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The Daily Vet by PetMD

The Daily Vet is a blog featuring veterinarians from all walks of life. Every week they will tackle entertaining, interesting, and sometimes difficult topics in the world of animal medicine – all in the hopes that their unique insights and personal experiences will help you to understand your pets.

Cases of Dog Flu Reported to Be on the Rise, and All Dogs Are at Risk

2 min read

It’s flu time; for us and, increasingly, for our dogs. While the Zika virus is all over the news—and rightfully so, as it has terrifying consequences for pregnant women in mosquito endemic areas—canine influenza is also on the rise.


So how worried should you be, exactly? Like all complicated, messy things in life, the answer is a definitive and concise: it depends.


Let’s sort out a few components of the disease and what health officers are monitoring.


How sick does it make dogs?


The vast majority of affected dogs experience mild respiratory symptoms: a cough lasting 10-21 days, nasal discharge, and mild fever. More severely affected dogs can develop signs of pneumonia.


How contagious is it?


Canine influenza is very contagious. Virtually all dogs exposed to the virus become infected and 80% develop clinical signs of illness. The other 20%, while asymptomatic, may still spread the virus to other dogs. Unlike human influenza, canine influenza doesn’t have a clear “season” and can occur year-round.


Should my dog get the flu vaccine?


The current canine influenza vaccine protects against the H3N8 strain, which has been present in the United States since 2004. A different strain of canine influenza, H3N2, is responsible for many of the outbreaks in the news and was first diagnosed in the United States in March 2015. It is unknown if the H3N8 vaccine protects against the H3N2 strain.


In November of 2015, the USDA granted conditional licenses to two pharmaceutical companies to market a vaccine for H3N2. In both cases, the vaccine is intended not to prevent infection, but to reduce the severity of the symptoms and the spread of the disease. Whether or not you get the vaccine is a decision you should make in partnership with your veterinarian, taking into consideration the risk of your dogs being exposed.


How is dog influenza diagnosed?


Canine influenza cannot be diagnosed based on clinical signs alone as it mimics so many other respiratory illnesses. Veterinarians can diagnose canine influenza through a variety of tests, including blood tests and nasal swabs.


How is dog flu treated?


There is no one definitive treatment for influenza. Treatment is limited to supportive care: fluids when indicated, anti-inflammatory medications for fever, and antibiotics for secondary bacterial infections.


Can people or non-canine pets get the dog flu?


Currently, this virus is not shown to spread to other species.


The concern for any influenza virus is the rapid evolution of viral strains. While the flu is not contagious to people now, that doesn’t mean it will not be in the future. H3N8 itself originated as an equine virus that adapted into a canine specific influenza; a scary but, thankfully, rare event. This, more than anything else, is why the CDC is so interested in this illness.



Dr. Jessica Vogelsang