Canine Infuenza Virus: A Cause for Concern?

August 28, 2018

As you may have seen in the news, three cases of canine influenza virus (CIV), or “dog flu”, have been diagnosed in Massachusetts this month. Based on the very small number of dogs currently infected, we don't consider this to be an outbreak yet, but believe that dog owners in Massachusetts need to be aware of the disease. Read on for more information on the canine influenza virus and a brief primer on when to consider vaccinating your dog. 

What is Canine Influenza (CIV)?

Canine Influenza is a variant of the bird flu that causes signs of respiratory infection in dogs. Transmission generally requires direct contact with an infected and contagious dog's fresh saliva or oro-nasal secretions. The disease is highly contagious (nearly 100% of dogs that come in contact become infected), but rarely fatal. Dogs are at highest risk in confined spaces like shelters, day care centers, groomers and boarding kennels. Unfortunately, an infected dog is usually contagious before showing any symptoms of the disease. Therefore, even dogs that appear healthy can transmit the disease.

What are the signs?

There are two forms of CIV: One that is mild, and one that is more severe and accompanied by pneumonia.

Mild form: 

Signs of the mild form of CIV are almost identical to the typical “kennel cough”, but last longer. Dogs suffering from this form of 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.

Severe form:

Dogs with the severe form of influenza develop high fevers and have clinical signs of pneumonia, such as increased respiratory rates and effort. Fatal cases of pneumonia resulting from infection with influenza have been reported in dogs, but the fatality rate is less than 10 percent. Even dogs with the severe form usually recover in two to three weeks, but often require intensive treatment and hospitalization. Very young dogs and seniors (who may have compromised respiratory systems or concurrent diseases associated with age) may be more likely to have severe signs of illness.

When should I see the veterinarian?

If your dog develops a cough or thick nasal discharge, especially if they are feeling sick, please schedule an appointment to be seen. If your dog has these symptoms, please avoid all contact with other dogs until a diagnosis has been made. Because CIV is so contagious, we will likely ask you to wait in the car until your appointment time or escort you immediately into a room to wait.

Should I vaccinate my dog for CIV?

At CVH, we carry the vaccine that covers both the H3N2 and H3N8 strains of CIV. The vaccine is approximately 60 percent effective, so it may not prevent infection with CIV, but will reduce the symptoms in most dogs. Dogs require 2 vaccines spaced 2-4 weeks apart and are not considered protected until after the second vaccine.

The risk of exposure to CIV in Massachusetts is still very low, but owners of high risk dogs should consider vaccination. This includes dogs that travel to endemic states (Midwest, CT, NY), come into contact with large numbers of dogs indoors, attend dog shows, or are immunocompromised.

If you feel that your dog is at high risk for contracting CIV and your pet has been seen at CVH in the past 12 months, please call to schedule a technician appointment to begin the vaccine series. If you are considering the vaccine but would like to discuss it with a doctor, or if your pet is not current on other vaccines, please call to make an appointment with one of our doctors.

For the most current information available about the spread of the disease, visit for realtime tracking of influenza cases in the United States.

Wishing your pet families happiness and good health,

The Doctors and Staff at Commonwealth Veterinary Hospital