Canine Flu

What is canine influenza (dog flu)?

Canine influenza (also known as dog flu) is a contagious respiratory disease in dogs caused by specific Type A influenza viruses known to infect dogs. These are called "canine influenza viruses." Dog flu is a disease of dogs only. No human infections with canine influenza have ever been reported. It has been reported sporadically in some areas in the US.

In the Southeast, canine influenza has been sporadically reported, but since it is highly contagious, if there were outbreaks, more dogs would be sick from this disease. This has not been the case, yet. So we consider it to be a very minor concern.

There are two different influenza A dog flu viruses: one is an H3N8 virus and the other is an H3N2 virus.

In 2004, some greyhounds at a racetrack in Florida that had respiratory disease with fever were diagnosed with influenza H3N8, a horse virus known for more than 40 years. The virus may have changed in some way to adapt to dogs.

In 2015, an influenza virus, H3N2, was identified from some dogs with respiratory disease and fever in Chicago. It was determined that this is an Avian (bird) strain of flu virus traced back to its origin in Korea. It's identification in the US has been reported, but rarely. Canine influenza appears in pockets where an infected dog spreads the virus to those dogs in close proximity. Recent outbreaks of canine influenza have been limited dogs that have been to a dog show.

What are signs of canine influenza infection in dogs?
The signs of this illness in dogs are cough, runny nose, and fever, but not all dogs will show signs of illness. The severity of illness associated with canine flu in dogs can range from no signs to severe illness resulting in pneumonia and sometimes death

How serious is canine influenza infection in dogs?
The percentage of dogs infected with this disease is small and the percentage of dogs that die is very small. Some dogs have asymptomatic infections (no signs of illness), while some have severe infections. Severe illness is characterized by the onset of pneumonia, which is what causes death in some affected dogs. This is a relatively new cause of disease in dogs and nearly all dogs are susceptible to infection.

How is canine influenza spread?

Almost all dogs are susceptible to canine flu infection, and illness tends to spread among dogs housed in kennels and shelters. Canine flu can spread to other dogs by direct contact with aerosolized respiratory secretions (coughing and sneezing) from infected dogs. Surfaces of walls, bowls, and toys can be infected with the influenza virus, so disinfection of these objects is important.

Dog owners whose dogs are coughing or showing other signs of respiratory disease should not expose their dog to other dogs.

Is there a test for canine influenza?

Testing to confirm canine influenza virus infection in dogs is available. When we suspect a case, we can send off bloodwork to test for canine influenza. It is a test that can take several weeks for us to get the results.

How is canine influenza infection in dogs treated?

Treatment largely consists of supportive care. This helps the dog mount an immune response. In the milder form of the disease, this care may include medication to make your dog more comfortable and fluids to ensure that your dog remains well-hydrated. Broad spectrum antibiotics may be prescribed if a secondary bacterial infection is suspected.

Is there a vaccine against canine influenza?

There is a canine vaccine against H3N8 and H3N2. It was initially made for the racing greyhound population, but it is now available for all dogs. It is administered in 2 doses 4 weeks apart. The vaccine does not prevent disease, but it lessens the severity of the symptoms in exposed dogs.

Due to the small numbers of confirmed cases reported in the Southeast US and the mild nature of the disease, we do not currently recommend influenza vaccinations for all dogs. Dogs going to dog shows should be vaccinated.