Canine Influenza


Paws-itive Press

Canine Influenza

By Cristina Anzures of Anzer Animal Hospital

The recent outbreak of canine influenza in the southeast U.S. has many owners checking their pets for dog flu symptoms.

Canine influenza, or dog flu, is a highly contagious infection caused by an influenza A virus.

Canine influenza is a reportable disease in some U.S. states.

The first recognized U.S. outbreak of H3N2 canine influenza occurred in 2015, starting in Chicago and spreading to other Midwestern states. Since March 2015, outbreaks have occurred in a number of areas throughout the U.S. and thousands of dogs have been confirmed positive for the H3N2 virus. 

Outbreaks are more commonly seen in situations where groups of susceptible dogs are in close contact, such as shelters, kennels, dog day care facilities, and grooming or boarding facilities.

Canine influenza is spread via aerosolized respiratory secretions (via coughing, barking and sneezing) and contaminated objects (kennel surfaces, food and water bowls, collars and leashes) and people moving between infected and uninfected dogs. The virus can remain viable (alive and able to infect) on surfaces for up to 48 hours, on clothing for 24 hours, and on hands for 12 hours.

The incubation period is usually two to four days from exposure to onset of clinical signs. The highest amounts of viral shedding occur during this time; therefore, dogs are most contagious during this 2-4 day incubation period when they are not exhibiting signs of illness. Virus shedding decreases dramatically during the first 4 days of illness but may continue up to 7 days in most dogs and up to 10 days in some dogs with H3N8 canine influenza. Intermittent H3N2 shedding for up to 26 days can occur; therefore, dogs infected with H3N2 should be isolated for at least 21 days

There are several symptoms of dog flu all owners need to be aware of. Dog flu can range from mild to severe and, unlike human influenza, is not seasonal. Dogs affected by the virus will have symptoms like coughing (both moist and dry), sneezing, nasal discharge, purulent nasal discharge, runny eyes, fever, lethargy, and difficulty in breathing, according to American Kennel Club.

Although most cases of dog flu are mild, severe cases do occur as well. In these cases, dogs develop pneumonia, difficulty in breathing, and a high fever. Fortunately, the mortality rate of dog flu is relatively low, with less than 10 percent of dog flu cases resulting in fatalities. Dog owners should still take their dogs to the vet, as secondary infections can develop from the virus

The dog flu vaccine is typically recommended according to how active your dog is, if the animal regularly spends time in kennels, or if you live in an area with a high incidence of dog flu.

If your dog has a high risk of contracting canine influenza, your veterinarian may recommend the H3N2 vaccine as a precaution.

According to the AVMA, the canine influenza vaccine is a ‘lifestyle’ vaccine and is not recommended for every dog. In general, the vaccine is intended for the protection of dogs at risk for exposure to the canine influenza virus, which includes those that either participate in activities with many other dogs.