is transmitted from bats to horses, ways to treat infection and ways to prevent infection. Vaccination is an obvious topic, and creation of a vaccine appears to be possible. However, as I wrote the other day, there's a question about whether a company would put millions of dollars into development of a Hendra virus vaccine for people, given that the disease is very rare, is currently limited to one region, and only appears to be a risk for people in close contact with sick horses.
One thing that needs to be considered is whether it may be better to develop a vaccine for horses rather than people. Think about it:
- All reported human Hendra virus infections have come from people in close contact with sick horses.
- Human vaccines are very expensive to develop, test, get approved and market.
- Vaccines for animals are much cheaper to make because testing and regulatory requirements are not as strict. (This can lead to marketing of vaccines for animals with limited evidence of effectiveness, but the upside is that vaccines can get to market quicker and with less expense.)
- People are often more willing to get their horses vaccinated than to get vaccinated themselves.
So, even though it might sound strange, development of a Hendra virus vaccine for horses may be a more effective way to protect people.
If this approach is taken, a key step would be continued research into the epidemiology of Hendra virus infection to investigate other routes of human exposure. If people can get infected by other routes, vaccination of horses obviously wouldn't address the entire problem. However, based on what we know currently, vaccination of horses might be the most effective, timely and economic response to this pressing problem.
This Worms & Germs blog entry was originally posted on equIDblog on 04-Sep-09.
Rabies baiting is a common and effective way of controlling rabies in some wildlife populations, particularly skunks, raccoons and foxes. It involves dropping edible rabies vaccine, by airplane or by hand, into targeted areas. Millions of rabies baits are used across North America and baiting programs have been cited as a key aspect of wildlife rabies control. In one year, 1.3 million baits were dropped in targeted areas of Southern Ontario alone over a two-month period. A good series of pictures of rabies baiting is available here.
Rabies baits are usually a small rectangular block comprised of something that smells or tastes attractive to the targeted wildlife into which a liquid vaccine has been added. Some use fish meal and fish oil to attract wildlife. Others use combinations of fats, icing sugar, vegetable oil and artificial marshmallow flavour (don't ask me why - I'm certain there's a reason but I don't know if they've done taste-testing).
Often, the local public is notified in advance of the drops being made, and it is recommended that kids be closely supervised outdoors for a week or so to ensure they don't come into contact with the baits. It is also often recommended to keep pets indoors or on leash during the same period. (Pets are much more likely to be exposed to and to eat the vaccine than kids). It's also recommended that you wash your hands thoroughly if you have contact with a bait.
Rabies baits are quite safe, and these recommendations shouldn't cause concern. It's a case of being overly cautious. The baits are safe to touch, but it is still recommended that you don't touch them (if nothing else, they may make your hands smell pretty bad). Ingestion of a rabies bait by a person or pet is also unlikely to cause a problem. Any adverse affects are more likely to occur due to the non-vaccine component of the bait, particularly because of the typically high fat content. Ingestion of a lot of baits could certainly cause vomiting or diarrhea in a dog, just like ingestion of large amounts of other inappropriate foods.
Some groups recommend that you contact Poison Control if your pet has been exposed to a bait, but I'm not sure what they'd do in such a case. Other groups ask you to report to them that a pet ingested the bait, likely so they can consider exposure of people and pets when determining target areas for the next year. There's similar variation in recommendations if a person ingests the vaccine. Often it is recommended that public health be notified so they can record it, but it's very unlikely anything would be done.
On a related note, you cannot use rabies baits as a free way to vaccinate your pet. It might work, but there is no way to know, and if your pet is exposed, it would be considered unvaccinated if it was not properly vaccinated by a veterinarian with an appropriate dog/cat vaccine.
Clallam County (Washington) is considering dropping the requirement that pets be vaccinated against rabies in order to get a license. It's pretty clear that this is only based on a desire to get more people to pay for licenses. Sheriff Bill Benedict is quoted as saying "My view on this is, we're leaving money on the table by not finding a way to get more people buying licenses."
This money-driven mindset makes no sense, and raises the question "what is the purpose of licensing pet?" Is it only to provide a source of government income (in other words, a tax on pet ownership), or is it for greater purposes such as helping protect the pet and human population?
Another quote from Benedict: "You would still be required to have your pet vaccinated, but that would be more of an issue between the pet owner and the veterinarian." This isn't an issue solely between the pet owner and the veterinarian. Rabies vaccination is still required by law. Veterinarians do not have a mandate or power to require vaccination and enforce the law. With this "You still need have your pet vaccinated (wink, wink, nod, nod)" approach, the municipal government is essentially saying, "We really just want you to pay us for a license. We don't really care whether your pet is vaccinated against rabies or not as long as you give us money."
A local veterinarian wrote to the commission that "Licensing pets is sometimes the only reason an owner will get rabies vaccines... Rabies vaccinance is the law of the state, the law of the county. Licensing, in my view, is less important than vaccinating for rabies and may facilitate even more rabies cases."
Well said. The county may get more money because more people will get licenses, but it's certainly possible that fewer pets will get vaccinated. Just one rabies exposure could negate the increased revenue from more licenses based on the high costs of rabies post-exposure treatment (let alone the risk of disease, stress of exposure, costs required for investigating cases...). Since all those costs would come from other peoples' budgets, however, I doubt they're too concerned.
Benedict also stated "Most pet owners -- in fact the vast majority -- if they're responsible enough to get a license, they're responsible enough to get a pet vaccinated."
Good thing he's not a lawyer. It seems to me that he just shot his argument down. If the majority of pet owners that are responsible enough to get a license are also responsible enough to get a pet vaccinated, then why is this change required? An attempt to increase cashflow is not a good reason to change rules that are designed to protect the public and pets from a fatal disease.
A horse in Harford county Maryland has been euthanized because of rabies. The horse first starting showing signs of disease in mid-July, which manifested as "striking changes in behaviour." The report doesn't say when the horse died, but animals typically die within a few days of the onset of neurological disease. The horse was transferred to the New Bolton Center where rabies was diagnosed. Subsequent testing showed it was a raccoon rabies strain, although that does not mean that a raccoon was the actual source of infection.
Public health officials implemented a 45 day quarantine of the farm. Stray cats (about 25) were caught and euthanized. Fortunately, the family pets were properly vaccinated and have received booster shots (plus presumably a period of observation at home... a much better situation than if they were not vaccinated).
People that had contact with the horse have received rabies post-exposure treatment. This includes one person who had to be tracked down overseas.
Harford County Health Department spokesperson Bill Wiseman said "There was never a risk to public safety. This incident was a great example of public health work in action and cooperation between local, state and in this case, international authorities." I don't buy the statement that there was no risk to public health. While the risk of rabies transmission from infected horses is very low, it's not zero. Rabid horses have killed people because of their abnormal and sometimes aggressive behaviour. Further, the fact that this horse had rabies means that it got it from something. Rabies can have a long incubation period so it's not guaranteed that it acquired it on the farm, but you have to be prudent and assume that there is infected wildlife in the area that could pose a risk for other animals or people. Public health authorities managed the situation well and reduced the public health risks, but there were certainly still risks.
Rabies vaccination is highly effective. There is no statement about whether this horse was adequately vaccinated but it's unlikely. Proper vaccination would likely have prevented this horse's death, as well as the death of the stray animals, cost of vaccination of people, cost of veterinary care for this horse, quarantine of the farm and the associated financial and emotional costs. A dose of vaccine that costs a few dollars could have saved thousands of dollars and emotional stress.
Rabies is a rare disease in horses but its severity means it should not be ingored. Vaccinate your horses.
This Worms & Germs blog entry was originally posted on equIDblog on 14-Aug-09.
A recent press release from All Pet Naturals proclaims "First All Natural Organic Antibiotic for Pets Now Available."
I know that "organic" and "all natural" are big catch-words for some people, and may be mistakenly perceived as indicators of safety or quality. There are very good reasons why we used manufactured and tested pharmaceuticals. If I wanted an organic, all natural approach to antibiotic therapy, I could eat some moldy bread and hope that an antibiotic-producing yeast was present, hope that it was producing adequate levels of antibiotic to fight my infection, hope that the antibiotic would survive the acid environment of my stomach and be absorbed into my bloodstream, and hope that it would kill the bacterium that's making me sick. Doesn't sound like a good idea to me. Personally, if I need any antibiotic, I'd rather use one that has been shown to be effective, is produced using good manufacturing practices, can be taken at a known concentration and has good dosing recommendations, among other things. Playing around with unknowns in the face of a bacterial infection is not a good idea.
Back to the supposed "all natural organic antibiotic" product in question. It is a grape seed and grapefruit seed extract product. Those compounds have some biocidal activities, meaning they can have effects on some bacteria and viruses in laboratory tests. Evidence for its use for treatment of disease is less convincing, but some topical biocides may be useful adjunctive treatments for skin infections. The manufacturers claim that this product can be used to:
- Treat skin problems caused by bacteria, even basic cuts and wounds.
- Fight tooth decay and gum disease, prevent free-radical damage to the lens and retina of the eye, and even treat glaucoma by protecting collagen structures in the eye.
- Help relieve asthma and emphysema.
- Help to support brain function with daily use.
I have a general line when it comes to products like these: the more a product claims to cure, the less likely it's going to do anything. There's simply little to no evidence for these claims. (Making health claims like this for a nutraceutical is also illegal.) I hate seeing animals that have suffered because people used products like these instead of recommended antibiotic therapy.
Products like this are typically harmless (unless they are used instead of proper treatment and medications) but, if you need an antibiotic, use a real antibiotic. If there's no clear evidence of need, don't use anything. Any compound with activity against bacteria, whether it's a traditional pharmaceutical antibiotic, an organic alternative or a disinfectant, can exert pressure for development of further resistance. So, we only want to risk that if it's really necessary. It's another example of the need to think, read, critically assess and ask questions about potential treatments before jumping on "all natural organic" bandwagon.
New research provides more information on the debate about testing and treating of healthy dogs for Giardia. Two abstracts on the subject by researchers at Colorado State University were presented at the recent American College of Veterinary Internal Medicine conference.
In the first study (Clark et al), fecal samples were collected from 220 healthy dogs. Giardia was detected in 11.4% of samples, but no dogs carried assemblages (types) known to cause disease in people.
In the second study (Lappin et al), they evaluated whether treatment of healthy dogs that were shedding Giardia would eliminated the parasite. Sixteen infected dogs were treated with either fenbendazole or nitazoxanide. Eight (50%) of the dogs had to be removed from the study because of adverse effects from treatment! Of the dogs that completed the study, Giardia was still detected in 63% of dogs 34 days after treatment, indicating that the infection wasn't eliminated or that dogs were quickly re-infected.
These studies provide more support of the notion that there is no indication to test or treat healthy dogs for Giardia. Testing makes no sense when the parasite is so common but most infected dogs are healthy, and when strains carried by infected dogs are usually of no consequence to people. Giardia is essentially a normal part of the intestinal microflora in many healthy dogs. Treatment of healthy carriers isn't indicated because it can make dogs sick and because it doesn't work very well. Remember: above all do no harm.
The bottom line is don't bother testing healthy dogs for Giardia or treating healthy dogs in normal households.
In Canada, access to rabies vaccine for animals is restricted to veterinarians (i.e. only vets can buy the product itself and administer it to people's animals). In general, this is an excellent approach because it ensures that the vaccine has been handled and stored appropriately, animals have been vaccinated properly and accurate vaccination records are kept. I certainly wouldn't want rabies vaccine freely available, whereby anyone could buy vaccine, handle it poorly, vaccinate their animal improperly, and yet believe or claim to have a properly vaccinated pet.
The problem with this restriction is the fact that veterinary care is not always available. Specifically, I'm referring remote northern communities that do not have veterinary care on a regular or even a sporadic basis. I received an e-mail the other day from a medical professional in a fly-in First Nations community in Northern Ontario. They have not had a visit from a vet in a while, so the dogs there aren't vaccinated. Unfortunately, a dog was attacked by a wolf recently so it must be considered possibly exposed to rabies, resulting in euthanasia or long quarantine. The question was about what can be done in those communities to provide rabies vaccine for people's animals. I didn't know, so I inquired with the Canadian Food Inspection Agency, the federal agency in charge of all-things-rabies.
There are actually provisions in Canadian regulations for situations like this (a provision in the Health of Animals Regulations Section 132.4 (2), if you want to know specifically). This allows rabies vaccine to be sold in accordance with written permission granted by the Minister, in specific circumstances such as in a remote area where veterinary services are not readily available. The provincial veterinary association is typically contacted to determine whether or not there is a veterinarian who could arrange to do the vaccinations. If the provincial association agrees that there is no veterinary service available to the community, then permission can be granted to purchase vaccine.
It's quite a reasonable and logical approach that allows for access to rabies vaccine when needed, but has enough controls in place to ensure that this can't lead to abuse of the exception. People in remote communities in Canada should be aware of this. Some communities get periodic visits from vets but there are many others such as the one in this case that don't have any direct access to veterinary care, and this is a way of at least providing protection for people and pets against rabies.
Here's a question I received the other day:
"Do people who work with animals and who work in barns need a tetanus shot as a result of this type of work? We have Therapeutic Riding Programs in the region and there is a sense that perhaps the volunteers and those who frequently tend the horses need to receive this. Is this the case?"
Tetanus is a disease that we are quite concerned about in horses because horses are very susceptible to it. That's why we vaccinate them yearly. Tetanus can also affect people, but very rarely because of vaccination and because people have lower susceptibility to the disease. While we pay a lot of attention to tetanus in horses, this does not mean that being around horses increases a person's likelihood of exposure to tetanus. The bacterium that causes tetanus, Clostridium tetani, lives in soil and commonly present in the environment. The more environmental exposure that you have (especially to soil), the greater your risk of exposure to C. tetani. Being around horses doesn't increase your risk any more than doing other things outside.
Whether you have contact with horses or not should not change your approach towards tetanus prevention. You should be vaccinated against tetanus every 10 years. Many (probably most, actually) adults are not up-to-date on tetanus vaccination. Adults tend not to get booster shots on schedule, and often only receive them when they have had a wound that requires medical care. For example, If you get stitches, the medical staff will almost certainly inquire about your last tetanus shot, and give you another one if you haven't been vaccinated in the past 10 years (or if you can't remember).
More information about tetanus in horses is available on the equIDblog Resources page.
This Worms & Germs blog entry was originally posted on our sister site, equIDblog, on 10-Jul-09.
There have been a few press articles lately about the Companion Animal Parasite Council (CAPC)'s traveling roadshow on parasitic zoonoses. Measures to increase awareness about zoonotic diseases and encourage appropriate preventive measures are needed, and traveling shows such as this have the potential to reach wide audiences. However, it's important for people to critically assess everything they are told and understand the sources. CAPC produces some excellent educational material but, to my knowledge, it is fully funded by the pharmaceutical industry. That doesn't necessarily mean that CAPC's educational efforts are suspect - people participating with their roadshow have solid credentials, but you do have to critique some of the things CAPC says.
One news article about CAPC's efforts states that "The CDC reports that about 14 percent of the total U.S. population is currently infected with Toxocara, or internal roundworms, contracted from dogs and cats." I don't think that's accurate information. I believe that this is based on seroprevalence data, meaning 14 percent of the population has antibodies against Toxocara. The presence of antibodies means that at some point in life the person's (or animal's) body was exposed to Toxocara and produced antibodies. It does not mean that these people were ever sick and it certainly does not mean that these people are currently infected. Toxocara can cause serious infections and is a concern in some regions (although it's extremely rare in Ontario), so it warrants some attention, but we need to take a balanced and evidence-based approach.
One common theme in all of the reports that I've read lately is the statement that "The CAPC recommends that pet owners use preventive medicine year-round to control internal and external parasites for the life of their cat or dog, no matter where they live." There's simply no evidence supporting this broad of a statement. Risks in warm southern climates are not the same as in northern areas with cold winters. Prevalence rates of different parasites vary greatly between regions. There is no evidence supporting year-round deworming of dogs and cats in all regions. Statements like this weaken the other good educational information CAPC has, particularly when you consider their funding source.
Don't disregard educational materials from CAPC or other industry-sponsored groups, just don't accept them as gospel. Critically assess the information, and don't be afraid to ask for facts, or to get information from other sources.
For more information about deworming recommendations for dogs and cats in Canada, see this previous Worms & Germs post.
Two kids and one adult are undergoing post-exposure treatment for rabies after having contact with an infected kitten. One child saw the stray animal and went to give it some food, and he was bitten in the process. The kitten then proceeded to bite the boy's mother and another child in the neighbourhood. Fortunately, the kitten was taken to animal control and was identified as a rabies suspect. It was euthanized and testing of the brain confirmed it had rabies. Accordingly, the three bitten people are now undergoing post-exposure treatment. Animal control is handing out flyers in the neighbourhood to warn others, as there may be more rabid animals in the area. One particular concern with young kittens is that sometimes multiple animals from the litter are infected, so there may be more cute but deadly kittens in the area.
- Avoid contact with stray animals. That's the best way to avoid getting bitten by one.
- If you are bitten by a stray animal, the animal must be caught and quarantined. If you don't know the rabies status of an animal that has bitten you, you have to consider it rabid and get treated. If you are bitten by a stray or wild animal, call animal control to catch it. If you can safely contain it (e.g. lock it in a garage) without putting other people at risk, do so and then wait for animal control to capture the animal.
- Vaccinate your pets.
There are two situations when animals may be quarantined because of rabies concerns:
- After biting a person.
- After potentially being exposed to a rabid animal.
The time frame for quarantine in these two situations is quite different because of what the quarantine is meant to accomplish.
Animals that have bitten someone are quarantined for 10 days under observation to see if they develop signs of rabies. Most animals that bite do not have rabies, and this is the easiest way of determining whether the animal could have potentially transmitted rabies by way of the bite. If an animal was rabid and infectious at the time of biting, it would die from the disease within 10 days. Animals can only transmit rabies virus after it has reached the brain and started to spread outwards via nerves - it gets into saliva by working its way down nerves from the brain to the salivary glands. Once an animal gets to that stage of disease, they die quickly. So, if the animal is still alive after 10 days, it was not rabid at the time of the bite. Quarantine is important so that it can be clearly proven one way or the other whether the animal was rabid. If the biting animal was not quarantined and ran away, the recommendation would be to err on the side of caution and treat anyone bitten as if they'd been exposed... but we want to avoid that if at all possible.
The second type of quarantine (for a potentially exposed animal) is based on less solid evidence. The idea in these cases is to keep the potentially exposed animal isolated while waiting to see if it develops signs of rabies, because there is no other reliable test for rabies in a live animal. For example, if an unvaccinated dog gets into a fight with a rabid raccoon, it would be considered potentially exposed. It would be quarantined (or immediately euthanized... the other option) and monitored to see if it develops signs of rabies. The length of quarantine for non-vaccinated dogs is usually 6 months, but this may vary by region. This helps reduce further rabies transmission by ensuring that a dog that develops rabies during the quarantine period is not roaming at large and able to infect people or other animals. One weakness of this approach is the incubation period of rabies, which can be very long. There is not a lot of objective research on which to base the 6 month time frame (unlike the 10 day quarantine described above). After 6 months, it's very unlikely the dog will develop rabies, but we can never say it's 100% because of the rare cases of rabies in humans with extremely long incubation periods. In reality, it's likely that the vast majority of animals that are exposed will develop rabies before 6 months, so it's a reasonable time frame. Would it be better to use 4 or 8 months, or something else? Possibly, we just don't know.
The easiest ways to avoid hassles associated with rabies quarantine are:
- Prevent bites. If your pet is trained and observed properly, it's unlikely to bite anyone, so the 10-day post-bite quarantine shouldn't be an issue.
- Vaccinate your pet. Properly vaccinated pets are not subject to the same long, strict quarantine (although a shorter period of isolation (often at home) is usually still required).
More information about rabies can be found on the Worms & Germs Resources page.
A canine influenza virus vaccine has recently been released. Canine influenzais a virus that originated from a horse influenza strain and is now circulating in some dog populations. (To my knowledge, we have yet to find it in Ontario. We didn't find any evidence of it in an earlier surveillance study). It typically causes mild disease, as with influenza in people, but can also cause serious (including fatal) infections. These cases are most common in densely-populated, stressful environments like shelters and racing greyhound facilities.
Like most vaccines, this canine influenza vaccine does not claim to provide 100% protection. Veterinary vaccines can get conditional licensing and be marketed with little evidence of effectiveness. The manufacturers have produced data "supporting product purity, product safety under normal conditions of use in field safety trials and demonstration that the product has a reasonable expectation of efficacy." That means they have shown the vaccine is produced with good practices, had no obvious adverse effects in a safety study, and there is a possibility that it could be effective (presumably from showing vaccinated dogs produce antibodies against canine influenza virus). During the conditional licensing period, the manufacturers "will continue to submit data obtained in support of the product’s performance, which will be evaluated by government regulators to determine whether a regular product license may be issued."
There's a good likelihood the vaccine will be effective at reducing the incidence and severity of disease, as with influenza vaccines in other species. Basically, if a vaccinated dog gets exposed to the virus, it should be less likely to get sick, and if it gets sick, it should be less likely to have severe signs. Reducing the incidence and severity of influenza also has the benefit of reducing the chances of developing a secondary bacterial infection, which can cause very serious disease.
Deciding whether to vaccinate your dog largely comes down to the risk of exposure and the implications of your dog becoming ill. In an otherwise healthy dog that is not in a high risk environment (e.g. kennel, shelter, greyhound racetrack), it's questionable whether vaccination is needed. If canine influenza virus is in the area, it's something to consider, but the virus seems to be rare (or at least rarely identified) in pets in most regions. Discussing the risks and benefits with your veterinarian is the key.
Canine influenza is NOT considered a zoonotic disease. There is no evidence that it can infect humans. Therefore, there is no public health argument for vaccination.
Antibiotic resistance is a major problem. Anyone that denies that is delusional. Anyone who thinks that antibiotic use in veterinary AND human medicine don't contribute to resistance are similarly clueless.
Most people do understand these basic facts. However, what people feel should be done about the problem is quite variable, ranging from doing nothing to proposing strict bans on antibiotic use. More legislators are proposing strong restrictions on antibiotic use in agriculture, but little gets mentioned about use in companion animals and humans. A broad approach looking at all sectors, involving all available evidence, and looking at the potential impact of restrictions is needed. Restrictions that have so may loopholes that they don't curtail overall use are not helpful, nor are restrictions that are so severe that they result in increased illness in animals (which could then require more antibiotics and/or public health risks because of more zoonotic infections). I certainly don't have the answers. A concerted, broad-based effort is needed.
In an era where we have major concerns about antibiotic resistant bacteria and scrutiny of antibiotic use in veterinary and human medicine, it's completely ludicrous that you can walk into a farm supply store or pet shop in Canada and buy huge quantities of antibiotics, or order pretty much any antibiotic you want over the internet. Politicians like to talk about antibiotic overuse and restricting drug use in animals, but fail to take the simple step of making NO antibiotics available without a prescription from a physician or veterinarian. That wouldn't solve all our problems, but would be a great start! One case from my time in private practice stands out - it was a steer (a castrated male cow) with a broken leg. The farmer noticed that the animal wasn't using the leg and tried treating it with penicillin for a few days, which didn't fix anything (surprise, surprise). This certainly isn't an uncommon event. Many people treat their animals (farm animals and pets) with antibiotics without any guidance, often for problems that are not bacterial infections, and sometimes using inadequate dosing regimens (which further increase the risk of microbial resistance).
Taking the simple step of removing free access to antibiotics is easy and needs to be done. Controlling internet purchases is more difficult. One veterinary pharmacy website proudly states "We also have a wide variety of human grade antibiotics, none of which require a prescription!" This site has a wide selection of antibiotics for sale. Most are labeled for fish tank use, but the site mentions the human product names, and it's very clear these products are not really being sold for fish. These pharmacies are harder to control, but many are clearly located in countries like Canada and the US, and are blatantly breaking existing regulations. Take a look at the picture above... this human pharmacy is offering free Viagra, a prescription drug, with every order of levofloxacin, another prescription drug... all without a prescription from a physician. This isn't a matter of needing rules. It's a matter of simply enforcing them.
Antibiotic resistance is a complicated problem and simple measures aren't going to fix everything. However, if we don't even take simple steps, how are we ever going to take the bigger steps required to address this issue?
Currently, people that have potentially been exposed to rabies undergo post-exposure treatment consisting of one dose of rabies antibodies followed by a series of 5 vaccinations on days 0, 3, 7, 14 and 28. It's not fun but it's much better than the old horror stories of 14 or more injections in the abdomen, which was the standard until the 1970s. For most people, the series of 5 rabies vaccines is not that big of a deal, but some people have adverse reactions, and having to undergo that many shots is not enjoyable, especially for children.
Now, a US advisory committee has recommended changing the vaccine requirements to 4 doses. There are a couple reasons for this. One is that many people end up skipping the final dose anyway and none have ever come down with rabies (although the strength of this argument is dependent on how many of them were truly exposed and at real risk of disease). Another is the cost of vaccination, which runs $100-200 per dose. When you multiply that by the tens of thousands of people that are treated annually, eliminating a single dose results in pretty big cost savings.
However, it's interesting that this recommendation has been made without coordinating with vaccine makers. Therefore, if this change is adopted, physicians would have to choose between following the US recommendations or the vaccine label. This could lead to confusion as well as legal liability concerns. "Off-label" drug use is a touchy area, and is generally frowned upon. Vaccine manufacturers may be unwilling to change the label because of a lack of scientific evidence clearly indicating that 4 doses are effective, plus the fact that it would instantly reduce sales by 20%. If this guideline is adopted, significant education efforts, assessment of liability and discussions with manufacturers will be needed. If 4 shots are truly effective (which is probably the case) this is probably a good change.
More information about rabies can be found on the Worms & Germs Resources page.
At the same time that the country is drafting an animal welfare law that would ban widespread killing of dogs, a Chinese city has killed 36 000 stray and pet dogs in an effort to eliminate rabies. Since late May 2009, more than 6 000 people in Hanzhong have been bitten or scratched (presumably by dogs), and 12 have died of rabies. Certainly, this indicates multiple problems. One is the massive number of bites and scratches. Contributing factors probably include a large stray animal population, limited routine animal control efforts, and inadequate education of the public regarding bite avoidance. The number of injuries and deaths certainly indicates that an aggressive response is needed. However, there is little evidence that culls (i.e. mass killings of this type) have any effect on controling rabies and animal-associated injuries. Efforts are probably better directed at other forms of population control, vaccination of stray and pet dogs, and education of the public to keep stray dogs away and reduce the risk of bites. These types programs cost money, but the costs of treating 6 000 bites and 12 fatal rabies infections can be enormous. I don't know how many people received post-exposure treatment for rabies, or what such treatment costs in China, but it's estimated to cost about $1500 per person in North America. That would pay for a lot of rabies vaccine for dogs.
Photo: Hanzhong, China (source: www.panoramio.com)
A reader posed this question, with respect to having raccoons living around the house:
"One thing that causes me concern with the raccoon roundworm is the possible danger of infection to my pets and myself through the feces left behind from the raccoons in the yard and possibly in my vegetable garden. Can I acquire the roundworm from working in the soil and/or from my root vegetables etc? My cats mingle near the raccoons, they don't bother each other, should I get my cats tested?"
Certainly, working outside (particularly in soil) leads to the potential for exposure to many disease-causing agents, including Baylisascaris, as well as dog and cat roundworms (Toxocara spp.). Eating unwashed/uncooked vegetables is also a risk. However, in the grand scheme of things, the risks to the average person (not very young or very old, functional imune system) are minimal, especially if basic hygiene measures are used, such as washing hands after working in the garden, and thoroughly washing vegetables. Raccoons tend to defecate in the same specific areas most of the time (raccoon latrines), so in general gardens probably aren't common sites for raccoon feces, although it certainly can occur. Cats are probably more likely to defecate in gardens. We shouldn't take concerns about Baylisascaris lightly, because even though disease (larval migrans) is very rare, it can be very severe.
Now, about testing cats for Baylisascaris - there's not much use, for several reasons:
1) The likelihood of a positive result is very low. The prevalence of Baylisascaris in dogs is very low. Little is known about the prevalence in cats specifically, but it is presumably very uncommon there as well.
2) It can be difficult to differentiate Baylisascaris from the feline roundworm, Toxocara cati. Unless the lab has experience with this, they may not be able to tell the difference. Therefore, you might get a misleading result.
3) What does a positive test tell you? It tells you that the cat is shedding this parasite or that is has ingested eggs that are just passing through the intestine. The risk to people is still minimal if litterboxes are cleaned regularly. Contaminated stool is not infective until it has sat around for days to weeks, so regularly cleaning the litterbox and good handwashing can control the risk.
4) What does a negative test tell you? It tells you that the parasite was not detected on this single sample. It could have been there but not been identified. It might not be there today but could be there tomorrow (though this is still unlikely). A single negative test today does not tell you too much.
5) What would you do with the results? Probably not much. In the very unlikely chance that results were positive, it would likely be recommended to repeat testing to see if eggs are just passing through or whether the animal truly is infected with the parasite. That would determine whether treatment is needed. Otherwise, recommendations would be pretty much the same in both cases (good regular deworming program as directed by your veterinarian, proper handling of cat feces...).
The best way to prevent exposure of your cat to Baylisascaris (as well as other pathogens, predatory wildlife, vehicles, etc.) is to keep it inside.
A recent study from the Netherlands investigated the prevalence of zoonotic parasites in pet feces and on pets' haircoats. The authors sampled feces and fur from dogs and cats, and looked for Toxocara (roundworms), Toxoplasma, Giardia and Cryptosporidium. All these parasites are of concern from a public health standpoint because they can be found in healthy pets and can also infect people.
Toxocara eggs were found on the haircoats of 12% of dogs and 3.4% of cats. Levels were low, ranging from 1-31 eggs per sample. An important aspect of this study was that they also assessed viability of these eggs, and found that none were viable. Therefore, even though eggs were present, they were not relevant because they were dead. Exposure to UV light and lack of humiditiy were cited as possible reasons for the death of the eggs.
Toxocara were found in the feces of 4.4% of dogs and 4.6% of cats, which is consistent with other studies of healthy pets.
Toxoplasma was not found in the feces of any cat. (Cats are the hosts for this parasite so dogs weren't tested.)
Giardia was found in the feces of 15% of dogs and 13.6% of cats. However, when these strains were typed, the vast majority were species-specific types that do not cause disease in people. Only 2 of the 15 Giardia samples were assemblage A, a type that is transmissible from pets to people. This is very important to know because crude Giardia numbers don't tell you the whole story.
Cryptosporidium was found in feces of 8.7% of dogs and 4.6% of cats. However, they were not able to type these parasites to determine if they were species that typically cause infection in humans, or whether they were Cryptosporidium felis or C. canis, which rarely cause disease in people.
The discussion section of the paper contains an interesting and relevant point about exposure to Toxocara eggs on the haircoat of pets. The authors state "Even in the worst case scenario of highly contaminated fur, e.g. with the highest Toxocara [eggs per gram] of 300 and an embryonated rate of 4% from the study of Wolfe and Wright, it is necessary to ingest more than 4 grams of hair, with 12 embryonated eggs per gram, to ingest 50 infective eggs." Based on these data, exposure to parasites from the haircoat of pets is quite unlikely. It might be a greater concern with stray or debilitated animals, or with puppies/kittens, who could have much greater coat contamination.
The take home message: Normal contact with healthy pets likely poses minimal risk of transmission of zoonotic parasites. That being said, regularly washing your hands is still a good idea because of the potential for exposure to other types of microorganisms (e.g. bacteria), and in rare circumstances where there may be large parasite burdens on a pet. Good deworming practices, particularly for puppies and kittens, also need to be considered.
A comprehensive infection control document entitled "Infection Prevention and Control Best Practices for Small Animal Veterinary Clinics" was released last fall. A French translation has been completed and it now available on the Worms & Germs Resources page, as well as by clicking here.
This document is an excellent resource for small animal veterinary practices (in my completely biased opinion) and provides the most comprehensive description of infection control practices for small animal medicine. The field of veterinary hospital infection control is very much in its infancy, but guidelines such as this, combined with increasing interest and awareness by veterinary practitioners, will help increase routine infection control practices and hopefully reduce infectious disease transmission to patients, their owners and veterinary personnel.
- Parent finds a dead bat carried in by the family cat and, for reasons known only to him/her, puts it in a jar.
- The next day, the parent takes the bat to a school, takes it out of the jar, and presents it to 8 classrooms full of children. Many students, teachers and staff touch the bat.
- The school nurse finds out later that day (I assume this finding is accompanied by a large spike in the nurse's blood pressure), and advises the parent to submit the bat for rabies testing.
- The bat tests positive and an investigation is started.
- 107 students and staff are interviewed and all are identified as requiring rabies post-exposure treatment. One student reported that their finger may have been pricked while sticking it in the bat's mouth, which would be a high risk exposure.
- 74 people ended up being treated. There's no word as to why some declined.
This was clearly a completely avoidable situation that resulted in potential widespread exposure to rabies, a large investigation, stress for people and their families, as well as the expense and pain of multiple injections for many individuals - all because one well-meaning but poorly-informed parent brought a dead wild animal to school, and because none of the teachers or staff that witnessed this thought to act.
The school's insurance policy covered the $75 000 in vaccine costs (plus an additional $29 000 for vaccine that was ordered but not used by people who declined vaccination).
- People need to be more informed about diseases such as rabies. This type of information is available on the Worms & Germs Resources page.
- Schools need to develop and enforce policies regarding visitors and pets. Approximately 1/3 of large scale rabies exposures occur in schools.
- Common sense needs to be a little more common.
Canadian Guidelines for the Treatment of Parasites in Dogs and Cats have recently been released. These guidelines were developed by an expert panel, consisting of six Canadian veterinary parasitologists and two private practitioners. They provide a good, balanced approach to the treatment of parasites, with an emphasis on the risks present in different regions and in different types of pets. There is very little objective information on which to base some of the recommendations, so many aspects are instead based on expert opinion, not necessarily hard facts, but when data are lacking, that's when opinions from independent experts are most needed. The guidelines provide an overview of recommended treatments along with an explanation of the reasoning. This document is a useful resource for pet owners and veterinarians alike. There is also discussion about why guidelines in Canada differ from those in the US. To download these guidelines click here.
Note: Development of the guidelines was supported by a pharmaceutical company, but the information they contain was developed by the independent experts mentioned above.
The latest issue of Oprah's magazine "O" features the icon talking about her recent puppy dog adoption drama involving canine parvovirus. It just goes to show that even the pets of the biggest celebrities in the world are not beyond the reach of common microscopic infectious pathogens.
A couple of months back, Oprah adopted two cocker spaniel puppies from a shelter in Chicago. Unfortunately, within two weeks they both came down with parvovirus infection and had to be hospitalized. I'm sure both dogs received top-of-the-line care with no expense spared, but even so one of the puppies died. The other puppy came very close to dying as well, but happily she apparently has now recovered completely and is doing just fine (or quite likely better than fine, considering who her new owner is!).
Oprah also mentioned how one of her other dogs, Solomon, also suffered from a parvo infection years ago, but that dog was over a year old when he became ill. It's actually quite unusual for any dog to get parvo beyond one year of age - most adult dogs are not affected by the virus, unless perhaps their immune system is compromised for some reason.
These stories bring up a few interesting points to ponder:
It's great to adopt an animal from a shelter and give a homeless animal a home. It is an act of great kindness that I don't want to take anything away from in the least. However, it's important to realize that you never know what shelter dogs may be carrying, nor how well vaccinated they are.
- Even if the animals are vaccinated once at the shelter, the protective effect may be less than ideal if a properly timed vaccination series is not completed.
- In this case the pups may have been exposed to parvo after leaving the shelter, but they could have just as easily been exposed at the shelter, which begs the question of what else might they have been carrying? Bacterial pathogens such as Salmonella and Campylobacter are also particularly common in young dogs and cats (even healthy ones), and these are potentially zoonotic agents.
Young animals, particularly from shelters, are higher risk in terms of the infectious diseases they can carry and transmit. That doesn't mean they shouldn't be adopted, but it does mean taking some extra precautions for the first several weeks they're in their new home. These include being very diligent about controlling stool contamination of any kind (which can be easier said than done during the house-training phase), preventing contact with high-risk individuals (e.g. young children, the elderly, anyone with a weakened immune system) and lots of handwashing on the part of everyone involved with the puppy (or kitten!).
Parvo is a very serious disease in puppies, yet people sometimes become a little complacent about vaccinating for parvo and other puppyhood diseases. Remember, though, that the reason parvo has become so much less common than it used to be is largely because of widespread and effective vaccination. I have to wonder about how well vaccinated Oprah's dog Solomon was to get the disease at the age he did, but there could easily be other factors involved as well. The virus is still out there, and if we become lax in our infection control practices - including decreasing exposure of puppies to the stool of other dogs, as well as vaccination - it's waiting in the wings for its opportunity to move in. Even with the very best care the infection can still be fatal.
It's also relevant to note that, as demonstrated by Solomon's case, just because parvo is very uncommon in adult dogs doesn't mean it's impossible for them to get it. It's important to always remain diligent.
Parvoviruses are quite species specific, so thankfully people cannot get parvovirus from dogs, but remember that puppies can get diarrhea from pathogens like Salmonella, which can be transmitted to people. There is also a human parvovirus which is the cause of Fifth disease. Just like the dog virus cannot infect people, the human virus cannot infect dogs.
Image source: http://omg.yahoo.com
The Worms & Germs blog has officially been active for one year, and look how far it’s come! Just last week we surpassed 100 000 unique hits since our launch. We now regularly have over 1000 unique hits on the site per day during the week, and the numbers are still growing. The current swine flu outbreak has emphasized once again the importance of zoonotic diseases in the world today, and the diminishing division between human and animal health. It's great that we're able to provide a reliable source of information about zoonotic infectious diseases to such a wide and diverse audience.
Everyone involved in Worms & Germs would like to take this opportunity to thank all the visitors who come to our site, and especially those who keep coming back for more! Please continue to help us spread the word about zoonotic disease control and safe, responsible pet ownership. Questions, comments and suggestions are always welcome! -Scott & Maureen
Quarantining animals that have potentially been exposed to rabies is a standard practice, but quarantining a whole town is new to me. Because of a large increase in rabies cases in the Flagstaff, Arizona area, a rabies quarantine was established on April 8th by the Coconino County Board of Supervisors. The quarantine requires all dogs and cats to be enclosed or secured on their owner's property. When off the property, animals must be on a leash that is no longer than six feet in length. All dogs and cats must be vaccinated, and low-cost rabies vaccine clinics have been held to help increase compliance with this requirement. Vaccination of wildlife using baits containing an oral form of rabies vaccine will also be performed. The quarantine also restricts feeding and interacting with wildlife. Also, people cannot leave pet food outside after sunset and all compost piles must be completely enclosed.
This is an aggressive approach to rabies control in an area experiencing a wildlife outbreak of the disease. They've implemented comprehensive but still quite practical measures that should help reduce the risk of exposure of domestic animals (and people) without a significant negative impact on pet owners. I've mentioned my concerns about rabies vaccine clinics in the past, but this is a situation where I think it's a good idea.
It's always hard to evaluate the effectiveness of outbreak measures, because you never know what would have happened if nothing had been done. Regardless, it will be interesting to see how well this quarantine works, both in terms of the number of new rabies cases they see and the response of citizens to these restrictions. It would be very useful if Coconino County personnel provide information about how things went when the quarantine is over - the information might be useful for management of future rabies outbreaks.
Rabies vaccination is supposed to be given at regular intervals - typically every 1 or 3 years, depending on the vaccine. Some people don't want to vaccinate their pets on a regular basis, but they may not understand all the implications of this decision. Often, people ask whether antibody levels (titres) can be checked to determine if repeated vaccination is necessary or if it can be delayed longer. However, rabies is covered by very straightforward government regulations in Canada (and presumably in many other regions). According to these regulations, checking vaccine titres is not considered an acceptable alternative to regular vaccination. Knowing this, here are two scenarios to consider:
1) Your pet bites someone.
After a pet bites anyone, it must be monitored for 10 days to ensure that it does not develop signs of rabies. It makes no difference whether the animal is vaccinated or not. However, if you do not have proof that your pet has been properly vaccinated, in Ontario, it is theoretically possible that you could be charged under the Health Protection and Promotion Act.
2) Your pet is exposed to a rabies suspect.
If your pet was vaccinated, you'd have two options. Most commonly, your pet would receive a booster vaccine and would be observed at home for 45 days. Alternatively, if you wanted to avoid a booster, you could take a blood sample to check the rabies titre. If a protective titre (>0.5 IU/ml) was present, there would be a 45 day observation period. If a protective titre was not present, the pet would be treated as unvaccinated.
If your pet was not vaccinated, it would be subject to a strict six-month quarantine or euthanasia.
If your was vaccinated at some point, but not vaccinated according to the vaccine manufacturer's guidelines (i.e. it didn't receive the appropriate 1 or 3 year booster), it would be considered unvaccinated, and be subject to the same 6 month quarantine. It would not matter if the rabies titres had been checked and a protective titre had been present in the past.
From this, it should be clear that there are serious implications of not vaccinating your pet, at least in Canada. There are some circumstances where you may be rightfully hesitant to vaccinate your pet, such as if your pet previously had a severe vaccine reaction. However, if you choose not to vaccinate, you must be aware of the implications of this decision. Neither a letter from your vet stating that vaccination would be risky nor annual rabies titre checks are going to be of any help at all because of the rules that are currently in place.
The British Columbia Centre for Disease Control (BCCDC) has changed its rabies exposure guidelines and gone against established protocols used elsewhere. Typically, anyone who has slept in a house where a bat was present at the same time is considered to have been exposed to rabies if the bat was rabid or the bat's rabies status is not known. This is because bats can bite people while they are sleeping and the bite wounds can be so small that someone may not even notice after they wake up. People who get rabies from a bat bite almost always die. Because of the severity of this disease, the general rule has been to err on the side of caution and consider anyone even possibly bitten by a bat as exposed to rabies.
Yes, rabies is a very rare disease in people in this part of the world... but you don't want to be the rare person that gets it. I understand that risk analysis may indicate that there is, overall, low risk from sleeping in the same house with a bat, and that almost all people that receive post-exposure treatment didn't actually need it. However, for a fatal disease with the potential for uncertain exposure in such a situation, I think this is important to err on the side of caution. It's always difficult to reconcile risk analysis data with human lives. The BCCDC estimates that this new policy will only result in one (1) additional rabies death every 675 years. That's not a lot, but how would you like to be that one person?
I hope this isn't a decision influenced by cost. Post-exposure treatment costs about $1500 per person, and they expect that this protocol will result in "hundreds" of fewer people receiving treatment. The treatment of all people sleeping in houses with bats actually costs a huge amount of money to prevent a small number of cases. However, what is the cost (financial and otherwise) of even a single case of rabies that could have been prevented? That's a lot harder to incorporate into a risk analysis. Personally, if I had a bat in the house overnight and my kids were potentially exposed (again!), I'd go for post-exposure treatment without any hesitation. Call me a paranoid parent if you will, but I'd sleep much better at night (for years, since the incubation period following exposure can be a long, long time).
The Cherokee Scout reported a story about a North Carolina man that was attacked by a rabid fox in his own home. It seems he was awakened one morning by scratching at the front door. Thinking it was his cat, he opened the door, only to be greeted by a rabid fox that bit "plumb through [his] big toe", rampaged around the house, then bit his other foot. He killed the fox using a mop handle (definitely self defence), and it tested positive for rabies (no surprise here!). This was the sixth confirmed case of rabies in the county since March 16, 2009, indicating that people in that area should be particularly cautious. Marshall Duggan, the man that was attacked, was treated for his bite wounds and is now undergoing rabies post-exposure treatment. The morals of the story are:
- Be wary of rabies, particularly when an outbreak is underway. Make sure, as in this case, that animals are tested if there has been potential exposure (e.g. a bite).
- Make sure your pets are vaccinated against rabies.
- Keep your cats indoors. Mr. Duggan is lucky his cat wasn't exposed to rabies or killed by the rabid fox.
- Don't trust foxes that knock on doors.
More information about rabies can be found on the Worms & Germs Resources page.
ProMed mail reports two more rabies fatalities in an ongoing outbreak in Bali, Indonesia. The first person was bitten by a stray dog, which always must be considered a potential rabies exposure, especially in an area where an outbreak is underway. He received one rabies shot but did not undergo the whole post-exposure series because of a fear of needles, and he died.
The second person was bitten by both a stray and a pet dog, another clear indication for post-exposure treatment. She refused treatment because of a fear of needles, and also died of rabies.
These were two completely preventable deaths. The decision to forgo treatment almost certainly cost these people their lives - rabies is preventable with appropriate and timely post-exposure treatment. These cases also highlight the need for proper education of the public when it comes to rabies, both in terms of avoiding strays and the need for prompt attention when there's potential exposure to the disease. I have no idea how forcefully medical or public health personnel explained the need for proper treatment. For people that want to decline treatment, aggressive and comprehensive education is needed. Ultimately, people are allowed to make bad decisions, but we need to make sure they at least make informed bad decisions.
There are various other concerning issues with this outbreak, particularly the government's response to it. Multiple sources have apparently advised the government that aggressive vaccination and halting of dog movement between the peninsula and the mainland could contain this outbreak. So far, this has not been done. Amazingly, importing rabies vaccine into Bali was illegal until December 2008, and it is still illegal to vaccinate dogs outside of the outbreak area! The cost of vaccination has been used as an excuse not to do so. Certainly, financial issues are important in developing countries. However, the estimated cost is only about $0.50 US per dog. When one considers that this area is highly dependent on the tourist industry, they need to consider this as an investment to maintain their economy. Would you like to spend your vacation in an area with an ongoing rabies outbreak?
A dog park was closed because of an attempt by a dog-owner to disinfect puddles. The woman was seen pouring a gallon of bleach into a mud puddle, sparking an investigation. The site was closed while city staff pumped out puddles. The woman told the person that witnessed and reported the incident that her dog had contracted the intestinal parasite Giardia in the park, and she was trying to sanitize the water. However, authorities believe it may in fact have been a malicious act (i.e. an attempt to poison the dogs using the park).
- Firstly, there's no way the woman could know that the park (let alone a specific puddle) was the source of her dog's infection. Giardia can be found in the environment and in the stool of a small percentage of healthy dogs (~7% in many studies).
- Secondly, pouring a toxic substance into the puddles in the park is obviously not an appropriate response. Bleach is a good disinfectant when it's used right, but disinfecting outdoor surfaces like this is essentially impossible. Organic debris (e.g. mud) will readily inactivate bleach, but the bleach could still make an animal sick if too much (too high a concentration) is swallowed, because it's very caustic.
- Thirdly, for this woman to take matters into her own hands like this without consulting someone who knows something about infectious diseases, and potentially exposing a lot of animals to high levels of bleach is irresponsible. If there was concern about the park as a source of infection, the appropriate response would have been to talk to city staff.
In reality, the risk to other dogs was probably pretty low. It’s pretty obvious when there's a lot of bleach somewhere (even just based on the smell), and in general dogs would probably be very reluctant to drink bleach-contaminated water.
One officer stated that he suspects the Giardia story was an excuse contrived by the woman when confronted by the passer-by who witnessed the bleaching incident. That’s certainly possible, but I’m surprised someone would come up with a specific excuse like Giardia. If the woman is found, that should be easy to figure out - the diagnosis would have to be in her dog's medical record. Police stated that the woman, if identified by the authorities, could potentially face animal cruelty charges. I think that’s pretty unlikely, considering what usually has to happen for someone to actually be charged and convicted of animal cruelty. I suspect this really was an overzealous response by someone who lacks common sense. There was no comment about whether the woman would be billed for the city staff time required to deal with the clean up - that might be a more effective deterrent to similar incidents in the future!
Parks are inherently a high-risk environment for exposure to infectious diseases. Whenever you mix large numbers of animals, especially in an area where they often pass stool, there is an increased risk of disease transmission. You have to accept that when going to a park. People should also ensure that they never take a sick animal to a park, promptly clean up stool, and may sure that their pet is on an appropriate vaccination and deworming program. Disinfection of a park will never be part of the infection control program.
More information about Giardia can be found on the Worms&Germs Resources page.
"Rabies is a neglected and severely under-reported zoonotic disease in developing countries, killing each year worldwide an estimated 50,000 to 60,000 people, mostly children with terrible suffering and a much higher number of animals... Eliminating rabies in dogs is the optimal control method for preventing spread of the disease."
They also say:
"Dog vaccination and stray dog population control are more efficient and cost effective that post bite treatment in humans."
As with many diseases, prevention is much more effective (and potentially cheaper) than treatment. As OIE Director General Dr. Bernard Vallat explains, "The cost of a post-bite treatment in humans is about twenty to one hundred times more costly than the vaccination of a dog. Currently with only 10% of the financial resources used worldwide to treat people after a dog bite Veterinary Services would be able to eradicate rabies in animals and thus stop almost all human cases."
I think that the sentiment is excellent; we need to focus on vaccination. However, the thought that we could eradicate rabies altogether seems a little optimistic and surprisingly naive. Eradication of a disease such as rabies that has multiple wildlife and stray animals as hosts is difficult, and bordering on impossible. Providing more money for vaccination is excellent, but one of the major problems with rabies control in developing countries is actually vaccinating the animals, even if lots of free vaccine is available. Dedicating personnel and logistical time and money for vaccinating dogs may not be high on the priority list in many countries with other major economic, social and healthcare system challenges. Catching and vaccinating all stray animals is not going to happen. Vaccinating as many animals as possible is important, along with stray animal population control, education of the public about bite avoidance, education of the public and healthcare personnel about bite treatment and prompt availability of adequate post-exposure treatment.
With a good medical and public health system and an informed population, rabies deaths could one day be few and far between. Emphasizing more money for vaccination in the absence of other efforts isn't addressing the big picture. In a perfect world, we'd be able to vaccinate all animals - unfortunately, our world is far from perfect, and while thinking about best-case scenarios is good, we need to focus on what is practical and achievable. That involves more money for vaccination, along with broader approaches by groups such as Vets Without Borders.
A large outbreak of rabies continues to have devastating effects in Angola, Africa. While rabies outbreaks are not uncommon in some parts of the world, the number of people affected in this outbreak is remarkable. A hospital in Luanda, the nation's capital, has diagnosed rabies in at least 93 children in the past 3 months. All have died. The main source of the disease in this case is Angola's large stray dog population. Stray dogs can transmit rabies to other dogs and people through bites. The poor socioeconomic status of the country increases the risk of outbreaks like this because:
- Vaccines are not readily available (for dogs or people)
- It is difficult to organize and fund vaccination programs for stray dogs
- It is difficult to educate the general population about how to avoid and manage rabies exposure
- The healthcare system is relatively limited
These problems, all related to a poor economy, create a "perfect storm" for a rabies outbreak. The shortage of human rabies vaccine and the high cost of post-exposure prophylaxis (PEP) makes it much more likely that people will actually develop signs of rabies after being exposed. The cost of PEP is more than the average Luanda family makes in a month.
Fortunately, the outbreak seems to be waning. However, without improvements in stray dog management (including vaccination) and access to adequate PEP, future outbreaks and problems are inevitable. It was reported that "adequate" supplies of canine rabies vaccine are now available. Hopefully, a concerted effort to vaccinate as many dogs as possible will reduce the rabies load in the canine population, thereby helping to decrease the risk to the people living in the area as well.
A search is on for a woman in Spring Hill, Florida who was attacked by a rabid cat while jogging. The cat apparently jumped on the woman's back without provocation while she was out for a jog. The cat was later caught and found to be rabid, but not until after it had attacked three more people and a dog. Since the cat has been confirmed as rabid, and it is certainly possible that it may have bitten the jogger during the attack, there is a real risk to the unknown woman of developing rabies.
The potential for rabies exposure should be considered following any bite from a mammal. If the animal is acting strangely (attacking joggers would certainly qualify) and it's rabies vaccination status is unknown, the concern is much greater. It's important to identify any animal that has bitten someone so it can be evaluated to deterimine whether there is a risk of rabies. This would include examining the animal for clinical signs of rabies, and checking its vaccination status. Being vaccinated against rabies doesn't guarantee the animal doesn't have rabies, but it makes it very unlikely. Depending on the degree of risk and the status of the animal, observation of the animal in the home, strict quarantine, or euthanasia and testing might be indicated.
This jogger probably needs to be treated for rabies exposure, unless a bite can be completely ruled-out. This post-exposure prophylaxis (PEP) consists of an injection of anti-rabies antibodies, followed by 5 doses of rabies vaccine given over 28 days. It's not fun, but it's nothing like the old PEP method that people often hear about, which involved many more injections given in the abdomen. It's a small price to pay to avoid an almost invariably fatal disease.
I read a press release today entitled "New Parasite Infection Killing Pet Dogs in Southern England". It's about the lungworm Angiostrongylus vasorum. The main reservoir for this parasite in England is the common red fox. Slugs and snails are involved in transmission of the worm as well. Infection of dogs most likely occurs through ingestion of the parasite from contaminated water or other environmental sources. The press release mentions a study that was released last year which reported an increase in the parasite in wild foxes. It mentions (without providing any data) that infections are occurring regularly dogs in some regions. This may well be true but brings to mind an important point I mentioned the other day (among others): know the source of information you are reading. I know I'm being a bit cynical, and it's possible that they have the well being of pets in mind, but the press release is from an online veterinary pharmacy, a company that obviously benefits from increased treatment of pets with dewormers.
This is made clear by their statement "Luckily there are a number of medicines available that can provide real and lasting protection from this nasty parasite. At www.vetscriptions.co.uk we recommend that all dog owners make it their business to find out about this disease and make sure that their dogs are fully protected."
Is lungworm a real and increasing threat in the UK? It's certainly possible. I don't dismiss the possibility at all.
Would I get concerned about it at this point? No. I'd look for objective information and ask my vet if there are any concerns in my particular area. Like the press release says, people should "make it their business to find out about this disease."
So what does this tell me? It reminds me that there are a lot of potential infectious disease threats out there that I need to pay attention to, but there are also a lot of people trying to make money at the same time. It could be that this company is being benevolent and honestly trying to make sure that pet owners are aware of the risks of lungworm. It's also possible they are taking advantage of a marginally relevant problem. Information like this is good for raising some questions, but getting advice from a non-biased source is critical.
Deworming adult cats and dogs is a rather controversial area at the moment. Balancing concerns about animal health, zoonotic disease transmission, drug resistance, compliance and cost is difficult. Risks vary between different regions/climates and there are no clear answers. One area that is much less controversial is deworming of kittens and puppies (less than 6 months of age), as there is general consensus that aggressive deworming is needed in these animals.This is because young animals are much more likely to harbour parasites. They are also more likely to contaminate the household environment during the litter/house training process and tend to have very close contact with people. The greatest concern tends to be about roundworms, since they are very common in dogs and cats (especially young ones) and zoonotic infections can occur (i.e. visceral and ocular larval migrans, similar to that caused by the raccoon roundworm, Baylisascaris procyonis).
Standard deworming guidelines are:
- Puppies should be dewormed at 2, 4, 6 and 8 weeks of age, then monthly until 6 months.
- Kittens should be dewormed at 3, 5, 7 and 9 weeks of age, then monthly until 6 months.
Further treatments depend on various factors, including the animal's lifestyle (risk of exposure), how common different parasites are in the region and perhaps whether there are high-risk people in the household. Your veterinarian can provide the best advice for your individual pet.
Another thing to remember is that not all parasites are killed by all dewormers. Specific deworming programs need to be set up to address different parasite risks.
More information about roundworms (and other parasites) in dogs and cats can be found on the website of the Companion Animal Parasite Council, an industry-funded organization.
Photo: A large mass of roundworms from the intestine of a heavily infected animal.
Rabies clinics are common in some areas. They are typically one or two day events where people can get their pets vaccinated against rabies at very low cost. The good aspect of these clinics is that some animals that get vaccinated there would not otherwise be vaccinated. The downside of rabies clinics is that they are not the same thing as a normal vaccine appointment with a veterinarian. Rabies clinics are usually "assembly line" vaccination - the goal is to get as many animals vaccinated as quickly and efficiently as possible. The animals are not given a physical examination and there is no discussion with owners about preventive medicine or other problems. Therefore, there is no opportunity to detect and address other health problems, which is (in my opinion) the most important aspect of routine vaccination appointments. There is also no opportunity for vaccination against other important diseases.
Rabies vaccine clinics can be beneficial in situations where some people are unable (or, unfortunately, unwilling) to pay for a normal veterinary examination and complete vaccination. Anything that increases the number of animals vaccinated against this devastating disease is useful. However, rabies clinics also can compromise the health of animals (and potentially their owners) if they are the only routine veterinary contact. They can also end up hurting owners financially in situations where early disease would have been detected and addressed during a regular vaccine appointment. Often, diseases are much more difficult and expensive to treat when they are identified later.
So, while it's obviously tempting to take the cheapest option available, if you can afford a regular veterinary appointment, don't use rabies vaccine clinics. It will be better for your pet and for you to have a regular vaccination appointment with a good physical examination and full consultation.
More information on rabies can be found on the Worms & Germs Resources page.
A park in Orange County, Florida has been closed because a dog with canine parvovirus was found in the park. Canine parvovirus is a potentially serious infection in dogs (mainly puppies) that can cause severe vomiting and diarrhea. In some cases, it can be fatal. Proper vaccination against parvovirus is critical for puppies. In Orange County, they have closed the park because of concerns about parvovirus transmission. The have also apparently "bleached the dog park".
Parvovirus can live for a very long time in the environment, however disinfecting an outdoor environment is not only impractical, it's impossible! We can disinfect clean, smooth surfaces like sealed ceramic floors and smooth countertops, but we can't disinfect outdoor environments with permeable, porous surfaces and abundant organic debris (dirt). Bleach is not active in the presence of organic debris, and porous surfaces allow bacteria and viruses to escape contact with disinfectants. So, while it's good to see that they are concerned about disease transmission, this particular aspect of their control efforts isn't going to be effective.
Parvovirus exposure is an ever-present risk in areas where multiple dogs congregate. The virus can be shed in the stool of even healthy-looking dogs. In this situation (like all others) the emphasis should be on keeping high-risk dogs (e.g. unvaccinated puppies) out of these areas, not closing the park altogether and attempting to disinfect it. Parvovirus vaccination is very effective, and properly vaccinated adult dogs are quite low risk. Prompt removal of stool by dog owners helps reduce the risk further by decreasing the risk of environmental contamination. Therefore, the three most important control measures are:
- Ensure puppies are properly vaccinated.
- Keep puppies out of areas visited by numerous dogs until they have been fully vaccinated.
- Scoop poop.
And since the focus of this site is zoonotic diseases, remember that canine parvovirus is not transmissible to people. Human parvovirus infection (Fifth disease) is caused by a completely different virus.
This post originally appeared on www.equIDblog.com, the sister site of Worms&Germs that covers topics on equine infectious diseases, on February 3, 2009.
New animal health products are released on a daily basis. A great deal of time, effort and money is usually spent to market these products - sometimes more than was put into developing them. As a consumer, it's important to think before you buy, especially with new products. Take a moment to consider whether a product is right for your animal, and whether the product's intended use and claims are reasonable. The biggest problems tend to occur with "alternative" or non-traditional products, which encompass a huge range of products that are aggressively marketed, with little to no research or testing to back them up. Here are some specific points to think about:
- Ask for research proving that the product works. "Data on file", anecdotes and other non-scientific sources are not adequate. Demand published research in peer-reviewed scientific journals. That means that the research has been independently scrutinized. Published data are not a guarantee that something will work, because some journals are not very strong and may publish weak research, but the lack published research altogether may indicate that research was not done, was not done right, or showed no benefit to using the product. Regardless of the type of product, there is no reason why proper research cannot be done to prove it is beneficial if it actually works.
- When looking at promotional literature, read it with a bit of skepticism. Think about whether or not what they say makes sense. A good general rule that I have is something that claims to cure all that ails you, probably cures nothing.
- If promotional materials do talk about research, check if they did a proper statistical analysis to really show that the product is better than the alternative. Showing a difference in numbers between two groups really mean nothing without proper analysis. For example, you could flip a coin 10 times and get 6 heads and 4 tails. Someone else may flip the coin 10 times and get 5 head and 5 tails. Clearly there's a difference in the numbers, but does it mean there's a difference in the ability of the two people to toss a head or a tail? Absolutely not.
- Don't get taken in by endorsements from "big names". More often than not, they're being paid for the promotion.
- Consult your veterinarian about new products. Be aware, however, that bad science is often marketed to vets as well and your veterinarian needs to be equally diligent.
At the end of the day, it's still "buyer beware". However, thinking about these basic points may help weed-out some particularly poor products. Additionally, and more importantly, increasing demands by consumers to see solid supportive research may be the only way to get companies to actually invest in testing and research to make sure their products work.
Most pharmaceutical products are dosed on the basis of weight (e.g. milligrams of drug per kilogram of body weight). That means an animal twice the size of another gets twice the dose.
Other drugs (mainly chemotherapeutic drugs, like those used for cancer treatment) are dosed based on body surface area (e.g. milligrams of drug per square metre of body surface). With this type of dosing, large individuals get more than small individuals, but the differences are not as great as with weight-based dosing.
Vaccines are a different story. They are administered based on the "antigenic dose" which is independent of body size. Therefore, the same dose is required for an adult Bullmastiff and a young Chihuahua. While it may be tempting to split doses of vaccine between several animals, especially small breeds (and initially this may seem logical (based on their small size) to those who do not realize how the dose is determined), this may result in ineffective vaccination. Trying to save money by splitting vaccine doses can end up costing money through increased risk of disease. Always give the full dose of vaccine as described on the label.
This post originally appeared (in modified form) on www.equIDblog.com on January 4, 2009.
I admit I was a little slow picking up this Christmas story, but it's still "entertaining" (for lack of a better word). I've never thought about it, but I guess there are certain risks associated with playing Santa for pet photos. I'm not one to take my pets for pictures with Santa, but many worthy groups raise funds this way. During one recent event, "Santa" was bitten by a less-than-cooperative feline named Benny, who apparently didn't appreciate being in the company of the dogs which had also come. To make things worse, Benny wasn't your average cat - he was a pixie-bob, a very large breed of cat that resembles the North American bobcat (but it is in fact an entirely domestic breed)(pictured at right, from NBC10). After the incident, Benny's owners apparently produced proof of rabies vaccination, and everyone seemed fine. Besides the rabies concern, cat bites are not necessarily innocuous and severe complications can occur. That's one aspect of the story which hopefully didn't develop.
My point in writing this is to reiterate (again) my frequent statement that people need to make sure that their pets are properly vaccinated, even those that stay indoors all the time. Indoor cats can still bite people that visit, they can be exposed to rabid bats, and they can (not infrequently) escape. In this incident, if the cat had not had proof of rabies vaccination, a long quarantine period or even euthanasia may have been required - certainly not what anyone expects from a Santa photo-op.
And... maybe it's not a good idea to take large cats into strange places surrounded by dogs and thrust them into the arms of a strange person...something to consider.
Life is not risk-free. We shouldn't stop doing beneficial things just because of potential (and rare) side-effects, particularly when the benefits in most cases far outweigh the risks.
A recent article in the Cleveland Examiner discussed feline distemper (panleukopenia) vaccination. The author related the story of a cat that apparently had a "bad" (undescribed) reaction to the vaccine, which is certainly possible. Adverse reactions to vaccines are rare, but they certainly can (and do) occur. It's important that we don't react excessively to these highly unfortunate reactions, and end up in a situation where more animals get sick and die from the disease because people get scared of vaccinating against it. (The increasing rates of measles in people in some areas, including serious outcomes, following ill-informed paranoia of an association between vaccination and autism is a great human example of that).
The author goes on to state:
"What should you do to guard your cat against feline distemper? Ask a holistic practitioner for nosodes instead of a vaccine serum." But there is no evidence whatsover that nosodes have any effect. A cat "vaccinated" with a nosode is an unvaccinated cat.
"The diluted formula is safe—it contains no live pathogens-- and effective." It's probably safe, but in no way effective.
"A cat who doesn’t mingle with other animals probably doesn’t need a vaccine against viruses." Bad advice. You'd be amazed by the number of 'indoor cats' that are taken to vet clinics after being hit by a car, getting in a fight with a stray cat, or similar non-indoor encounters. Close contact with strays can also occur through screen doors and windows. Then there's the issue of rabies exposure from bats in houses. Altogether, avoiding vaccination of indoor cats will probably get the majority of cats in more trouble, not less!
In 2008, the American Association of Equine Practitioners (AAEP) published updated vaccination guidelines for horses. One of the changes from the previous set of guidelines was the inclusion of rabies as a core vaccine (meaning every horse should receive it). There was lots of discussion about this at the recent AAEP Annual Convention in San Diego, CA.
Some veterinarians don't like the idea of vaccinating every horse against rabies. Just like veterinarians and owners of dogs and cats who are concerned about over-vaccination in these species, the same concerns exist in equine medicine. Equine rabies vaccines are not approved for use every three years like some canine and feline vaccines, so they still need to be given every year until someone can determine for how long a vaccinated horse is protected from infection. Furthermore, there has never been (to my knowledge) a case of human rabies due to transmission from a horse. These are all valid points, but there are also a lot of reasons why including rabies as a core vaccine for horses is very good idea:
- Rabies is a very deadly disease, in both animals and people. To some owners, their horse is every bit a part of their family as any dog or cat could be. To other owners, their horses represent a great investment, and part of their livelihood. Even if the risk of disease in horses is low, protecting them is safe and easy, so it just makes sense. As the saying goes, an ounce of prevention is worth a pound of cure, but when there is no cure and prevention is so simple... you do the math.
- Rabies vaccination is extremely effective in horses, producing an excellent immune response even with a single dose. It does not require complex adjuvants that some other vaccines need to stimulate the immune system, which also makes it less likely to cause an abnormal vaccine reaction.
- Rabies is not a seasonal disease like many of the respiratory viruses or insect-borne diseases (e.g. West Nile) for which horses are also typically vaccinated. Rabies boosters only need to be given once a year, so this can be done during a time of year when no other vaccines are required, if there are concerns about giving too many vaccines at once.
- Horses live outside and in barns. Most are far less supervised than dogs and cats, but even these animals are at risk of rabies exposure. A rabid animal could easily be "brave" enough to attack a horse, even though it normally wouldn't. Bats can also easily get into and out of many barns - you may never know one was there, and finding a bite mark from a bat on a horse would be like looking for a needle in a haystack, but that's all it takes to transmit the virus. So it makes sense to give your horse added protection by vaccinating it.
- Rabies in horses may not look like rabies at first. One of the most common early signs is actually colic. A rabid horse that looks like a colic may expose the people who are trying to look after it before they realize what the horse has. In other horses the signs may be recognized too late, like the rabid horse that was found at the Missouri State Fair earlier this year, that resulted in exposure of many people.
- While rabies transmission from horses to people has not been documented, rabid horses have killed people, particularly horses that develop the "furious" form of rabies, which can cause them to become very violent.
For more information on rabies, see our rabies archive or the information sheets available on the Worms & Germs Resources page. For more information on rabies in horses specifically, visit our sister site, www.equIDblog.com.
Back in the 1980s, Vietnamese Pot-Bellied Pigs were a popular fad pet. These stout little oinkers are still out there, though they're not quite as popular as they once were. Potbellied pigs are cute (at least to some people... to each their own!), supposedly quite smart, and can even be house trained/litter trained. As with any new pet though, it's very important to do your research before going hog-wild and getting yourself a pot-bellied pig. Talk to your veterinarian about what your pig will need in terms of medical care - vaccines, deworming, spay/neuter, hoof trimming, tusk trimming... Because they are uncommon pets, some veterinarians may not be comfortable treating a pig. Make sure you ask ahead of time so you know to which veterinarian(s) in your area you can (and will!) take your pig.
We recently received a question about vaccination of pot-bellied pigs. Just like dogs, in some areas pigs need to be licensed by the city, and certain vaccines are required in order to obtain a license. In this particular case, pigs are required to be vaccinated against rabies, swine erysipelas and leptospirosis. Regular visitors to this site are no doubt familiar with the issues around rabies and why it's important to vaccinate for this deadly disease. (More information about rabies is available on the Worms & Germs Resources page and in our archives.) Swine erysipelas is a systemic bacterial infection caused by Erysipelothrix rhusiopathia, which can rarely cause a skin infection known as erysipeloid in humans. This is not to be confused with human erysipelas, which is a skin infection caused by various species of Streptococcus (particularly Streptococcus pyogenes).
But the question was about leptospirosis vaccination in pot-bellied pigs. Pigs are susceptible to infection by Leptospira interrogans, just like dogs and people, and if infected a pet pig would be equally capable of shedding the bacterium in its urine and potentially transmitting the disease. The issues around requiring vaccination of pigs for leptospirosis are very similar to those around making leptospirosis a "core" vaccine in dogs. More information about this is available in the Worms & Germs post entitled "Should all dogs in Ontario be vaccinated for leptospirosis?" A pet pig would likely be exposed to the same serovars of Leptospira as a dog kept in the same area, typically by coming in contact with urine from infected wild animals such as raccoons and skunks when they go outside. However, the risk of exposure for a pig that rarely or never leaves the house would be extremely low compared to a pig that has outdoor access. Another important consideration is whether or not the pig vaccine is against the same serovars that a pet pig, instead of a commercial pig, might encounter. This will also vary depending on in what area the pig lives. The Leptospira servoars pomona and bratislava are actually host-adapted to pigs.
It is also important to vaccinate an animal with vaccines that are labeled for use in its own species. Vaccinating a pig with a vaccine meant for dogs could have unpredictable results - it may increase the risk of an adverse reaction, or it may not adequately stimulate an immune response, thereby leaving the pig essentially unvaccinated. Your veterinarian can discuss the pros and cons of vaccination in your pet with the available vaccine products.
More information about leptospirosis is also available on the Worms & Germs Resources page.
It's that time of year again - we're coming up on flu season, and the ads on the radio and the television are out, encouraging everyone to get their "flu shot," (aka influenza vaccination). Influenza isn't just a problem in people - it is a very versatile group of viruses that can infect many different species of animals.
Equine and swine influenza viruses cause serious problems in horses and pigs, respectively. Last year there was a massive outbreak of equine influenza in Australia. Because Australia was previous free of equine influenza, most of the horses there had never been vaccinated against the virus. Therefore the entire population was very susceptible to the disease and it spread very quickly. The outbreak has since been brought under control. A previous Worms & Germs post talked about an outbreak of canine influenza in dogs in Chicago IL this past summer.
Equine and canine influenza (and usually swine influenza) cannot be transmitted to people. However, there are some strains of influenza that can cross species. The most well-recognized one is certainly avian influenza (bird flu), which caused outbreaks in a number of Asian countries in 2004. Although people are much less susceptible to avian influenza than birds, the H5N1strain has caused significant illness and fatalities in people.
A lesser known fact about influenza is that pet ferrets are very susceptible to the virus, including human strains. This is part of the reason ferrets are often used as animal models of the disease in research studies. Signs of the flu in ferrets are similar to what you'd expect to see in people - fever, sneezing, runny nose and lethargy. A pet ferret can both transmit to and catch the flu from a person. Unfortunately for the ferrets, there is no available vaccine for the flu in these animals.
Lucky for us, people can be vaccinated against influenza. Most people are still far more likely to get the flu from another person than from any kind of animal. Getting your flu shot is the best way to help prevent yourself from getting the flu, and spreading it to others. However, it's important to remember that no vaccine is 100% protective, so it's still important to take a few common-sense precautions, like washing your hands frequently, and sneezing/coughing into the crook of your arm, not into your hands. (And watch out for sick ferrets!)
There is lots of information about influenza and flu vaccine available on the web, including some of the links in this post, and also on the CDC Influenza (Flu) website.
In some areas, pet vaccines are readily available from multiple sources, including the internet. Some people like to purchase vaccines and administer them to their pets themselves in order to save money. But are the cost savings really worth the risk? Here are some things to consider:
- Your veterinarian gets vaccines through a reputable distribution system, which ensures quality control, tracking of products and proper shipping and storage conditions. When buying elsewhere (especially the internet), you don't have the same level of assurance. Vaccines that have been improperly handled or stored may not be effective.
- Vaccines and drugs from some sources are of questionable quality, and you can't always be sure that you're actually getting what you wanted. Ineffective vaccines or contaminated products are a big concern. It's not saving you money if the vaccine doesn't work!
- While uncommon, vaccine reactions do occur. If your pet has an anaphylactic (severe allergic) reaction at a veterinary clinic, the chances that your pet will survive are much greater because the needed expertise, drugs and equipment are readily available. You don't have these things at your house.
- If your pet develops a problem associated with a vaccine administered by your veterinarian, the vaccine manufacturer may get involved and assist with the problem. This will NOT happen if you buy the vaccine from another source and give it yourself.
- Rabies vaccines MUST be given by a veterinarian. (In some areas it's illegal for a non-veterinarian to even possess rabies vaccine.) A pet that has received a rabies vaccine by a non-veterinarian is considered unvaccinated by public health authorities. If an unvaccinated animal is exposed to rabies, the repercussions may be much more severe, and may even include euthanasia.
- Vaccination is just one part of your pet's "wellness program." Some of the pressure for people to vaccinate their own pets is a failure of the veterinary profession to adequately emphasize the importance of preventive medicine, of which vaccines are just one component. Simply charging an owner for "annual vaccines" leads people to want to vaccinate their pets themselves because they can get the vaccines for much less money. Veterinarians need to emphasize that what they are charging for (and what is the most important component of the preventative medicine program) is an annual physical examination and health consultation, and that only a small portion of the fee is for the vaccines.
Vaccination is a minor component of your pet's preventive medicine program. A careful physical examination and consultation about potential, developing and ongoing health issues are the most important parts of this program. Even if you vaccinate your pet yourself (which is still not recommended for the reasons above), it is still critical that your pet has an annual examination. It's better for your pet's health, and it can be easier and cheaper in the long run because problems can be detected and treated early.
Echinococcus granulosus is a tapeworm of dogs that causes a condition known as hydatid disease or hydatidosis in humans. The parasite is found in many parts of the world, and is very common in some regions of southern South America, the Mediterranean, the Middle East, southwestern Asia, northern Africa and Australia. To the best of our knowledge, E. granulosus does not occur in southern Ontario, but it is present in other parts of Canada including the western provinces and northern Ontario. A related, but much nastier, tapeworm called Echinococcus multilocularis is much less commonly found in North America.
A previous Worms & Germs post described what is known as the sylvatic cycle of Echinococcus granulosus, which is thought to be a common route of infection for dogs in Canada. In the sylvatic cycle, dogs become infected with Echinococcus by eating the internal organs (usually lungs and liver) of wild game such as moose and caribou. The dogs then pass tapeworm eggs in their stool, which can cause infection in other wild animals (thus continuing the cycle) or in people who accidentally swallow the eggs. In humans, Echinococcus forms slow-growing cysts (called hydatid cysts) in different organs of the body which can be very difficult to remove or treat in some cases.
Echinococcus also has a pastoral or domestic cycle. In this cycle, dogs acquire the parasite by eating the internal organs of infected sheep, and sometimes other livestock such as cattle and swine. This cycle is potentially very important in areas where there is a lot of sheep farming. In some areas of Latin America, 20-95% of sheep at slaughter may have evidence of hydatid cysts in their organs.
It is much more difficult to tell when a dog is infected with Echinococcus compared to other tapeworms such as Taenia or Dipylidium. An adult Echinococcus is tiny - only a few milimetres long (see picture right), very unlike the long, stringy white tapeworms that most people picture. Dogs can carry hundreds, even thousands of these tiny tapeworms without showing any signs of illness at all. The eggs can sometimes be difficult to detect on fecal examinations, and when they are seen they cannot be differentiated from Taenia eggs. Nonetheless, this is still the best way to detect infection, so fecal examinations should be performed regularly.
- In areas where Echinococcus is known to exist, it's important to have your veterinarian perform fecal examinations on your dog's stool more frequently than the usual once-a-year, because of the serious zoonotic potential of this parasite.
- Always wash your hands well after handling dog stools.
- Do not let your dog eat uncooked meat, or the organs from farm animals or wild game.
For more information on Echinococcus, see Worms & Germs post entitled Echinococcus and hydatid disease - not your average tapeworm. There is also information available on the Michigan State Department of Natural Resources site.
Lower photo credit: Ontario Veterinary College
This Sunday, September 28th, is World Rabies Day. The goal of this day its to raise awareness about rabies, a disease that still kills thousands of people and animals in many parts of the world every year. While human rabies is thankfully rare in most developed countries, it is a major health concern in many other regions. Even in countries such as Canada and the US, where human cases are uncommon, diligent vigilance is required, because rabies continues to be present in wildlife, and therefore people and pets can still be exposed to this deadly disease.
A key part of rabies prevention, which is also a major focus of rabies education programs, is the need for vaccination of pets, even strictly indoor pets. Rabies vaccination is a cheap and effective way of protecting your pet, yourself and your family from this disease. It's also required by law in many areas. The implications of rabies exposure of pets that are not properly vaccinated can be severe, possibly including euthanasia or very long quarantine, even if they are not infected.
Many groups are holding events to increase awareness about rabies, such as the People and Pets Walk to End Rabies which is being held by the University of Guelph. Information from an advertisement for this event states "Although rabies does not seem like an issue at home, it is a major health problem for both humans and animals in developing countries, claiming the life of one person every ten minutes. If we work together, we can make a difference. Please show your support and join us at the walk to help make rabies history!" That statement should make it clear why we talk about rabies so much. One human death every 10 minutes is a startling figure for a disease which we should be able to control.
More information about rabies is available on the Worms & Germs Resources page.
This post has been updated with new information as of October 2, 2008.
Raccoons, just like dogs and cats, can have roundworms in their intestine. Dogs are typically infected by the species Toxocara canis, and cats are infected by Toxocara cati. Raccoons are infected by a type of roundworm from a different genus, called Baylisascaris procyonis. There is one thing that all three of the parasites have in common – the larvae of these worms can infect humans, causing a condition called visceral larval migrans.
Dogs and cats are usually dewormed as puppies and kittens, and often as adults as well, which dramatically decreases the number of pets that are infected with roundworms. Raccoons are not so lucky – in the northern and northeastern parts of North America, over 70% of raccoons may be infected with Baylisascaris. In Ontario, it has been estimated that only about 20-30% of raccoons are infected, but usually with high numbers of worms. In either case, younger raccoons are even more likely to be infected. Infected animals may shed millions of parasite eggs in their stool, and the eggs can survive in the soil for months or even years.
After a few weeks, the eggs in the raccoon stool become infective. If a person swallows the eggs, they hatch in the small intestine and release larvae. These larvae can then burrow through the wall of the intestine and migrate through tissues all over the body, causing tissue damage and inflammation. The signs of illness are often not very specific, and may include things like fever, fatigue and nausea. If the larvae migrate through the brain or spinal cord, a person may develop neurological signs like loss of coordination and muscle control. This is called neural larval migrans, which is the most serious type of disease caused by these larvae. If the larvae migrate through the eye, they can cause blindness. This condition is known as ocular larval migrans.
There have been less than 25 cases of confirmed visceral larval migrans due to Baylisascaris in the USA as of 2003, but the condition is very hard to diagnose with certainty, and it is possible that many cases are mistaken for other illnesses. The disease is also very difficult to treat, and neurological damage from neural larval migrans is usually permanent, so the best thing to do is prevent infection in the first place. Here are some tips on avoiding Baylisascaris:
- Avoid contact with raccoons. Many people think raccoons are cute, but they are wild animals. Raccoons are also a risk for transmission of rabies if a person is scratched or bitten. NEVER keep a raccoon as a pet.
- Discourage raccoons from hanging around your house. Clear brush and seal access to basements and attics where raccoons may try to nest or form latrines. Keep garbage in tightly-closed garbage cans. Eliminate outdoor water sources.
- Always wash your hands well with soap and water after working with soil (e.g. in the garden).
- Clean up raccoon latrines. This must be done very carefully - avoid getting any raccoon stool on your hands or clothes. The stool should be burned, buried or sent to a landfill. Clean the area where the stool was found with boiling water. Wash your hands very carefully when you’re done. Follow this link for more detailed information on how to identify and clean up raccoon latrines.
Baylisascaris procyonis less commonly infects animal species other than raccoons, including skunks, and it has even been found in dogs. It's important to have your dog's stool examined for parasite eggs on a regular basis (typically once or twice a year) and to follow your veterinarian's recommendations for deworming your dog.
A previous Worms & Germs post talked about the (very low) zoonotic risk of the tapeworm most commonly found in dogs and cats, Dipylidium caninum. Dogs can also carry other species of tapeworm, such as Taenia pisiformis, which cannot be naturally transmitted to people. But dogs can also carry tapeworms from the genus Echinococcus, the most common of which is E. granulosus. Echinococcus multilocularis is much less common in North America, and can also be carried by cats.
In Canada, dogs tend to be exposed to E. granulosus when they eat certain animals, particularly wild herbivores like moose and caribou. In other parts of the world, eating sheep organs is the most common way dogs are exposed. The immature form of the worm is found in the animal’s lungs, liver and other tissues. After being eaten by the dog, the worm matures in the intestine, and tapeworm eggs can soon be found in the dog’s stool. Tapeworm segments, as seen with Dipylidium infection, are usually not seen in the stool with Echinococcus. Under a microscope, it is possible to tell Dipylidium eggs from Echinococcus eggs, but it is not possible to tell Echinococcus eggs from Taenia eggs.
If a moose, caribou, sheep or another suitable “intermediate host” swallows the eggs from the dog stool, the parasite migrates through the animal’s body and forms cysts in various tissues which contain the immature form of the worm. If the animal dies or is killed, and a dog (or a wolf or coyote or related species) eats the cysts, the cycle begins again.
Unfortunately, humans can also be an “intermediate host” for these tapeworms. If a person ingests Echinococcus eggs from dog stool, the parasite can form cysts (called hydatid cysts) in many tissues and organs, including the liver, lungs, brain and heart. If the cysts are small and there are only a few, they may not cause any problems for years, and the person may never know they’re there. But as the cysts grow, they can get very large and start to interfere with the function of organs, or their size alone may be a problem, depending on where they are located. Treatment can be difficult – drugs are frequently not effective, and large problematic cysts may need to be surgically removed, if the surgery can be done safely. If a cyst bursts it can cause anaphylactic shock, which is very dangerous.
In Canada, Echinococcus infection and hydatid disease are most common in the western provinces. Nonetheless, everyone can take a few simple steps to help prevent exposure of people to Echinococcus:
- Always wash your hands after handling dog stool, even if you use a plastic bag or a scoop to pick it up.
- Your dog should have a fecal examination for intestinal parasites at least once per year, or more frequently if your dog is at increased risk of exposure to Echinococcus. If tapeworm eggs are identified, your veterinarian can prescribe medication to treat the infection.
- Monthly heartworm preventatives that are effective against other intestinal worms are not effective against tapeworms!
- Do not let your dog eat uncooked meat, especially the organs of sheep or wild game such as moose and caribou.
More information on Echinococcus and hydatid disease is available on the CDC’s Echinococcosis webpage.
A horse in Ontario was recently diagnosed with Eastern Equine Encephalitis (EEE), a serious neurological disease caused by a virus of the same name, which is transmitted by mosquitoes. The horse was from the North Durham region. The last reported cases of EEE in Ontario were in 2004. A few weeks ago, the Worms & Germs Blog talked about a large number of cases of EEE that have been reported in Florida this year.
Here are some of the key points to remember about EEE:
- Like West Nile, EEE is a seasonal disease. It is more common in warmer areas, especially some regions of the southeastern US. It is rare in cooler climates, but occasionally EEE is found in horses in Ontario.
- EEE is usually fatal in horses, and there is no effective treatment.
- EEE can also occur in people, and can be fatal in some cases.
- Infected horses cannot transmit the EEE virus to people, but if a horse gets EEE from the mosquitoes in the area, then people could also potentially be exposed to the virus by mosquitoes.
- A vaccine for EEE is available for horses, but most horses in Ontario are not vaccinated for EEE because it is so rare. Nonetheless, vaccination can be considered because the disease is so devastating when it occurs.
- As for West Nile virus, avoiding mosquitoes - for both horses and people - is an important preventative measure for EEE.
For more information, see the Worms & Germs Blog post "Eastern Equine Encephalitis – Not Just For Horses", or the CDC's website on arboviral encephalitides.
Rabies is an important disease that is almost always fatal. An important part of rabies control programs is mandatory vaccination of pets such as dogs, cats and ferrets. In general, rabies vaccination is very safe and effective. Complications from rabies vaccination are rare, but in recent years concerns have been raised about vaccine-associated sarcoma, a type of tumour that can develop at the site of vaccination. Since this complication was recognized, the vaccines themselves and the way they are administered have been changed in order to decreased the likelihood of this problem occuring, but the risk cannot be eliminated completely. For this reason, some people have tried to avoid having their pets vaccinated for rabies.
A blood test can be performed to determine antibody levels (also called a titre) against rabies virus. However, there is not enough information available to determine what antibody titre is high enough to say that an animal does not need to be re-vaccinated. Skipping rabies vaccination based on blood test results is dangerous and not recommended. While rabies is uncommon in most areas, exposure can occur, even in strictly indoor animals (e.g. if a bat gets into the house). Rabies vaccination is a legal requirement in most areas of Ontario. The implications of rabies exposure in an animal that is not "up-to-date" on its vaccines can be severe, including prolonged quarantine or euthanasia. I do not know of any jurisdictions that allow rabies antibody levels to be used in place of vaccination, and animals that are not recently vaccinated are treated as non-vaccinated, regardless of their antibody titre. The risk to your family or your pet from rabies is greater than the very tiny risk of vaccine-associated sarcoma. If you care about your pet and your family, make sure your pet is properly vaccinated against rabies.
More information about rabies can be found on the Worms & Germs Resources page.
In Ontario, and many other regions, mid-August is the beginning of the high risk period for West Nile virus infection in people and animals such as horses. The Ontario Veterinary College has published an informational video on YouTube. This video has information about measures you can take to reduce the risk of West Nile virus exposure and disease, for both people and horses. Click on the image to watch the video. More information about West Nile virus is also available in the blog post entitled West Nile virus in dogs and cats.
There is no doubt that the beneficial effects of vaccination greatly outweigh the risks, but even so adverse effects cannot be ignored. Information about duration of immunity after vaccination, vaccine safety and disease rates need to be considered when determining how often to vaccinate an animal. Unfortunately, minimal information is available about how long most vaccines are protective in dogs and cats. So there is a logical tendency to err on the side of caution and vaccinate more frequently, rather than less.
New guidelines for vaccination of cats are now available from the American Association of Feline Practitioners. The guidelines recommend longer intervals between vaccines in most older cats that have been previously (and adequately) vaccinated.
Rabies vaccination also has important legal aspects to consider. Different jurisdictions have different requirements. While a three-year rabies vaccine is available, many regions still require more frequent vaccination. Even if an animal is properly vaccinated with a three-year vaccine, if local rules require yearly vaccination, an animal vaccinated more than one year earlier could be considered unvaccinated. This can have a tremendous impact if the animal is exposed to rabies - it could mean the difference between monitoring the pet at home, or a long quarantine, or even euthanasia. Therefore, it is important to consider the duration of immunity induced by the rabies vaccine used AND the local regulations. Rabies vaccination is even important for indoor cats.
The bottom line is:
- Vaccination is an important part of your pet's preventive medicine program.
- Different cats need different vaccination programs, depending on their age and what diseases they may be exposed to.
- Potential vaccine reactions should be reported to your veterinarian, who should then report them to the appropriate regulatory authorities, so that a better understanding of adverse reaction rates can be obtained.
- Don't let vague fears of adverse reactions deter you from vaccinating your pet. If you have concerns, get informed, talk to your veterinarian, and get accurate information.
The last decade has witnessed a surge in leptospirosis in dogs throughout much of North America. Ontario and Québec have been part of the surge, which is associated with two serovars of Leptospira, grippotyphosa and pomona.
The reasons for the dramatic increase relate to: 1. The apparent spread of infection in raccoons and to a lesser extent skunks; 2. A changing climate that favours prolonged survival of these bacteria outdoors in the milder fall temperatures; 3. Perhaps to a minor extent increased awareness of the disease by veterinarians. Gillian Alton, a Masters student at the University of Guelph, has shown that the increased infection rate observed in recent years appears to have leveled off, which may be the result of widespread vaccination.
Leptospirosis should be suspected whenever there is kidney or liver inflammation of unknown origin, particularly in the fall of the year. In 2007, there were about 80 positive and 170 suspicious cases in Ontario based on blood tests submitted to the Animal Health Laboratory (AHL), University of Guelph. Since not all such blood tests go through the AHL, it is likely that there would have been about 160 positive and 350 suspicious cases based on this testing throughout Ontario, and an unknown number of cases diagnosed by PCR (a DNA-based test). If one includes cases diagnosed based on clinical signs but without laboratory testing, and about half the suspicious cases as positive cases, then there may be about 400 clinical cases (i.e. cases where the animal actually gets sick) of leptospirosis in dogs occurring annually in Ontario. Clinical leptospirosis in dogs is a serious disease and this number, if the assumptions are correct, represents a high burden of infection.
Arguments for recommending the new 4-way leptospiral vaccines as a “core” vaccine (i.e. all dogs should be vaccinated) in Ontario are:
- The suggested size of the problem;
- The often serious nature of the disease;
- The zoonotic potential of the infection (a small number of human infections acquired from dogs have been recognized in Ontario and Québec in recent years);
- The ongoing widespread presence and sometimes large numbers of raccoons in suburban and urban Ontario;
- The diagnosis of canine leptospirosis throughout the province;
- The diagnosis of the disease in dogs of all types, not just the “male hunting dog” which is sometimes conventionally regarded as “high risk”.
- The sporadic nature of the infection, including the lack of exposure of some dogs to raccoons and other wildlife sources;
- The number of vaccine reactions associated with leptospiral vaccines (this is not a significant problem with at least one of the vaccines);
- The considerable confusion caused by the (almost certainly totally unfounded) suspicion that serovar autumnalis causes canine leptospirosis, but is not in the new vaccines;
- The lack of inclusion of serovar bratislava in the vaccine (although this serovar seems to cause only mild disease in dogs);
- The annual cost of revaccination.
This incident highlights a few things, including the fact that rabies, even in dogs, can be quite common in some areas of the world, and that movement of animals across borders may increase the risk of introducing infectious diseases. Certainly, cases such as this should not be used to say that these dogs should not be adopted. Rabies (or other serious disease) is a rare event in these situations, and the overall risks to people are minimal if proper procedures are followed. This includes making sure that all animals remain accounted for after arrival, and pursing proper diagnostic testing in the event that they show signs of illness (as was done here). The other dogs that came back with the rabid dog are being monitored. The risk of transmission from this dog to the others is quite low, since it is unlikely that the dog was able to transmit rabies 3 weeks ago, well in advance of developing signs of disease. In some cases it can be weeks to months from the time a dog (or other animal) is exposed to rabies until they become infectious to others. Presumably, people that had contact with this dog recently are now undergoing post-exposure treatment.
More information about rabies can be found on the Worms & Germs Resources page.
People typically realize their pet has tapeworms when they see small tapeworm segments in the animal's stool. These whitish, rice-sized pieces (called proglottids, see the picture on the right) are parts of the adult tapeworm, which break off and are passed in the stool.
Tapeworms are not usually harmful to dogs and cats, particularly if only one or a few worms are present. In some situations, weight loss can occur. Affected animals may 'scoot' (drag their rear end across the ground) because of irritation from tapeworm segments that are passed in the stool.
Diagnosis of a tapeworm infestation is easiest through identification of tapeworm segments in stool. Identification of tapeworm eggs in stool samples through routine testing used for other intestinal parasites is less useful, as the bare eggs are infrequently shed in stool. Therefore, a negative fecal egg examination does not rule out tapeworms.
Dipylidium infections are extremely rare in people. Children are at greatest risk. Disease in people, if present, is usually mild and easily treated. However, finding tapeworms in a person's stool can be distressing to the individual (and their family). Dipylidium cannot be transmitted directly from animals to people. People and pets get infected by ingesting a flea that is infected with tapeworm larvae. Therefore, flea control is the most important aspect of tapeworm prevention. People that find tapeworm segments in their stool should contact their physician to determine whether they are actually tapeworms (people often mistake other things for tapeworm segments) and to determine whether any treatment is needed.
There are specific dewormers that can be prescribed by your veterinarian to eliminate tapeworms in pets. It is also important to take measures to control fleas and prevent dogs and cats from catching and eating animals that might be carrying fleas.
If you care about your family and your pets, vaccinate you pets against rabies.
More information about rabies is available in our Resources page.
Various bacteria that can cause diarrhea in people can be carried by kittens, including Salmonella and Campylobacter. These are shed in the stool of infected animals, and people can become ill from handling the animal or stool-contaminated areas. Kittens may have higher rates of carriage of these bacteria than adult cats. Another bacterium that can be carried commonly by kittens is Bartonella henselae, the cause of cat scratch disease. This is transmitted by bites, scratches and fleas, and is just one reason for proper flea control.
Stray kittens are also more likely to carry Toxoplasma, a parasite that is a concern in pregnant women and immunocompromised individuals. Other intestinal parasites such a roundworms are also a concern. Kittens are more likely to have these parasites than adult cats. Stool contamination of the haircoat is presumably more common in kittens as well because they are not as good about cleaning themselves as adult cats. So just handling a kitten, even if you avoid its stool, may result in exposure to some of these parasites and bacteria.
Rabies is always a concern, and widespread exposure of people to rabies has occurred from infected litters of kittens. While uncommon, rabies is a major concern because it is almost invariably fatal. Any stray (or recently rescued) animal that starts acting strangely should be considered a rabies-suspect and be taken to a vet immediately. [More information on rabies, and other topics, is available in our Resources page].
Stray kittens can also carry various infectious diseases that can be transmitted to other cats in the household, such as feline leukemia virus, panleukopenia, rhinotracheitis and calicivirus.
Overall, the risks from adopting stray kittens are low, but they are real. If you are going to adopt/rescue a stray kitten, keep these things in mind:
- Take the kitten to your vet as soon as possible to identify any health issues and determine the required vaccination, deworming and flea control program
- Wash your hands after handling the new kitten
- Keep the new kitten in a confined area while litterbox training is underway to reduce accidents throughout the house
- If you have another cat, make sure it is up-to-date on vaccinations before the kitten comes into the house.
- If the kitten gets sick, make sure it is taken to a vet. If it dies suddenly, make sure you take it to your vet to determine whether testing for rabies is required.
- Pregnant women and households with immunocompromised individuals should not adopt stray kittens.
Wildlife should be left in the wild. While some wild animals, especially babies, are hard to resist, little good usually comes from intervention of the general public. This is particularly true when well meaning people ‘rescue’ baby wildlife. Often, ‘orphaned’ wildlife are not orphans; the parents are hiding nearby and would have returned. Few animal facilities are properly equipped or licensed to properly deal with wildlife, and these ‘rescued’ orphans often end up being euthanized. Some people try to nurse these animals themselves but few can do it properly. It’s also illegal in many areas. Add that to the obvious risk of rabies, as highlighted here, and it should be clear that wildlife should be left alone. It’s also a good reminder of the need to vaccinate your pets because rabies exposure can occur in many different ways. The pets in this situation are reportedly under 45 day quarantine, which is certainly not something you want to do, but is much better than what would happen in many jurisdictions in the case of rabies exposure of an unvaccinated pet (long strict quarantine or euthanasia).
Baby raccoons are very cute and hard to resist, but like many other forms of temptation, danger, in this case in the form of infectious diseases, can lurk just around the corner. More information on rabies is available in our Resources section.
But there are also dangers lurking in the forests – microscopic dangers carried by tiny insects and other bugs. Ticks in particular are problematic. Certain ticks can carry a number of diseases that can make dogs sick, including Lyme disease (caused by Borrelia burgdorferi) and Rocky Mountain Spotted Fever (RMSF)(caused by Rickettsia rickettsii ). Both Lyme disease and RMSF are more common in certain areas where the tick species that carry them are present. You can NOT catch these diseases from your dog, but both you and your dog can be infected by the ticks that carry them. People can also be exposed to these pathogens by accidentally crushing an infected tick while trying to remove it from their dog. Ticks must be removed very carefully to ensure that the entire tick is removed, including the head and mouth pieces, without crushing it. If you're not sure how, contact your veterinarian. Also, the sooner the tick is removed, the less likely it is to transmit certain diseases, so be sure to check your dog thoroughly for ticks when you come back from a walk in the bush.
The Minnesota Department of Health recently reported that the number of cases of (human) Lyme disease increased in that state in 2007. This could be because of spreading tick populations, more people participating in activities in tick-inhabited areas, or increasing awareness and diagnosis of the disease by physicians.
If you and your canine companion will be spending time in some of the wilder and woodier parts of the great outdoors, talk to your veterinarian about what you can do to protect your dog. There are vaccines available for Lyme disease and the bacterial infection leptospirosis (which is also transmissible to people). Flea and tick preventatives are also very important, and many of today’s products are very effective. People should always wear insect repellent when camping or hiking in the woods. Visit the Health Canada website for safety tips on using personal insect repellents. All dogs should be vaccinated for rabies, whether they go camping in the backwoods or they’re house-bound city-slickers.
- Never handle a bat
- Assume all bats are rabid until proven otherwise
- Any contact with a bat is considered to be rabies exposure unless the bat has been tested and shown to be negative. All bat exposures should be reported to the appropriate public health authorities.
- Despite all the old stories, rabies exposure treatment is not horrible…it’s just a series of shots in the arm.
- Vaccinate your pets. You never know when they’ll encounter a bat…inside or out.
More information on rabies is available in our Resources area.
Unfortunately, rabies is common in China, with the number of cases increasing dramatically over the last decade. In 1996, there were 163 humans deaths due to rabies. This number increased to 3380 in 2007. Because of the seriousness of disease, the number of deaths and the low vaccination rate in dogs, a mandatory vaccination policy for dogs has been put in place. Free rabies vaccination is provided annually for each licensed dog. This could have a tremendous impact on the number of rabies cases, at least in certain regions. Control of rabies in rural areas is more problematic because of the lack of an organized registration and vaccination system for dogs in those areas. Perhaps not surprisingly, most cases of rabies occur in these rural regions.
So, the 2008 Beijing Olympics may have benefits for the dogs of China as well, or at least those in Beijing. This is certainly a preferred approach to the reports from last year of mass killing of thousands of dogs (including pets). Let's hope this progressive approach continues and the impact of this horrible disease decreases.
On a related note, the latest human death from rabies in Beijing was a person who was bitten by a stray dog two months before he became ill. He didn't seek medical attention at the time of the bite, he just cleaned the wound himself. If he had been treated for possible rabies exposure, he'd be alive today. While rabies is uncommon in many areas, no bite from an animal should be taken lightly. Rabies should always be considered and appropriate measures taken. More information about rabies is available in our Resources section.
Why should I vaccinate Fluffy, he's an indoor cat? (aka Why I'm glad I vaccinated Finnegan, my indoor cat)
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, even with indoor-only animals….if you care about yourself, your family and your pets, vaccinate your pets against rabies. In most places it’s the law. It’s also good sense.
2012 International Clostridium difficile Symposium
2012 International Conference on Equine Infectious Diseases IX
2011 ASM-ESCMID Conference on Methicillin-resistant staphylococci in animals
- Miconazole susceptibility of MRSA and MRSP
- Livestock associated MRSA in community hospitals in Ontario
- Equine hospital MRSA surveillance
- Biofilm production by S. pseudintermedius
- Methicillin-resistant staphylococcal pyoderma in dogs, and impact of treatment on colonization rates
- Surgical site infections in a small animal hospital
2011 University of Guelph Centre for Public Health and Zoonoses Symposium
- Pet ownership, interactions and animal-associated disease risks in Canadian households
- Metagenomic investigation of the oral microflora in healthy dogs
2011 Canadian Animal Health Laboratorians Conference
2011 Canadian Association of Clinical Microbiology and Infectious Diseases
- 2011 American College of Veterinary Internal Medicine Forum, June
- 2011 ASM-ESCMID conference on methicillin-resistant staphylococci in animals, Sept