Canine Influenza Virus: Information for Dog Owners

Canine influenza virus (CIV) is a viral respiratory infection found primarily in dogs but which can also affect cats. There have been two identified strains of the virus in the US: H3N8 and H3N2. These viruses are considered to be endemic in the United States.


In February 2018, a case of H3N2 canine influenza has been confirmed in a Grants Pass dog. A 7 year-old male Yorkie had traveled to Reno, Nevada with its owner where the dog was exposed to a known case of canine influenza. The dog will remain quarantined for 30 days. The dog is recovering.

This is the first confirmed case of this strain of the virus in Oregon, and follows an outbreak of the same strain in northern California and Reno, NV.

The Oregon Veterinary Medical Association, the Portland Veterinary Medical Association, and the Public Health Veterinarian, Dr. Emilio DeBess, recommend proactive vaccination of at-risk dogs for CIV (both H3N2 and H3N8 strains).

Dogs in close contact with infected dogs in places such as kennels, groomers, day care facilities, shelters and rescues are at increased risk of infection. Dogs with pre-existing heart disease or lung disease, some senior dogs, and brachycephalic breeds may also be at risk. Vaccination of veterinary staff dogs is advised, as transmission can occur via fomites, such as clothing.

Cats have been confirmed to have been infected with the H3N2 virus; however, the risk to most cats living outside of shelters is considered low, with the highest risk factor being infection in a household dog, so prevention of illness in dogs is key to the health of other animals in the household. There is some evidence that guinea pigs and ferrets can become infected.


According to the Centers for Disease Control, the first evidence of H3N8 canine influenza in companion dogs was documented in spring 2005. It is believed to have jumped species from horses and was first identified in an outbreak of respiratory illness in racing dogs in Florida in 2004. H3N8 does not affect cats. Since the virus was identified in 2005, Oregon has had a few documented H3N8 cases.


Canine influenza is an airborne disease, much like kennel cough (Bordetella bronchiseptica). The virus can travel in droplets from a cough or sneeze and can be transmitted by contact with contaminated objects (for instance, a chew toy).

Practically speaking, if your dog stays at home and rarely contacts other dogs, its risk of contracting the virus is likely low. If your dog is boarded, goes to day care, or the dog park, it may be at a higher risk.

If your dog is coughing, it should not go to public places where it could contact other dogs until your veterinarian agrees it's safe for your dog to go out.


The most common clinical signs are coughing, loss of appetite, lethargy, fever, sneezing, and discharge from the eyes and/or nose. Dogs can become ill within 24 hours of exposure. Some dogs don’t show symptoms, but are able to infect other dogs for weeks. Most dogs diagnosed with canine influenza experience a mild form of the disease.

Call your veterinarian if your dog develops a cough, especially if it has already received the Bordetella vaccine. If your dog is coughing, do not take it out to locations where it may infect other dogs. Early intervention is key to limiting community outbreaks.

Be sure to tell your veterinarian if your dog has been boarded, sent to the groomer or involved in any social activities (dog park, day care, etc.) within the last month.

Remember, coughing can be indicative of a variety of significant diseases or conditions. Your veterinarian is best qualified to diagnose your dog.


After handling a sick dog, wash your hands before touching your dog. Avoid contact with dogs that appear sick.

Vaccines are available for both the H3N8 and H3N2 strains. Discuss your dog's specific risk factors with your veterinarian to determine whether vaccination against canine influenza is appropriate for your pet.

If your dog goes to day care or if you plan to board your dog, vaccination may be recommended. You should check in advance to see if the vaccination is required at these facilities. The Bordetella vaccine does not protect dogs against canine influenza.

Updated: 2018-02-16 08:00:00

Sources: Information compiled from a variety of sources, including the AVMA, Oregon Public Health Veterinarian's office and the CDC.