Published by: Ingrid King. Last Updated on: February 1, 2023 by Crystal Uys


The canine influenza virus (CIV) that has affected at least 1,000 dogs in Illinois, Wisconsin, Ohio and Indiana in the last month, resulting in five canine deaths, may also be a danger for cats. Previously thought to be caused by the H3N8 strain, which has been circulating in North America since 2004, recent tests from the Wisconsin Veterinary Diagnostic Laboratory (WVDL) and the New York State Animal Diagnostic Laboratory at Cornell University have identified the strain as H3N2.

It is believed that the strain originated in Asia. How it arrived in the United States is not known at this point.

Symptoms of CIV

Both CIV strains can cause persistent cough, runny nose, and fever. A small percentage of dogs will develop more severe clinical signs; some will not show any symptoms at all. Neither CIV strain is related to the highly pathogenic H5N2 avian flu, which was recently reported in a commercial flock in Jefferson County; they are completely different strains that affect separate species.

H3N2 strain has caused infection and respiratory illness in cats

Currently, there is no evidence that either CIV strain is contagious to humans. However, while the more familiar H3N8 strain is not known to affect cats, H3N2 has caused infection and respiratory illness in felines. The University of Wisconsin School of Veterinary Medicine recommends that pet guardians seek veterinary care for dogs and cats exhibiting clinical signs of CIV.


The University of Wisconsin Veterinary Care recommends the following:

    • Wash your hands and change your clothes if you work with or are exposed to sick dogs before handling your own pets at home. Soap and water is very effective at inactivating influenza virus.
    • Call your veterinarian for further instructions if your dog or cat is showing signs of persistent cough, runny nose and fever.
    • While there is a canine vaccine against the H3N8 strain, it is not known whether this vaccine is effective against the H3N2 strain. There is no feline vaccine.

Avoid bringing your dog in close contact with other dogs. If your dog has been in contact with other dogs, avoid bringing her in contact with your cats.

UWVC also offers information and sampling guidelines for veterinarians.

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6 Comments on Canine Flu Virus May Affect Cats

  1. All my cats seem to have a cold or the flu. They are having difficulty breathing,, snuffling, coughing, sneezing, vomiting. I only had one sick cat, now I have 4 others. I can’t afford to take them all to the vet.

  2. Very scary. Is it easy to catch at a vet’s office. I have been taking my kitties for shots and check ups. I have been hearing about it affecting dogs and I live in WI.

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