Laurie Anne Walden, DVM
You may have read about canine influenza in the news recently. Cases of canine flu have been confirmed in North Carolina, and 2 dogs have died. Here's what you need to know.
How canine flu spreads
Canine flu is caused by an influenza A virus that is highly contagious among dogs. It spreads through respiratory tract secretions. Sources of infection typically include the following:
Two strains of canine influenza virus have been identified in the United States. H3N8 virus was first seen in this country in 2004. H3N2 virus caused an outbreak in the Chicago area in 2015 and the recent cases in Florida and Georgia.
About 80% of dogs exposed to the virus develop clinical signs of infection. About 20% have no symptoms but can still spread the virus to other dogs.
Infected dogs are most contagious during the first 2 to 3 days after infection, before they show signs of illness. Dogs infected with H3N2 virus can continue shedding virus, potentially infecting other dogs, for more than 3 weeks.
Cats can also contract canine flu and spread it to dogs. To date there has been no evidence of the virus infecting humans.
Signs of canine flu
Clinical signs typically appear 2 to 3 days after exposure to the virus. Most signs are similar to those caused by canine infectious tracheobronchitis (kennel cough) and other respiratory infections. The mortality rate is less than 10%.
Most dogs develop mild symptoms:
Some dogs develop more severe illness:
Diagnosis and treatment
Canine flu is diagnosed by sending swabs or blood samples to a diagnostic laboratory. There is no rapid in-house test for canine influenza virus. However, treatment does not depend on having a definite diagnosis.
As with human influenza, treatment is supportive and depends on the patient's symptoms. Antibiotics do not affect the virus that causes flu. Most dogs have mild illness that resolves after 2 to 3 weeks. Some dogs need treatment for secondary bacterial infections, dehydration, and other problems caused by the virus.
As of June 2017, Mallard Creek Animal Hospital uses a new canine influenza vaccine that covers both strains of the virus.
What you should do
For more information: