Fact Sheet

Home / Fact Sheets / Canine Influenza

Canine Influenza

The Facts

  • Canine influenza is an upper respiratory infection in dogs caused by the H3N8 Type A influenza virus.
  • It is a very new disease that is believed to have mutated from an equine influenza virus at a racetrack in Florida in 2004.
  • The first outbreak was in racing greyhounds in Florida, but the disease has quickly spread across the country, and has now been diagnosed in 34 states and the District of Columbia. Outbreaks are most common in animal shelters, boarding kennels and doggie daycare facilities.
  • The virus is highly contagious and can be transmitted via airborne droplets produced from coughing and sneezing, as well as via contaminated surfaces, hands and clothing.
  • Good cleaning and disinfection practices can help control the spread of canine influenza, but they cannot totally eliminate it from the environment.
  • Several other diseases can produce the same clinical signs as canine influenza, including kennel cough (caused by Bordetella bronchiseptica), parainfluenza, andenovirus and canine herpes virus.


Most cases of canine influenza present as mild upper respiratory infections with coughing, nasal discharge, low-grade fever, lethargy and decreased appetite. In some cases, the cough may persist for several weeks. About 20 percent of cases will develop more severe symptoms, including high fever and pneumonia. These severe cases are most often due to a secondary bacterial infection. About 5-8 percent of pneumonia cases result in death.


  • If your dog has any of these symptoms, see your veterinarian. Your vet will need to do laboratory tests to confirm a diagnosis of canine influenza. He or she may prescribe antibiotics or more intensive treatment if warranted.
  • Make sure your dog has a quiet area in which to rest. Keep him away from other pets and children, and keep play and exercise to a minimum until he has fully recovered.
  • Keep your dog indoors and away from other dogs to prevent the spread of the disease.


In 2010, the U.S. Department of Agriculture fully approved a vaccine for canine influenza. If you will be taking your dog to a groomer, boarding kennel, dog park or any area where he will come in contact with other dogs, ask your veterinarian about this vaccination.

Important to Know

Symptoms such as fever, severe lethargy, decreased appetite, yellowish nasal discharge or difficulty breathing may be signs of a more serious illness such as pneumonia. If your dog has any of these signs, see your veterinarian right away.

Updated On
August 26, 2016
Related Programs
Fact Sheet Topics

Our first-responders are there when animals need them most

From natural disasters to animal cruelty investigations, we are on the front lines protecting animals in times of crisis.

Contribute Volunteer