Canine Influenza in Canada – A New Cluster

Ontario canine flu update: March 10

Active canine influenza cases are still known to be present in two regions in Ontario.


  • A small number of dogs from the initial cluster of cases in the Orillia/Bracebridge/Gravenhurst region are still shedding the virus, as expected given this virus can be shed by some dogs for a few weeks. The dogs that made up the earlier cases should be done shedding soon, hopefully decreasing the pool of infected (and infectious) dogs.
  • Surveillance is still underway to detect new clusters.
  • At this point, we have not seen rapid expansion since the problem was first identified and containment measures were implemented. We would like to continue to test dogs in this area that develop signs consistent with influenza (e.g. cough, runny eyes, runny nose). This is particularly true for dogs with known contact with confirmed influenza cases, but testing of any dogs with flu-like disease is desirable to detect new clusters and make sure we know the extent of the problem.

Northumberland County ( Coburg Area)

  • Multiple cases are present in this area, all currently linked to one source.
  • How H3N2 influenza got to this region is still being explored, and while I have some ideas, we do not yet know for sure. It may be indirectly linked to the Muskoka cluster, but this has not yet been confirmed.
  • As in Muskoka, testing of contacts of dogs with influenza, as well as other dogs in the area with flu-like disease is underway. Owners of local dogs that develop these signs should contact their vet to discuss testing, as we want to determine the extent of the problem and try to contain it.


  • No positives were identified in our round of testing Friday. No known active cases are present in the region at the moment.
  • It is strongly suspected that canine influenza was the cause of disease in a couple of clusters of dogs; however, sampling was late enough that we might have missed active shedding. While that complicates our investigation of the spread, it’ s good news in that we don’t have known infectious dogs in the area.
  • Hopefully the small clusters of disease that were likely flu have been contained and this area is now flu-free. However, as with the other regions, we want to continue to do some testing in case there are still cases in the area.

Other areas of Ontario

  • We are testing a smaller number of dogs from other areas, with no known link to the affected regions. This is low yield because we don’ t expect influenza to be present (but I didn’ t expect it to be present in the Muskoka group either). This testing will be continued in the short term to try to make sure we do not have other clusters (associated or not).
  • We had hoped that control of the two recent clusters of H3N2 canine influenza in Windsor-Essex, Ontario, meant that the province was again free of that virus, another cluster of infections has been identified, this time in Orillia, Ontario. Investigation is ongoing so the number of infected dogs is currently unclear, but as always, introduction of this virus into a population of dogs with no pre-existing immunity from previous influenza exposure or vaccination raises concern that the virus could spread quickly if it gets a foothold in the community.
  • At this time, the source of infection is not known, although a potential link to a rescue that has imported dogs from Asia is being investigated. There is no known link with the earlier Windsor-Essex County clusters. Contact tracing and testing is underway.
  • Dog owners in the Orillia area should be aware, but not paranoid.
  • Here are some key messages (for dogs anywhere, but particularly those in areas where canine flu has been confirmed):
    • If your dog is sick, keep it away from other dogs.
    • If you are out with your dog and see a sick dog, keep your dog away from it.
    • If you have contact with a sick dog, wash your hands (and ideally change clothes) before you touch your dog.
    • Most dogs with influenza get over it on their own. As long as they are bright, alert, eating and don’ t have yellowish nasal discharge, we typically do not provide any specific treatments beyond cough suppressants, if coughing is excessive.
    • If your dog has signs that could be consistent with influenza (e.g. cough, nasal discharge, fever, runny nose or eyes) and you are taking it to your veterinarian, make sure you call the veterinary clinic first so that they can use measures to prevent exposure of other dogs at the clinic (e.g. admitting your dog directly to an exam room or isolation area).
  • If your dog is sick and has been at a kennel, doggy daycare, puppy class, or any other event, contact the owner/operator to let them know. If your dog is diagnosed with influenza or has signs consistent with influenza, it should be kept away from other dogs for 4 weeks (even if it no longer looks sick sooner than this).
  • What to do about vaccination is a common question. Now that we have evidence of three separate canine flu clusters in Ontario, it’ s quite possible that this virus is spreading in different areas of the province. Vaccination is not a guarantee but it can reduce the likelihood and severity of disease. At this point, I think vaccination of high risk dogs in Orillia is justifiable, and that could be extended to anywhere in Ontario since it seems like the virus may be more widespread than we had thought.
  • Dogs that I prioritize for vaccination are:
    • Dogs at increased risk of exposure to the virus
    • Dogs that attend kennels, classes, day cares, shows/competitions and other areas where many dogs mix
    • Dogs that are at increased risk of severe disease if they get infected
    • Elderly dogs
    • Dogs with underlying heart or respiratory disease
    • Bulldogs and other brachycephalic breeds
    • Breeding kennel dogs
  • It’s a fluid situation and more information will be released as it becomes available.

More information about canine influenza in Canada and the US, as well as some of our informational materials, can be found is in the Worms & Germs Archive – Influenza.

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