Dog Articles - Dog Flu

Dog Flu

H3N8, also known as the canine influenza virus (CIV), or dog flu, is a respiratory disease that can be contracted by dogs. It is not contagious to humans.

According to the Center for Disease Control and Prevention (CDC), H3N8 has been around for more than 40 years. H3N8 was initially known as the equine influenza virus, occurring in horses. Then, in 2004, greyhound dogs came down with an “unknown respiratory illness” which turned out to be the equine influenza virus. The virus that made these dogs sick is now contagious among dogs and is considered a dog-specific strain. H3N8 is not a seasonal infection; dogs can contract this virus year round.

Some dogs experience no symptoms from this virus, but it does result in severe infections in others. Dogs with compromised immune systems, or with other severe health issues can have serious complications as the result of the onset of pneumonia.  According to the CDC, “about 80 percent of dogs will have a mild form of disease.”

Dog flu has been documented in 30 of the United States, as well as Washington DC. There are presently no confirmed cases of H3N8 in any other country. H3N8 infections are prevalent in Pennsylvania, New York, Colorado, and Florida.

Regarding humans and H3N8, the CDC has stated that “to date, there is no evidence of transmission of canine influenza virus from dogs to people and there has not been a single reported case of human infection with the canine influenza virus. While this virus infects dogs and spreads between dogs, there is no evidence that this virus infects humans.”

-Runny nose.
-Yellow or green discharge from eyes or nose.
-Decreased appetite.
-Shallow breathing.

It is important that dogs who contract H3N8 are kept well-hydrated, and allowed to rest. In the vast majority of cases, the dog flu will clear up on its own. Vets who suspect a developing secondary bacterial infection (which can cause pneumonia) will usually prescribe a broad-spectrum antibiotic.


H3N8 is spread through contact with secretions from the mucous membranes of infected dogs. Infected dogs are contagious for 7-10 days. A dog can also catch h3N8 from contaminated surfaces. Dogs who are showing symptoms of this the flu should avoid any contact with other dogs. They should also avoid contact with locations or objects that will then com in contact with healthy dogs. All objects, including clothing, toys, leashes, hands, bowls and others which come in contact with animals showing symptoms should be cleaned thoroughly before they are allowed to come in contact with other dogs.

There is also a vaccine for H3N8. In most cases it does not completely protect dogs from H3N8, but lessens the severity of the infection if contracted. The canine influenza vaccine is recommended for dogs who spend time in social settings with other dogs, such as kennels, dog parks, and other dog friendly environments; the same environments for which it is suggested that a dog have the bordatella (kennel cough) vaccine. Talk to your vet about whether or not your dog should be vaccinated against H3N8.

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