H3N2 canine influenza has been identified in two dogs in Essex County. The dogs were imported from South Korea (via the United States) 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 of 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 can reduce the risk of disease and are available from veterinarians in Canada.
- 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 cases of novel influenza in animals are reportable to public health, the Windsor-Essex County Health Unit, the Ontario Ministry of Health and Long-Term Care and Ontario Ministry of Agriculture, Food and Rural Affairs 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 Windsor and Essex County 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 and fever) should be kept away from others dogs for at least two 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.
Editor’s note: Information accurate as of January 8, 2018. For local updates consult www.wechu.org. Ask your veterinarian about the benefits of canine influenza vaccine.