Canine Influenza Virus (CIV), a highly contagious virus, has been identified in two dogs in Canada. The dogs were imported as part of rescue program and were brought to Canada from South Korea (via the United States) in late December.
Two dogs in Essex County (a community in Southwestern Ontario bordering Detroit, Michigan) have the H3N2 strain of the virus. Several other dogs that were in contact with the affected dogs are showing signs of infection as well, but the H3N2 virus has not been confirmed in these dogs.
There are primarily two strains of influenza that affect dogs: H3N8 (a strain originating with horses) and H3N2 (a strain originating with birds). H3N2 was identified in the United States in 2015 when an outbreak of respiratory illness in dogs occurred in Chicago. Previous to this, the H3N2 virus was only found in Asia. A more recent outbreak of H3N2 was reported in May 2017 in Florida. By mid-June, H3N2 had been identified in many other states including North Carolina, South Carolina, Texas, and Illinois.
While the virus is usually not fatal, it is highly contagious and can cause complications for older dogs or those with existing health problems, or can progress to more serious infections.
What you need to know
Human risk? There is no evidence of transmission of canine influenza viruses from dogs to humans and there are no reported cases of human infection with a canine influenza virus. However, there is a risk for “mixing” of the H3N2 virus and human seasonal influenza viruses. Health officials and infectious disease specialists at the Ontario Veterinary College at the University of Guelph are involved in investigating and monitoring the virus closely. CIV poses a low threat to human health.
Spread of disease. Canine influenza virus spreads easily among dogs. CIV is spread by airborne respiratory secretions (coughing and sneezing) and from contaminated objects such as food and water bowls, kennel floors and walls, collars and leashes, and from the clothing or skin of people who have had contact with infected dogs.
Incubation time. It takes 2-4 days for signs to appear after contact with the virus. Infected dogs are most contagious during this incubation period, spreading the disease before symptoms show. Infected dogs continue to spread the virus for up to 20 days. Dogs that have been exposed to the virus should be isolated (no walks, dog park, grooming, doggy daycare, etc.) for 4 weeks to prevent spread of the disease.
Signs your dog may have CIV. The signs of H3N2 include cough, runny nose, fever, lethargy, eye discharge, and reduced appetite; however not all dogs show these signs. The severity of the illness can range from no signs to severe illness that can progress to pneumonia. Most dogs will recover in 2-3 weeks, but some dogs may develop secondary infections that can lead to severe illness.
What to do? If your dog is showing any signs of the virus, call your veterinarian in advance and let the clinic know that you suspect canine influenza virus. Because the virus is spread so easily, your veterinarian will need to take precautions to ensure the virus is not spread to other dogs in the clinic.
Testing and vaccines. Tests are available to confirm a diagnosis of the H3N2 (and H3N8) virus. There are vaccines available in the United States and Canada for both strains of the virus. Speak to your veterinarian for additional information about the vaccines. You veterinarian will help you determine if you should vaccinate your dog.
Are cats at risk? Cats can be infected with H3N2, but it is rare.