BAH Menu
BAH fb aaha Image Map
Home Page

Canine Influenza (Dog Flu)

Sore Throat

Canine influenza, or dog flu, is a highly contagious respiratory infection of dogs.

The Florida Department of Agriculture and Consumer Services (link) in coordination with the University of Florida College of Veterinary Medicine, (link) has confirmed several cases of canine influenza in North and Central Florida. Currently, two strains of the virus have been confirmed in the US:  H3N8 and H3N2.

Canine influenza can be mild or severe. Clinical signs of infection for H3N8 usually appear in 1 to 5 days, while those infected with H3N2 my start showing signs between 2 and 8 days. The severity can range from no signs to severe illness. Most dogs recover within 2-3 weeks, however they can remain contagious to other dogs for up to 4 weeks. Canine influenza may persist in the environment for approximately 2 days, and on clothing for up to 24 hours. The virus appears to be easiy killed by disenfectants commonly used in veterinary hospitals and shelters. The percentage of dogs infected with this disease that die is very small.

  • Mild form- a soft, moist cough that persists for 10 to 30 days. Dogs may also be lethargic, have reduced appetite and a fever. Sneezing and discharge from the eyes and/or nose may also be observed. They may also have a thick nasal discharge.
  • Severe form- may develope a high fever and have clinical signs of pneumonia. Pneumonia may be due to a secondary bacterial infection.

So far, there is no evidence that canine influenza infects people, but it can infect cats. Symptoms in cats include sneezing and nasal discharge, but usually there is no cough. There is no vaccine for cats.


Almost all dogs, regardless of breed or age, lack immunity to canine influenza and are susceptible to infection (80%) (link) with a majority exhibiting a mild form of the disease.

We have a combo (Bivalent) canine influenza vaccine available. Although vaccinated dogs can still get infected, the symptoms will be less severe and they can recover in a shorter time period. Two initial doses of the vaccine are needed, 2-3 weeks apart. It takes 2 weeks after the second dose to reach full effect. An annual booster is needed to maintain immunity.

Should you Vaccinate?

French Bulldog PuppyIndoor dogs with little exposure to other dogs are less at risk. Older dogs and those with heart and respiratory conditions may be at higher risk, as are brachycephalic dogs (those with short, flat snouts) such as Boston terriers, Boxers, Pekinese, Pugs and Shih Tzus.

The canine influenza vaccine is a "lifestyle" vaccine, and is not recommended for every dog. In general, the vaccine is intended to protect dogs at risk for exposure to the canine influenza virus, which includes those that participate in activities with many other dogs or those housed in communal facilities, particularly where the virus is prevalent. Dogs that may benefit from vaccination include those that receive the kennel cough vaccine (Bordetella/parainfluenza), because the risk groups are similar. Dog owners should consult with their veterinarian to determine their dog's risk of exposure to the canine influenza virus and if vaccination is appropriate for their dog.


"Dogs most at risk for exposure are those with a social lifestyle and participate in group events." (link, pdf). Just as kids can pass things around at day care or school, dogs are more likely to be exposed in situations where they come in contact with large groups of other dogs.


"Canine influenza cannot be diagnosed soley by clinical signs (coughing, sneezing and nasal discharge) because these clinical signs are also present with other canine respiratory illnesses. Tests are available to diagnose and identify the strain of canine influenza virus." (Link)

Please call us if you have any questions or concerns.


University of Florida
University of Florida Information for Pet Owners (pdf)
University of Florida video
Department of Agriculture News Release
AVMA Background Information
CDC Information on Canine Flu


Bradfordville Animal Hospital, Alex Steverson, DVM

June 20, 2017