Worms & Germs Blog

Echinococcus multilocularis: Ontario, Canada

Posted in Deworming, Dogs, Parasites

Echinococcus multilocularis, a small tapeworm with a big name, is causing big concerns in Ontario, an area that was until recently considered free of this parasite. This tapeworm is normally found in the intestinal tract of wild canids (e.g. coyotes, foxes) and can also infect dogs. That itself isn’t a problem, since the intestinal form of the worm doesn’t make these animals sick. The concern arises when something (or someone) ingests tapeworm eggs from the feces of an animal with the intestinal infection, potentially leading to a different form of infection called alveolar echinococcosis (AE).  In this form, the parasite causes tumour-like cysts to form in various parts of the body, particularly in the liver, and the condition can be very difficult to treat by the time it is diagnosed.

In the normal life cycle of this tapeworm, wild canids shed eggs in their feces and those eggs are eaten by small rodents, who develop the parasitic cysts in their bodies. When a canid eats one of those infected rodents, the life cycle continues, as the parasite grows into its adult stage in the canid’s gut and produces more eggs.

That’s bad for rodents, but the problem is that this “intermediate host” stage can occur in more than rodents – it can also occur in dogs and people (and occasionally other species).

Alveolar echinococcosis has been diagnosed in a small number of Ontario dogs (with no travel history) since 2012, raising questions about how they got infected. The concern was that this parasite might have become established in our wild canid population, which would result in ongoing and widespread risk to people and other animals, and would be hard to control.

Those concerns have been proven true, by a study just published in Emerging Infectious Diseases (Kotwa et al. 2019). For this study, fecal samples were collected from 460 wild canids in Ontario. An astounding 23% of them were positive for Echinococcus multilocularis, with infection concentrated most heavily in the western-central part of the province.

This remarkable set of results shows that this parasite is by now well established, at least in parts of Ontario, and that there is local exposure risk through direct or indirect contact with wild canid feces. Dogs that are prone to eating feces (I own one of those) or rodents (dead or alive) are at highest risk of exposure. Humans who have contact with coyote feces (e.g. hunters, trappers) are probably also at particularly high risk, but since canids live in such close proximity to people in some areas, including large urban centres, there’s a chance for exposure of lots of people through contact with fecally-contaminated outdoor sites.

What is the status of this disease in people in Ontario?

  • We don’t know. The incubation period (the time from ingesting eggs to the time you get sick) is very long (typically 5-15 years). That means we may not really know what’s going on in people for some time. Since we have this parasite in wild canids and it’s spilled over into dogs, it’s almost certain that there are infected people in the province, they just don’t know it yet. That’s not meant to be alarmist, since it’s still going to be a rare disease; however, we won’t know the scope of the problem for some time.  Echinococcus multilocularis has also recently been made provincially reportable in Ontario, to help us gather more data.

What can we do?

  • Avoid contact with wild canids and wild canid feces as much as possible.
  • Do our best to prevent and treat intestinal infection in dogs.  In other areas of the world where this parasite is widespread, dog ownership has been identified as a risk factor for human infection, probably because dogs act as a bridge between households and the wildlife cycle of this parasite.  We can treat dogs for tapeworms, but this isn’t usually part of routine deworming protocols, so currently only a small percentage of dogs are treated.  I’ve been treating my dog with praziquantel monthly for the past couple of years, since emergence of the parasite was identified.  I recommend it now, especially for dogs that might have contact with wild canids or that are prone to eating things like feces and small rodents.

More information about this parasite can be found on the Worms & Germs Resources – Pets page, and at emultiontario.com.

Image from Kotwa et al. 2019, Figure 2A: the unadjusted prevalence of Echinococcus multilocularis tapeworms in coyotes and foxes across 25 southern Ontario public health units, 2015–2017.

Wash your hands and save a skunk

Posted in Other animals

Well, not really. Presumably most people don’t have direct contact with skunks; however, that doesn’t mean skunks can’t pick up viruses from us.

A study published in Zoonoses and Public Health (Britton et al. 2018) investigated human H1N1 influenza in wild skunks in the greater Vancouver, BC (Canada) area, following up on an earlier study that found influenza virus in 2/50 skunks (both skunks had human contact). They looked at the nose, lungs and feces of 80 free-ranging skunks around Vancouver and found influenza A(H1N1)pdm09 in one skunk, which had been hit by a car. The skunk was euthanized because of the severity of its injuries and didn’t have any obvious signs of respiratory disease, but when tissues were examined histologically (under a microscope), there were signs of inflammation in the nasal passages. A flu virus was isolated and testing identified it as the human pandemic H1N1 strain.

Given the strain, it’s assumed that the skunk was infected by a person. It probably wasn’t from direct contact, but there are various ways that indirect contact could occur. One would be through garbage. It’s fairly easy to envision a skunk rooting through a garbage bag that might have contained used tissues from a person with flu. Whether a skunk can pass the virus on to other skunks (or to other species) is a question that remains unanswered

Movement of this flu strain into different animal species isn’t too surprising. It’s been found in a few species already, including household pets (dogs, cats, and ferrets). Skunks probably play little to no role in human flu transmission, and infected skunks may be “dead-end hosts” (infected individuals that don’t pass the virus on any further) or at least rarely affected enough that they don’t pose much risk for propagating infection. Regardless, this show how infectious diseases can do strange and unexpected things, and that we’re not a population of people living amongst populations of dogs, cats, cattle, birds… and skunks… but rather we’re all one big population of animals that can periodically share diseases.

So, washing your hands may not save a skunk, but it’s still good for you (and those around you, both human and animal). Flu also isn’t the reason I’d  stay away from skunks – rabies and getting sprayed are far bigger issues.  But the concepts of “let wildlife stay in the wild” and “leave them alone” should never be forgotten (though they sometime are).

Rabies knowledge of vets and physicians

Posted in Cats, Dogs, Rabies

I spend a lot of time answering questions about rabies exposures, and sometimes trying to clear up misinformation. Rabies is a very important infectious disease but in many regions (like here) it’s fortunately rare in domestic animals and people. However, rarity can breed complacency or lack of (or loss of) knowledge. That creates problems when people are thrust into the middle of a potential rabies exposure situation, in which they are frequently worried and stressed, without a lot of experience.

A recent study in Zoonoses and Public Health looked at rabies knowledge amongst 125 vets and 952 physicians in Washington, DC (Hennenfent et al. 2018).

Results were mixed, and there were (unsurprisingly) some differences between the professions.

  • Vets were more likely to correctly answer questions about animal vectors and disease in animals.
  • 88-89% of respondents said raccoons and bats are sources. That’s a high number but it’s concerning that it’s not 100% since those are very common and important rabies reservoirs. If people don’t know what species are of concern, they might not identify potential exposure scenarios.

Physicians were more likely to get transmission questions right.

  • However, they were also more likely to say you could be exposed by stepping on feral cat feces (for the record, you can’t).
  • 5% of physicians said that pigeons can transmit rabies virus. That’s a big “no” since rabies transmission only involves mammals.

Veterinarians were more likely to correctly identify rabies-free countries.

  • This is of relevance for querying and assessing risk for people (and animals) that have traveled or are planning to travel.

Knowledge of post-exposure prophylaxis regimens wasn’t great, with only 39% of physicians getting that right.

  • That’s a bit concerning, but maybe not a big deal because once the decision is made to give a patient post-exposure prophylaxis, presumably there would be a check of what to do, and public health involvement would help ensure the appropriate course (I hope). The key is determining whether a patient needs treatment and having support mechanisms in place.

Veterinarians were more likely to know the appropriate response to exposure of a person that has been previously vaccinated (i.e. you still get post-exposure prophylaxis, just a different course).

Only 50% of veterinarians identified the proper quarantine period for exposed vaccinated dogs, and even fewer (19%) got the answer right for unvaccinated dogs.

  • That’s maybe not a big deal either IF there is a good public health/animal health support structure to help let veterinarians and owners know what needs to be done, or IF veterinarians simply look up the information after encountering a case. Just because they don’t know offhand doesn’t mean they won’t act appropriately. However, better baseline knowledge is ideal.
  • As with physicians, identifying when to act is the most important, since the what component should be easy to determine.

Why is rabies knowledge sub-optimal?

  • It’s probably because of a few factors. One is there’s not much focus on the disease in veterinary or medical curricula. Those programs are already jam-packed, and everyone’s crying for more time for their subject area. The applied aspects of rabies exposure are probably variably and minimally covered (if covered at all). I focus on rabies response in an infection control lecture to 2nd year veterinary students, but that’s just part of one lecture, a couple of years before they graduate.
  • Rarity results in knowledge loss and complacency. Even if a veterinarian or physician knows about rabies when they graduate, if they don’t have to think about it for years, that knowledge is probably gone (or very fuzzy… which may be worse).

Does baseline knowledge matter?

  • Yes and no.
  • It’s most important to be able to identify an issue. As long as veterinarians and physicians have knowledge that triggers thoughts of rabies exposure, that’s the key. If you don’t think about rabies, you can’t act. If you think about it and are diligent, there are resources to help guide the response in both animals and humans. Public health can (hopefully) help with the response if there is potential human exposure (if they have the right knowledge and interest, which can also be variable).

More rabies knowledge would be great. How to get that is a challenge. We’re unlikely to get more time in student curricula. We can sneak information into continuing education seminars but it’s hard to focus on rabies because people are unlikely to attend a talk on what they perceive to be a rare topic or one that doesn’t really  apply to them (especially when there are lots of competing talks about things they have to deal with on a day-to-day basis). When I talk about rabies to veterinary or physician groups, it’s usually part of a broader zoonotic disease or one health topic.  Even then, it’s still a niche topic, and as with lots of continuing education, many people who really need the information are less likely to show up because it’s not something they care about or realize they don’t understand.

The study results are interesting, and rabies knowledge among physicians and veterinarians would ideally be better. However, we’re better off focusing on things that help these professionals think about rabies and making sure there are good support systems, rather than trying to cram more specific, automatic recall knowledge into their heads. The former is feasible and the latter is unlikely to happen.

Dogs and tularemia

Posted in Dogs

Tularemia is a nasty bacterial disease. The bug that causes it, Francisella tularensis, is a category A bioterrorism agent (along with things like anthrax, botulism, plague, smallpox and Ebola virus). It’s classified as that because it’s highly transmissible and causes serious disease, so it’s something you definitely don’t want.

The bacterium circulates in the wild, most often associated with rabbits and rodents. Human infections are usually associated with exposure to these types of wild animals (including things like – gross as it is – running over a wild rabbit with a lawnmower and aerosolizing the bacterium). However, one complicating factor with this bug is that it can be spread a lot of different ways, including via tick and fly bites, water and minor contact with infected animals (e.g. just touching their skin).

Among domestic pets, cats are most commonly implicated in human infection, because cats with outdoor access tend to hunt species that harbor tularemia (fitting with the “it’s better off for cats to be indoors if they tolerate it” statement I made in my last post… that got lots of comments both for and against), and because they are fairly susceptible to infection when they get exposed. However, a variety of animals can harbor and transmit the bacterium.

Dogs are lower risk but not no risk, as a recent paper in Zoonoses and Public Health (Kwit et al. 2018) explains. They looked at US tularemia surveillance data from 2006-2016, and focused on the 24 cases that were deemed dog-associated. Whether those were all truly from dogs can’t be guaranteed, and it’s possible that some of the other cases were dog-associated but the link wasn’t investigated or identified.

Among the highlights:

  • Most cases were from Missouri, Colorado and Kansas, consistent with what we know about tularemia in general in the US.
  • Outcome was known for 20 of the affected people. Two died.
  • 50% of cases were thought to be from direct contact with dogs, including bites or scratches, but also contacts such “face snuggling” and licking
  • 33% of people were exposed from contact with carcasses brought home by their dogs.
  • 17% of cases were associated with ticks thought to have been brought in by dogs. Implicating dogs as a “source” of ticks in a household is tough, because if a dog is exposed to ticks, people in the same area have a similar risk of being exposed if they’re outside. The bigger risk might be an increased tendency to spend time in tick-infested areas when walking said dogs.
  • Not much dog-health information was reported. Four people had contact with “ill” dogs but it’s not clear how many dogs might have had tularemia vs been infected without signs of disease vs been contaminated by the bacterium but not infected (and been “ill” from something else entirely).
  • One dog was diagnosed with tularemia. That’s not too surprising since dogs tend not to get sick or at least not get very sick from tularemia (as opposed to cats), so it’s easy to miss a potential dog case.

The take-home messages are pretty straightforward. Tularemia is very rare and very low of my list of disease concerns when it comes to dogs. However, avoiding tularemia involves common sense practices that should help reduce a lot of other risks at the same time.

  • Reduce roaming of dogs, especially dogs that are able to or like to interact (e.g. chase, hunt) wildlife like rabbits.
  • If your dog brings back a carcass, handle it with care. Try to avoid touching it and, if you have to, wear gloves, then wash your hands after removing the gloves. Avoid contact with the dog’s mouth for a while (who knows how long… maybe a couple hours?) if it had a carcass in its mouth.
  • Reduce tick exposure as much as possible (for dogs and people).
  • Use tick preventives in dogs to reduce the risk of tickborne disease exposure. A variety of ticks can transmit F. tularensis, including the dog tick (Dermacentor variabilis), the wood tick (Dermacentor andersonii) and the Lone Star tick (Amblyomma americanum).
  • Mention rabbit and rodent exposure potential to your veterinarian if your dog gets sick.
  • Mention your dog ownership, your dog’s potential contact with wildlife, and any contact you have had with wildlife (dead or alive) to your physician if you get sick.

 

Endangered panthers and a domestic cat virus

Posted in Cats, Deworming, Vaccination

The indoor vs outdoor cat debate never seems to end.

Some decry outdoor cats as the world’s most destructive “invasive species.”

  • Some say that outdoor cats do what outdoor cats (and any other carnivores) do… they hunt to eat.

Cats kill large numbers of birds every year.

  • So do lots of other things.

In an ideal world, we’d have no feral cats and all pet cats would live happily inside.

  • We don’t live in that world.

I have one indoor cat (Finnegan) and two outdoor cats. They’re outdoor cats out of necessity. The first one (Rumple) was adopted through the Guelph Humane Society’s working cat adoption program. Basically, these are cats that are deemed unadoptable as house pets or that otherwise wouldn’t do well in a household situation. Rumple’s a major suck and might tolerate an indoor/outdoor lifestyle (although Finnegan would disagree with that notion). So, despite nominally being a barn cat, he spend his summer’s on our deck and winters in his heated house in the garage. Yes, he hunts (although probably not too much since he’s well fed). He’s vaccinated, dewormed, neutered and microchipped. He has an ecological impact but it’s pretty minimal in the grand scheme.The other outdoor cat (Alice) was a wayward feral female cat that Rumple adopted. She started hanging around, Rumple took her in and she had a litter of kittens shortly thereafter. They were adopted into homes, she was spayed, vaccinated, dewormed and microchipped and she’s getting fat, living the good (outdoor life). We can pet her on her terms but there’s no way she’d tolerate an indoor lifestyle.

Yes, I realize they have an ecological impact. Yes, I realize (and have constant concern) that there are risks from cars, coyotes and other critters. However, this is the lifestyle that suits them and it’s a balance I accept.

Anyway, that’s a very long and somewhat philosophical introduction to the topic of this post: introduction of feline leukemia virus (FeLV) into endangered Florida panthers. A recent paper in Emerging Infectious Diseases (Chiu et al. 2018) describes multiple introductions of this virus into the panther population, which is a significant concern for a species with such small numbers.

Feline leukemia virus is an important cause of disease in domestic cats and periodically spills over into wild felids (members of the cat family), sometimes with high rates of illness and death. In Florida, an outbreak of FeLV was identified in panthers between 2001 and 2004. Between 2004 and 2010, FeLV was not identified in any of 125 panthers tested in the state. However, since 2010, 6 panthers that were found dead tested positive. One of those might have died because of the virus. The other 5 were killed on the road but were infected. It may seem like a small number, but it’s a relevant number in a such a small, endangered population.  It’s also it’s impossible to monitor and test all animals, so 6 infected animals in an under-estimate of the prevalence in the whole population.

Genetic testing of the virus was used to sort out why this was happening, and to determine how linked the infections were. The viruses from the 2001-2004 and 2010-2016 outbreaks were distinct, indicating separate introductions into the panther population. Presumably, panthers were infected by cats on at least two different occasions, likely when domestic cats were preyed on by panthers.

Transfer of FeLV from cats to panthers is probably a rare event, considering the number of cats that are encountered (it’s been estimated that “domestic” cats account for ~5% of the panther diet). However, as we know with many diseases and many species, all it takes is a single encounter for a new pathogen to establish itself in the population.

My take home messages from all this are:

  • It’s better for domestic cats to be indoors if they tolerate it. It reduces the risk to them and wildlife.
  • Not all cats can live solely (or partly) indoors.
  • We should optimize the health of cats that go outdoors and make sure that the best preventive medicine program is in place for them, to reduce the risk to them and the risk of them passing something on to other cats or other species.
  • Cats known to be harbouring important pathogens such as FeLV and FIV should be kept inside if at all possible.
  • Owners of cats that go outside should talk to their veterinarian about risks (to the cat and others) of being outside and determine an appropriate preventive medicine program. (They should absolutely be spayed or neutered.)
  • Particular care must be taken in areas where there are wild felids, particularly endangered species.

Annual US rabies report 2017

Posted in Cats, Dogs, Horses, Other animals, Rabies, Vaccination

As is typical for this time of year, the annual US rabies report has been published in the Journal of the American Veterinary Medical Association (Ma et al, 2018).

Here are some highlights:

  • 4454 rabid animals were identified across the country. This is certainly a marked underestimate of the actual number since most rabid animals aren’t seen or tested.
  • This number is down 9% from 2016. I’m not sure what that means (or if it means anything). Rabies numbers can be impacted by true changes in rabies cases, or they can increase or decrease based on how intensively people are looking. Changes in surveillance can result in changes in numbers, even when the disease is unchanged (this is known as surveillance bias).
  • The most commonly affected species were the usual suspects and the known rabies reservoir species:
    • Bats: 32%
    • Raccoons: 29%
    • Skunks: 21%
    • Foxes: 7%
  • There were regional differences in the predominant rabies virus strains (fox, raccoon, etc.), as shown in the figures below. Raccoon rabies diagnoses were concentrated along the eastern part of the US, consistent with the past.
  • As usual, cats led the rabid domestic animals, accounting for 6% of cases, followed by dogs (1.4%) and cattle (0.8%). The higher number of affected cats likely reflects large numbers of stray cats and cats with uncontrolled outdoor access, their tendency to tangle with rabies reservoir species and low overall vaccination rates. Cats were mainly identified in the northeast.
  • Two human cases were identified during the year. One had been bitten by a dog while travelling in India, a country where canine rabies is rampant. The other acquired rabies in the US from a bat.

Rabies remains an ever-present threat in the US, like many other countries. The bad thing about rabies is that it’s almost invariably fatal. The good thing is that it’s almost completely preventable.

Keys to rabies prevention include:

  • Avoiding contact with wildlife.
  • Vaccinating domestic animals, both for their health and because they can act as a bridge between wildlife and people.
  • Providing post-exposure prophylaxis to potentially exposed individuals.
  • Educating the public so they know more about rabies, how to avoid it and when to seek healthcare. This is a critical aspect that’s often the weak link. People get rabies because they don’t seek healthcare after an exposure.

More information about rabies can be found on the Worms & Germs Resources -Pets page.

Holiday bites

Posted in Dogs, Rabies, Vaccination

No, we haven’t changed to a cooking blog, I’m talking about bites of the canine variety. I can’t think of any specific data that would show it, but I wonder whether bites are more common around the holidays, with disrupted schedules and more visitors (and a potential midnight intruder in a red suit).

The rabies-related response to a bite is nothing new, but it still causes a lot of confusion so I’ll re-hash it here. Rules vary a bit (no pun intended) by jurisdiction so relevant personnel (e.g. public health, animal health) should be contacted,  but here’s the general response when a dog bites a person.

What’s the concern?

  • Rabies exposure from dog bites in areas where canine rabies is widespread (e.g. Africa, India, China) is a major concern. In other areas (e.g. Canada, the US), rabies is very rare in dogs. However, since rabies is almost invariably fatal in people, we don’t mess around. The immediate concern is to figure out whether the dog might have been shedding rabies virus in saliva at the time of the bite.
  • Rabies isn’t the only problem, as trauma from the bite and various other infections diseases are also of concern, but we’ll focus on rabies here.

What happens to the dog?

  • A 10 day observation period is pretty much universal. This can be a strict quarantine or less formal confinement, with the key being to keep the dog under control and make sure it’s normal 10 days after the bite.

What is the purpose of the observation/quarantine period?

  • Shedding of rabies occurs quite late in course of infection. The virus has to travel  through the body from where the dog was bitten, via nerves, to the brain, and then through nerves down to the salivary glands, at which point the dog becomes infectious to others. Therefore, by the time rabies virus can be shed in saliva, it’s already been in the brain for a little while. When it reaches the brain, signs of rabies develop pretty soon thereafter due to damage caused by the infection. So, if a dog is still neurologically normal 10 days after the bite, it would not have had rabies virus in its  saliva when the bite occurred.

What if the dog is vaccinated against rabies?

  • It doesn’t really matter. The vaccination status does not generally impact the response to a dog that bites someone (it does change the response if a dog is bitten by something else (e.g. fight with a raccoon) and is potentially exposed to rabies).
  • Rabies vaccination is very effective but given the severity of rabies, we can’t assume that it’s impossible for a vaccinated dog to have rabies.

What happens if the dog is not available for observation/quarantine?

  • If the dog can’t be identified and quarantined, you can’t rule out rabies. Therefore, it ends up being a discussion of the likelihood of rabies and whether post-exposure prophylaxis is indicated. Usually, the default is to treat it as exposure even if it’s very unlikely, since post-exposure prophylaxis is very effective and rabies is very bad.

What if the dog can’t be observed/quarantined?

  • If there’s a health or safety reason that quarantine can’t be done, euthanasia is indicated. This allows for testing of the animal’s brain, which is the only definitive way to determine if the dog had rabies at the time of the bite. Quarantine is preferred from a dog welfare standpoint, obviously, and it’s also best for the person in most situations. If the dog is alive and clinically normal in 10 days, rabies is not an issue. If the dog is euthanized, there is always the low (but possible) chance of an equivocal test, or, as I wrote about last year, a brain that gets lost in transit.

What else?

  • The big thing that often gets overlooked is consideration of why the bite happened in the first place. This is important to help prevent it from happening again.  It involves thinking about potential health or behavioural problems in the dog, poor supervision or poor handling on the part of the people involved. Bites shouldn’t be dismissed as an unavoidable consequence of dog contact.

Update: Canine influenza, Ontario (December 3)

Posted in Dogs, Other diseases

I’m once again prepared to call Ontario (and Canada) canine influenza-free… for now, at least. The latest cluster, associated with another importation of the virus from China, seems to have been contained.

The last new positive case was identified October 30, with the likely date of exposure being October 23. We are now beyond the 28-day shedding window that we use for H3N2 canine flu, plus some extra time tacked on to give us time to identify new cases that might have been exposed near the end of the last dog’s shedding period.

The apparent abrupt halt in new positive cases, within two weeks of the first case, once again shows how this highly contagious virus can be contained with quick identification (astute primary care vets), quick response (testing, contact tracing and communication) and responsible ownership (complying with requests to keep infected dogs away from other dogs).

Will canine flu come back?

  • Probably. It’s widespread in Asia and parts of the US. We import a lot of dogs from those areas.

Can we reduce the risk?

  • Yes. Quarantine and testing of new dogs after they have been imported from high risk areas is a fairly straightforward measure that is used too uncommonly.

What else about imported dogs?

  • We need to figure out more about the risks associated with importing dogs and how we can contain those risks. While I’d like to see importations decrease, I’m not naive enough to think that’s going to happen anytime soon, and at this point, I’d rather work with importers to reduce the risk. More on that soon.

Feline TB warning: Possible food link

Posted in Cats

A recent article from the Veterinary Information Network (VIN) News Service describes a strange cluster of feline tuberculosis (TB) cases in the UK, with a possible link to food. In cats, TB is rare and usually caused by Mycobacterium bovis, a bacterium most often associated with cattle and bovine TB. M. bovis is present in the UK and circulates in some wildlife species. TB can be a nasty disease, and without treatment, it’s fatal (in humans and animals). While potentially treatable, the prognosis is still guarded and months of antibiotics are required. There is also some (but poorly understood) risk to owners of infected animals, since M. bovis can infect people too. Cat-human infections are rare (or rarely identified) but it’s still a concern.

The cluster of cases in the UK is unusual for a few reasons:

  • One is that it occurred at all, since TB is cats is rare.
  • Another is that it affected young cats with no history of outdoor access. Typically, cats get infected outside from bites and scratches that occur when hunting.
  • All cats were fed the same brand of a commercial frozen raw diet.
  • Some of the cases were in cats living in low risk areas of the UK.

In cats, M. bovis usually causes skin and soft tissue infections, a testament to the typical route of exposure in this species (i.e. bites). However, the cases in this report had intestinal disease, characterized by signs such as weight loss, abdominal masses and diarrhea, consistent with exposure through ingestion of contaminated food.

Dr. Danielle Gunn-Moore of the University of Edinburgh is leading the investigation and emphasizes a few points:

  • Veterinarians in the UK should be aware of TB in cats, as infected animals may show non-specific signs of infection.
  • If TB is a possible reason for a cat’s illness, diagnostic testing should be performed ASAP.
  • Food history should be questioned in potential cases, with particular attention to raw diets.
  • Veterinarians in the UK that suspect they have a case of feline TB should contact Dr. Gunn-Moore.

Update: Canine influenza, Ontario (November 17)

Posted in Dogs

I’ve been behind on posts so here’s a quick update: things seem to be going well in the latest Canadian H3N2 canine influenza outbreak. Here’s the rundown:

  • After eradicating the last outbreak in the spring, cases were identified again in mid-October, associated with more importation of dogs from Asia.
  • The last new positive dog was identified October 30th.
  • All infected dogs that have been identified in the latest cluster have  close ties to the index site and have been from one area. One of these dogs left the region but has (hopefully) been kept quarantined for 28 days (as have the rest of the infected dogs).
  • Most of the infected dogs that we have been able to follow serially (i.e. test multiple times) are no longer shedding the virus.

We can’t call this over yet, since our last new case was October 30. Dogs can shed the virus for a few weeks after infection (even if they look healthy). Currently, we use 28 days as the potential shedding period. So, we’re looking at ~November 26 as the end of the window for the last known case. I tack on a week or so to give us time to find any cases that might have been infected at end of that period. Odds are quite low at this point that there will be more transmission from this outbreak, but we need a bit more time and testing to be sure. By early December, we can hopefully declare this over.

This is hopefully another example of our ability to eradicate this highly infectious virus with astute primary care veterinarians, quick testing, good communication and responsible owners who will quarantine infected animals. I’m always wary of speaking to soon (or jinxing it), but it’s important to know this approach can be successful. It’s not often done (explaining why flu continues to spread in some regions) but with some effort, diseases like this can be contained.

At the same time, the effort required and the potential for such a virus to spread beyond our control can’t be ignored. That’s why we need to be careful when importing dogs from areas where canine influenza is widespread.