Worms & Germs Blog

Canine Influenza update and fact sheet

Posted in Dogs, Vaccination

The recent H3N2 canine influenza cluster in Ontario is hopefully still contained. Some infected dogs continue to shed the virus, but a good thing about flu is that there’s no long-term carrier state. Dogs will typically shed the virus for a couple of weeks, but then it should be gone. Accordingly, if the affected dogs (imported dogs and the household contacts they infected) can be contained for a few weeks, it’s possible that it can be eradicated from the area.  However, with the amount of ongoing cross-border dog traffic, we must always be vigilant for new incursions.

Here’s our updated H3N2 influenza infosheet for veterinarians.

Dog parks and canine leptospirosis

Posted in Dogs, Vaccination

A Fremont, California dog park was temporarily closed in response to concerns about canine leptospirosis after 4 reports of dogs contracting the disease, potentially associated with exposure at the park. It’s always hard to determine the source of exposure with lepto, but a park is certainly possible. We don’t understand a lot about how and where most dogs get exposed because it’s a somewhat challenging bug to track. Certainly, parks provide great mixing grounds for dogs and wildlife (the latter being the main reservoirs of the bacterium).

What to do with a potentially contaminated park area is a common question (without a good answer). Fremont Parks Supervisor Juan Barajas indicated to NBC Bay Areathat workers have briefly shut down the park and are working on extra sterilizations using diluted bleach on all the surfaces, including the astroturf. This is the first time the infection has been associated with the park and as a part of a new policy, there will be thorough cleanings and sterilizations four times a year.”

I appreciate the sentiment, but doubt this will do much to control disease spread. For one thing, you can’t effectively disinfect the outdoor environment. Bleach gets inactivated readily in the presence of organic debris (e.g. dirt). You can disinfect smooth surfaces and maybe the astroturf, but those aren’t likely the main problem. Leptospira bacteria get into the environment via urine of infected animals, predominantly wildlife. Even if you could sterilize the environment, if infected wildlife are present (which is almost certainly the case), contamination will recur very quickly. Thorough cleaning is never a bad idea, but I don’t expect this to do much to protect against lepto. The most important things that Fremont Parks can do are to spread the word about the potential risk of lepto and encourage dog owners to vaccinate their dogs against this nasty disease.

Canine flu update: Ontario

Posted in Dogs

After identification of H3N2 canine influenza in two recently imported dogs in Ontario, testing of a group of in-contact dogs was performed. Five more infected dogs were identified, including both dogs that developed signs of influenza and those that stayed healthy. Infection of these animals was expected since these dogs were in close contact with the index cases, and canine influenza is highly transmissible between dogs.

At this point, there is no evidence of any transmission beyond the initial household contacts. The affected dogs have been voluntarily confined, and since influenza virus shedding is transient, it is hoped that this has been contained. The affected dogs continue to be monitored and there is no evidence that other dogs have been exposed.

Click here for the Windsor-Essex Health Unit press release.

Canine flu vaccination: Canada

Posted in Dogs, Vaccination

Not surprisingly, “should my dog be vaccinated against flu?” has been a very common question over the past few days. Here’s my take on vaccination of Canadian dogs, with the assumption that the recent H3N2 flu cluster in southwestern Ontario has been contained (something that is likely but is still to be determined).

Who should be vaccinated?

  • Dogs that will be travelling to areas in the US where there is canine flu activity (or more broadly, dogs that travel to the US, since canine flu is present in various regions).
  • Dogs that may have contact with dogs imported from Asia. This includes mainly dogs in rescues and kennels that are actively importing dogs, as well as dogs in households of people thinking about adopting a dog from Asia.
  • Dogs that may have contact with dogs imported (or travelling) from the US. The risk here is lower, but if dogs are coming from US shelters, in particular, it’s not a bad idea to vaccinate the dogs that will have contact with them.

When else might vaccination be useful?

The benefits of vaccination decrease as the likelihood of exposure decreases. There are a few more groups where vaccination could be considered:

  • Dogs at increased risk of exposure. This includes dogs that have frequent contact with lots of other dogs, especially dogs from a wide geographic range, such as those that travel for shows or other similar events.
  • Dogs at increased risk of serious consequences. This includes dogs with pre-existing heart disease or lung disease, potential senior dogs, and brachycephalic breeds (i.e. smushy faced dogs like bulldogs).

What about everyone else?

On one hand, it’s easy to say that the risk of exposure is very low, so vaccination is of very low utility (because it’s true). The tricky part is the fact that you never know when (and it’s probably when, not if) canine flu will revisit Canada. It takes two doses of vaccine given a couple of weeks apart for good vaccine effectiveness, so by the time a problem is identified, dogs in the immediate area may already be exposed before vaccination has time to work.

That’s an inherent problem with emerging diseases.

H3N2 canine flu could pop up in any given city tomorrow, but it also might not happen for years. At the moment, it’s hard to say that vaccination is broadly indicated in Canadian dogs, but if people are particularly worried about flu, it’s a safe vaccine and there’s no reason not to get it.

What about my dog, Merlin?

He’s pretty low risk. We live in the country and he doesn’t see other dogs at home. However, he goes into work with Heather regularly and mixes with a few other dogs there. It’s a fairly small population, but those dogs presumably regularly meet other dogs (who meet other dogs…), so if flu emerged in this area, he’d be at some degree risk. At the moment, I don’t have a plan to vaccine him against flu. (Leptospirosis is a different story. He’s getting that booster tonight.)

More information about canine influenza can be found here.

Canine flu: What are the human health risks?

Posted in Dogs

Now that canine flu has been identified in Ontario, I’ve been inundated with questions, including “what is the risk to people?” It’s often tough getting the right message across, since there are some potential human health risks, but they are very low. The fact that we can’t say “it’s not a concern” sometimes gets taken as meaning “it’s a big problem.” Yes, there are some things to be concerned about, and that’s why we pay attention to flu. Yet, a lot of things have to happen for this to be a realistic public health concern. See the video below for more discussion of this (and yes, I know… I’m far from an expert videographer).


Canine Influenza: Ontario

Posted in Dogs

H3N2 canine influenza has been identified in two dogs in Essex County, Ontario. The dogs were imported from Asia (via the US) in late December and were showing signs of respiratory disease the following day when they were examined by a veterinarian. A small number of dogs that had close contact with the affected dogs also have mild respiratory disease, but test results from those animals are not yet available.

This is the first known incursion of H3N2 canine influenza in Canada. The virus is widespread in some parts of Asia and is causing outbreaks in various locations in the United States, especially in shelters. Canine influenza virus is of concern because it is highly transmissible between dogs, particularly in areas (such as Canada) where dogs do not have natural immunity from previous infection and where canine influenza vaccination is rare.

A few important points should be noted:

  • Most dogs that develop influenza do not get seriously ill. Respiratory disease that is indistinguishable from other infectious respiratory diseases (canine infectious respiratory disease complex, also known as ‘kennel cough’) usually occurs, although serious (including fatal) infections and/or complications can develop.
  • Infected dogs can shed influenza virus for a short time prior to the onset of disease. So, dogs that appear to be healthy are still a potential source of infection.
  • Canine influenza vaccines are available from veterinarians in Canada. Like human flu vaccines, they do not guarantee protection but they reduce the risk of disease.
  • Cats can be infected but this appears to be rare.

Canine H3N2 influenza virus is different than the human H3N2 influenza virus that is a common seasonal flu virus in people. There is no known human risk from H3N2 canine influenza virus; however, the risk of reassortment (or mixing together) between the canine H3N2 virus and human seasonal influenza viruses is a potential concern. As influenza in animals is a reportable disease, the Windsor-Essex County Health Unit, the Ontario Ministry of Health and Long-Term Care (MOHLTC) and Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) are involved in the investigation, along with the University of Guelph.

The investigation and response are ongoing, and at this point, the concern mainly involves the imported dogs and their close contacts. Affected and exposed dogs are being confined by their owners to help prevent further spread. However, dog owners in the Essex County area should be vigilant and watch for signs of respiratory disease in their dogs, particularly dogs that frequently have contact with other dogs.

Because canine influenza virus (as well as other infectious causes of respiratory disease) can be highly contagious, care must be taken with sick dogs. Dogs with signs of respiratory disease (e.g. cough, decreased appetite, nasal and eye discharge, fever) should be kept away from others dogs for at least 3 weeks. If a dog with potentially infectious respiratory disease is taken to a veterinarian, the veterinary clinic should be informed in advance so that they can take appropriate precautions, such as admitting the dog directly to an examination or isolation room and using isolation precautions.

More information will be provided as it becomes available.

An H3N2 Canine Influenza Information Sheet for veterinarians can be found here.

US rabies map: 2017

Posted in Cats, Dogs, Horses, Rabies, Vaccination

We track a few different diseases, both for research and for general education, including rabies. The maps below provide an overview of rabies in dogs, cats and horses in the US in 2017. It’s not a complete representation of cases, since we don’t have access to everyone’s surveillance data. It’s compiled through monitoring various reports and new articles. Looking at published reports from the past few years, I’d guess we get ~30-40% of cases.  However, while it’s not a 100% capture of rabies cases, the maps still show a few noteworthy things:

  • Cats are the most commonly infected domestic animal when it comes to rabies. That is probably because of a combination of large numbers of roaming cats and relatively poor rabies vaccine coverage.
  • Most rabies reports that we found were from the eastern US. Whether that’s a reflection of more disease, more surveillance or more widespread reporting si unclear. It could be a combination of all of those.
  • Rabies was much less common in dogs than in cats, but the risk in dogs can’t be ignored since they are more likely to be household pets than cats (since many of the infected cats are feral) and that means there’s probably a much greater chance of human exposure.

There are a number of things can be done to reduce the risk of rabies exposure, and limiting roaming of pets and their contact with wildlife are important. However, it’s virtually impossible to completely prevent rabies exposure risk, so vaccination is critical. Rabies vaccination is cheap and highly effective, and still underused.

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

When bugs don’t read the books

Posted in Cats, Dogs

Minus 20C weather is supposed to have some benefits – at least that’s what we try to tell ourselves. (Maybe we’re just trying to justify why we haven’t migrated south.)

I’ve written about leptospirosis a few times recently, given the horrible lepto season we’ve been having. This bacterial disease isn’t new, but there have been two big differences this year: one was the number of cases, which was well beyond what we’ve ever seen here in Ontario; the other was the timing of cases. I’ve been saying, for weeks, that the lepto season has to be over soon. The bacterium is shed in urine of certain wildlife hosts and likes wet – but not frigid – environments. Yet, we’re still seeing new cases.

  • We’re currently trying to figure out why this is, but I guess the key message I have for people at this point is “vaccinate,” since avoiding exposure is tough when we really don’t understand the main exposure risks.
  • The other thing is to consider lepto in sick dogs, even this time of year. Rapid treatment is important for management of this potentially serious disease, and it’s easy to understand how it would be overlooked in late December, since it’s considered a fairly seasonal disease.

Another area we’re working on a lot is tickborne diseases. The general dogma regarding ticks is that the will begin to quest (search for a host) when the temperature hits at least 4C. That’s a distant memory around here, as it hasn’t been above -10C in a while. Yet, I got a report from a reader about a feral cat carrying engorged ticks, from an area north of here that’s snow covered and even colder than here (currently sitting at -27C). It’s been well below freezing there for a long time, and well beyond typical adult tick attachment times. So, where did this cat pick up a tick? Maybe in a warm area such as a barn? Or, is 4C not really the right threshold.  It’s probably a matter of some ticks finding warmer microenvironments and cats seeking out those same warmer (or less cold) spots.

  • Regardless, this reinforces the message we’ve been saying: even in many cold climates, tick exposure is a 12-month-a-year risk. Even using the 4C threshold, it’s not unusual to get a few few days of 4C weather in the middle or winter around here. If the exposure threshold is even lower (or irrelevant if ticks can be questing in some isolated, warmer locations during cold periods) then even that gets tossed out the window.
  • For lepto, the main message is “vaccinate and be aware.” For ticks, it’s “use tick prevention and don’t stop tick-checks.” The risk is presumably quite low in winter, but low doesn’t mean zero, and tick avoidance practices aren’t particularly hard or expensive.

I guess I need to come up with a different “on the bright side…” excuse for this weather.

Armadillos, vacations and leprosy

Posted in Other animals

It’s easy to get hung up on odd ball reports, since they’re interesting and novel. Their overall impact is pretty low, but they often have some reasonable take-home messages.

So, here’s another odd ball report: leprosy in a Canadian who had never traveled beyond Canada and the US (Bonnar et al, 2018 Emerging Infectious Diseases).

Leprosy is a nasty disease, caused by the bacterium Mycobacterium leprae, that many people think of only in historical terms (see photo). Yet, it continues to cause problems in some regions of the world.

The reported case involves a man from Atlantic Canada who was diagnosed with Hansen disease (leprosy). It took some time to arrive at the diagnosis, not surprisingly, since he had no history of travel to an area where leprosy is common, so it wasn’t likely high on the list of potential causes of disease. His travel history only consisted of annual trips to Florida.

Molecular analysis of M. leprae from the man found that it was consistent with a zoonotic strain of the bacterium that is found in armadillos (or, more specifically, 9-banded armadillos). No contact with armadillos was reported, but indirect transmission is suspected to have occurred, such as through contact with environmental sites.

This doesn’t mean people should avoid travel to Florida. However, it highlights a few issues:

  • Travel history is important for diagnosis of some infectious diseases. Physicians need to ask, patients need to offer the information, and, importantly, physicians need to know (or have good resources for) what diseases to suspect in different areas. (Leprosy risk from armadillos probably isn’t commonly known.)
  • Travel history doesn’t just include long trips or exotic locales. Any travel to a different region can result in different risks. Some people don’t say “yes” to the travel question for what they consider to be routine travel, such as yearly trips to Florida from Canada. From an animal standpoint, we run into this when people don’t consider visits to the family cottage as “travel,” even though there may be very different disease risks at the cottage compared to the city.
  • While direct armadillo contact wasn’t reported here, limiting contact with wildlife is a good idea, and any time there’s any contact, hand hygiene shouldn’t be forgotten.