Canine Influenza

Two clinical syndromes have been seen in dogs infected with the canine influenza virus—a mild form of the disease and a more severe form that is accompanied by pneumonia. If your dog shows any of these symptoms it is recommended you contact your family veterinarian for care and advice.

Mild form — Dogs suffering with the mild form of canine influenza develop a soft, moist cough that persists for 10 to 30 days. They may also be lethargic and have reduced appetite and a fever. Sneezing and discharge from the eyes and/or nose may also be observed. Some dogs have a dry cough similar to the traditional "kennel cough" caused by Bordetella bronchiseptica/parainfluenza virus complex. Dogs with the mild form of influenza may also have a thick nasal discharge, which is usually caused by a secondary bacterial infection.

Severe form — Dogs with the severe form of canine influenza develop high fevers (104ºF to 106ºF) and have clinical signs of pneumonia, such as increased respiratory rates and effort. Pneumonia may be due to a secondary bacterial infection.

The percentage of dogs infected with this disease that die is very small (less than 10%). Some dogs have asymptomatic infections (no signs of illness), while some have severe illness with infection. Severe illness is characterized by the onset of pneumonia. Most dogs recover from illness in 2-3 weeks.

Canine influenza H3N8 viruses originated in horses, spread to dogs, and can now spread between dogs. H3N8 equine influenza (horse flu) viruses have been known to exist in horses for more than 40 years. In 2004, cases of an unknown respiratory illness in dogs (initially greyhounds) were reported in the United States. It has now been detected in dogs across most of the United States.

Canine influenza H3N2 viruses originated in birds, spread to dogs, and can now spread between dogs. Transmission of H3N2 canine influenza viruses to cats from infected dogs has been reported also. Canine influenza A H3N2 viruses were first detected in dogs in South Korea in 2007, and have been reported in dogs in China, Thailand, and Canada. H3N2 canine influenza viruses were first detected in the United States in April 2015, and has now been found in more than 30 states.

Canine Influenza spreads through direct contact with infected dogs or cats. It can also spread through the air when an infected dog coughs, barks or sneezes. Dogs infected with Canine Influenza can be contagious for up to 30 days. The virus can survive 1-2 days on floors and cages. Vaccination for Canine Influenza is recommended for dogs that are around other dogs such as dog parks, boarding facilities or the groomer.

Consult your veterinarian. Coughing can be caused by many different medical problems, and your veterinarian can examine and evaluate your dog and recommend an appropriate course of treatment. If canine influenza is suspected, treatment will usually focus on maximizing the ability of your dog's immune system to combat the virus. A typical approach might include administration of fluids if your dog is becoming dehydrated and prescribing an antimicrobial if a secondary bacterial infection is suspected.

While there is currently no reliable rapid test available to veterinarians for diagnosing canine influenza, tests are available at certain diagnostic labs. For more information, contact your local veterinarian.

In general, canine influenza viruses are thought to pose a low threat to people. To date, there is no evidence of spread of canine influenza viruses from dogs to people and there has not been a single reported case of human infection with a canine influenza virus in the U.S. or worldwide.

 Take your dog to see your Veterinarian to get vaccinated against canine influenza. There is no vaccination available for cats.

If you think your pet has canine influenza, keep it away from other pets and contact your veterinarian right away.

Vaccination against other pathogens causing respiratory disease (such as Bordetella, adenovirus and parainfluenza) may help prevent more common respiratory pathogens from becoming secondary infections in a respiratory tract already compromised by influenza infection.

More information on canine influenza in pet dogs can be found at the following links:

• Influenza A Virus (H3N8) in Dogs with Respiratory Disease, Florida (Emerging Infectious Diseases)
• American Veterinary Medical Association: https://www.avma.org/resources-tools/animal-health-and-welfare/canine-influenza
• Center for Disease Control and Prevention (CDC): https://www.cdc.gov/flu/other/canine-flu/keyfacts.html
• https://www.dogflu.com/