Worms & Germs Blog

Worms & Germs Blog

Promoting Safe Pet Ownership

Canine Influenza, Ontario: Nov 17, 2018

By Scott Weese on 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 mid October, associated with more importation of dogs from Asia.
  • The last new positive dog was identified October 30.
  • All infected dogs that have been identified have had 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.
  • Most of the infected dogs that we have been able to follow serially are no longer shedding the virus.

We can’t call this over yet, since our last new case was Oct 30. Dogs can shed the virus for a few weeks after infection (including once they look healthy). Currently, we use 28 days as the potential shedding period. So, we’re looking at ~Nov 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 of infectivity. 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 the success of this approach is important to know. 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 it to spread beyond our control can’t be ignored. That’s why we need to be careful when importing dogs from areas where the virus is widespread.

Update: Canine influenza, Ontario (October 30)

By Scott Weese on Posted in Dogs

Things have been quiet over the past few days. That’s good news (but always makes me a bit antsy, because I want to be sure it’s because there are no new cases vs we’re just not finding them). Documented infections have been confined to one region, with the exception of a dog that travelled out of the area, and which is (hopefully) being kept under quarantine for 28 days at its new location. We’re still testing and getting negative results, and veterinarians in the area are still looking out for potentially infected dogs, so hopefully the situation is being contained. The next week or so will tell us more, as we continue to test and as initially infected dogs start to eliminate the virus.

At a minimum, we want to go 35 days or so after the last new infection before we say we might be in the clear again. Since some dogs can shed the virus for over 3 weeks, I use 28 days as the upper end of the shedding period. I then tack on an additional week, since it takes some time for a newly exposed dog to get sick and be tested. So, if our last known dog was infected Oct 23 (to pick a random but reasonable date), it could shed until Nov 20. Add on a week, and we get to Nov 27. If there are no new cases by then and we still have excellent surveillance by vets and dog owners, we would suspect that the virus has again been contained. If we find any new cases, the clock restarts each time. (I hesitate to write about containment at this point because it sounds like I’m inviting bad luck, but I get a lot of questions about this).

To contain the current cluster of canine influenza we need:

  • Continued diligence by veterinarians and dog owners
  • Continued testing of exposed dogs and any other suspected cases
  • Compliance with quarantine recommendations so infected dogs don’t pass on the flu to other dogs

So far, so good, but time will tell.

Raw pet food and human salmonellosis

By Scott Weese on Posted in Cats, Dogs, Salmonella

We’ve known for some time that there are human health risks from feeding pets raw meat-based diets. Most of the evidence of this has been anecdotal, as published reports have been sparse. A few better documented reports have started to appear, including the fatal E. coli O157 infection I wrote about recently.

A few days ago, the CDC released a report about an outbreak of Salmonella Infantis infections in the US. It involved 92 people from 29 US starts and was linked to raw chicken products. Raw chicken-based pet food was among the raw chicken products from which the outbreak strain was isolated, and one person got sick after their pets ate chicken-based raw food.

This isn’t particularly surprising since Salmonella contamination is an inherent risk with raw poultry. Human disease can occur when people ingest Salmonella from undercooked meat or from contamination of their hands or environmental surfaces (e.g. in the kitchen). When it comes to raw pet food, people can be exposed from handling the food, cross contamination of food or surfaces, contamination of the food bowl or exposure to Salmonella in in feces of the pet.

CDC’s recommendation is pretty straightforward: “CDC does not recommend feeding raw diets to pets. Germs like Salmonella in raw pet food can make your pets sick. Your family also can get sick by handling the raw food or by taking care of your pet”.

I have the same recommendation, but am realistic enough to know that it’s still going to be done by some people. It definitely shouldn’t be done in households with very young, very old, pregnant or immunocompromised people or animals.

If you are going to feed raw diets to your pet, do it wisely. More information about this is available on the Worms & Germs Resources – Pets page.

Update: Canine influenza, Ontario (October 25)

By Scott Weese on Posted in Dogs

As expected, a few more cases have been identified in the most recent cluster of canine influenza virus (CIV) identified in Ontario. So far, there are about 20 confirmed or suspected cases. To date, we’re still only finding cases that have a link to another infected dog or facility. That’s good news. If we start getting cases of unknown origin and/or cases outside the currently affected area, I’ll be more concerned (specifically about the prospects of containing the cluster). A couple of dogs that were potentially exposed and left the area already are being tracked.

Continued diligence by pet owners and veterinarians will help contain this virus. The key is finding all the potentially infected (and infectious) dogs, testing them and keeping them quarantined until they’re no longer a risk to others.

A 28 day quarantine is recommended because of the potentially long shedding period of this virus. In the previous outbreak (as in this one), we sampled positive dogs repeatedly, and some shed the virus for over 3 weeks. So, even a 28 day quarantine doesn’t leave a lot of cushion, but the longer the quarantine period, the greater the risk of non-compliance. Getting people to keep their dogs away from other dogs for 28 days often isn’t easy to do. We like to complain about the weather in Canada, but it will probably help in this situation. It’s forecast to be few degrees above freezing with mixed precipitation over the next few days, something that may help keep dogs from congregating outdoors, buying more time to sort out the problem.

More details to follow.

CDC didn’t actually say “don’t dress up your chickens for Halloween”…but don’t do it anyway

By Scott Weese on Posted in Other animals, Salmonella

Lots of media reports have been saying that the US Centers for Disease Control and Prevention have warned people not to dress up their chickens for Halloween.

  • Yes, chickens.

I wouldn’t have thought that policing chicken fashion would be high on the CDC’s to-do list, but the concern is obviously related to the perpetual outbreaks of salmonellosis linked to chicks and pet poultry.

Did CDC actually say it?

  • No.

Does that mean they disagree?

One concern is the risk to chicken owners. A bigger concern is the likelihood that a fashionably dressed chicken out for Halloween would be encountered and handled by many other people, particularly young kids (a high risk group for infection with Salmonella).

If you want to dress up your chicken for Halloween, go for it, I guess. Just wash your hands and keep others away, or at least make sure they also wash their hands after touching the chicken.

Basically, handle bespoke chickens like raw chicken – you don’t need to run screaming from the room, but do take some basic precautions to reduce the risk of contamination (of yourself and other surfaces or objects) and wash hands (or use a hand sanitizer) to get rid of any harmful bacteria that are transferred.

Image from: https://www.dailymail.co.uk/health/article-6307585/CDC-warns-against-dressing-pet-chickens-Halloween-costumes-salmonella-fears.html

Raw pet food and human illness

By Scott Weese on Posted in Cats, Dogs

Human health risks from raw pet food (either from exposure to pathogens in the food or in the feces of pets eating the food) are known to exist but they’re not well characterized. We know that dogs fed raw meat-based diets clearly have increased risk of shedding various pathogens, particularly Salmonella and multidrug resistant E. coli. We know this results in some degree of disease risk in animals and in humans, but the scope of the problem is poorly understood. A recent report from Public Health England provides some more information about the risks associated with feeding raw pet food.

The report is about four people who were infected with E coli O157, a particularly nasty strain of E. coli that can cause serious disease in people.

  • One person developed hemolytic uremic syndrome (HUS), a particularly severe consequence of infection, and died.
  • The four cases involved the same strain of E. coli O157. Three individuals had been exposed to dogs fed a raw meat diet. Tripe was the specific ingredient that was implicated.
  • Samples of raw pet food were collected for testing. All samples from one raw pet food producer were positive for STEC (shiga toxigenic E. coli, the group to which E. coli O157 belongs). A positive test was also obtained from the freezer of one of the affected individuals, and from one sample of raw tripe. It strain isolated from the tripe was a different from the outbreak strain but supported the notion that tripe might have been the cause. It’s not surprising that they couldn’t isolate the outbreak strain from the food, given the lag from the time of exposure of people to the time of sampling of pet food. Contamination is probably sporadic, with different strains contaminating different batches.

Feeding raw meat-based diets is popular, but associated with risks to pets and people (have we said that enough times yet?). My preference is for it not to be done, but I’m realistic enough to know that people are going to do it anyway. So, I focus on two things:

  1. Who should definitely NOT feed raw meat to their pets?
    • Households where pets or people are at increased risk of severe disease, including those where young, old, pregnant or immunocompromised individuals (human or animal) are present.
  2. If raw meat is to be fed, how can the risk be reduced?

Update: Canine influenza, US and Canada (2018 October)

By Scott Weese on Posted in Dogs

While we’re still working on sorting out and containing our latest Canadian outbreak of H3N2 canine influenza, we can look to the south to see the problems this virus is still causing. Flu is still active in a variety of locations in the US. The numbers reported are presumably a marked under-estimate, since it’s based on clinical diagnostic testing. Only a fraction of sick animals tend to be tested, so many unidentified cases are probably occurring alongside the reported cases.

The latest IDEXX Laboratories’ data are displayed below:

Update: Canine influenza, Ontario (October 20)

By Scott Weese on Posted in Dogs

More cases of H3N2 canine influenza have been identified in the province since the virus was re-introduction to central Ontario in the last week. That’s not surprising, since the start of any outbreak investigation is dedicated to figuring out the extent of the problem. Cases identified in the first few days or week reflect things that happened before we knew anything was going on. It’s what happens after the first week or so that’s most important. Ideally, once we know something is happening and start to intervene, new cases decrease and those that are found are found because we’ve traced them from other infected dogs. When new cases occur out of nowhere, we get concerned that we don’t truly know the extent of the issue.

So, at this point, we’re in a holding pattern, waiting for more testing and watching for more cases.

A few key points for everyone to keep in mind:

  • If you live in the affected area (Muskoka region) or visit there with your dog, be on the lookout for respiratory disease (e.g. cough, runny nose, runny eye) in your canine companion. If your dog develops signs that could be influenza, call your veterinarian first – don’t just show up at the clinic. If your dog needs to be examined, your vet will want to take precautions to make sure your dog doesn’t infect other dogs at the clinic.
  • Most dogs with flu develop fairly mild disease that resolves on its own. Some develop complications (e.g. pneumonia) that require treatment such as antibiotics. Rarely, flu can be fatal. Regardless, it’s highly transmissible and can spread quickly in the dog population
  • If you have imported a dog from Asia (or have adopted a dog that was imported in the past month), keep it isolated from other dogs for at least 28 days after arrival. If your dog has been in contact with an Asian import, keep it away from other dogs for 28 days.

Return of canine influenza: Ontario, Canada

By Scott Weese on Posted in Dogs

Canine influenza virus (CIV) has been re-introduced to Ontario, again in the Muskoka region.  Variant typing for the latest case should be available shortly, but in all likelihood this is once again H3N2 CIV.

More details will follow; however, dog owners and veterinarians in this region should be aware of the return of this highly contagious canine virus. Testing of sick dogs and their contacts, as well as quarantine of infected and exposed animals, is important to help contain the virus. The previous introduction in early 2018 was successfully contained through an aggressive response, and the goal is to do the same this time, to prevent establishment of the virus in the dog population.

Veterinarians can check out the Worms & Germs infosheet on H3N2 CIV for more information and tips on basic precautions to help control the spread of CIV at the clinic level.