Canine Influenza (Dog Flu) Outbreak in Chicago Area

April 8, 2015 – CDC is aware of reports of a canine influenza (dog flu) outbreak in the Chicago area. Dog flu is a contagious respiratory disease in dogs that does not cause illness in humans. A vaccine against this disease in dogs has been available since 2009. CDC recommends that people concerned about dog flu speak to their veterinarian.

Signs of dog flu infection include cough, runny nose and fever, but not all dogs will exhibit signs. The severity of illness associated with dog flu can range from no signs to severe illness resulting in pneumonia and sometimes death. Tests are available to determine if a dog has been infected, and your veterinarian can tell you if testing is appropriate. You and your veterinarian can also discuss whether vaccinating your dog against canine influenza is indicated.

Dog flu is caused by an influenza A (H3N8) virus that is closely related to an influenza virus found in horses for over 40 years. Experts believe this horse influenza virus changed in a way that allowed it to infect dogs, and the first dog flu infections caused by these viruses were reported in 2004, initially in greyhounds. This virus is now considered a dog-specific lineage of influenza A (H3N8) virus. Almost all dogs can be susceptible to infection, and illness tends to spread among dogs housed in kennels and shelters.

To date, there is no evidence of transmission of dog flu from dogs to people and there has not been a single reported case of human infection with the canine influenza virus.

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