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Could You Recognize Dog Flu?
By Jennifer Viegas
“Flu” seems to be a catchall word used to describe many different
illnesses, from human flu to avian flu. Now, dogs can catch dog flu.
But do you really understand the symptoms, treatment and
prevention of this potentially life-threatening illness?

Recently, the Centers for Disease Control and Prevention issued new
guidelines about canine influenza (aka dog flu). Ruben Donis, chief of
the Molecular Virology and Vaccines Branch of the CDC’s Influenza
Division and other experts help answer key questions about this
disease.
How did canine influenza first emerge?

The canine influenza virus was first identified in 2004, but scientists believe it was around for a while
beforehand. “We have demonstrated that the virus was in the greyhound population as early as 1999,
and we speculate it was likely introduced sometime before that,” says Tara Anderson, a researcher at
the University of Florida College of Veterinary Medicine. She and others first became aware of it due to
numerous outbreaks of respiratory disease among dogs at racing tracks.

Donis explains that the virus causing the flu, called H3N8, was known to exist in horses for more than
40 years. “Scientists believe that the virus jumped species, from horses to dogs, and has now adapted
to cause illness in dogs and spread efficiently among dogs.”

Can it spread to humans?
There are no known cases of humans suffering from H3N8. “This is a disease of dogs, not of humans,”
says Donis.

What are the symptoms?

Affected dogs may show the following symptoms: cough, runny nose, fever, pneumonia (but, as with
humans, only a small percentage of dogs get pneumonia).
How does the illness spread from dog to dog?
Airborne transmission is the primary way canine influenza spreads, according to Annette Uda, founder
of PetAirapy LLC, an Illinois-based company that specializes in air-purifying systems for the pet industry.
“When an infected dog coughs or sneezes, it releases the virus into the air. The virus, which is in the
form of droplet nuclei, is able to survive for hours -- and in some cases much longer -- on dust and
dander until it is inhaled by another animal, causing infection.”

Can any dog get the disease?
“Nearly all dogs are susceptible to infection,” says Donis. About 80 percent will just get a mild form of
the disease. A lower percentage can get pneumonia and suffer more severe cases. Among that
group, the fatality rate is between 5 and 8 percent.

How is canine influenza treated?
It is important to first confirm the presence of H3N8 via tests -- either on blood or respiratory
secretions or both. Once the disease is confirmed, treatment largely consists of supportive care, such
as taking steps to ensure your pet is well-hydrated. “Broad-spectrum antibiotics may be prescribed by
your veterinarian if a secondary bacterial infection is suspected,” says Donis.

How can you help prevent your dog from catching canine influenza?
Try to keep your dog away from other dogs that might be ill. Dogs in close quarters, such shelters and
racing facilities, are more susceptible to this disease. “It’s very much a proximity issue,” says Ron
Schultz, chair of the Department of Pathobiological Sciences at the University of Wisconsin-Madison
School of Veterinary Medicine. “Open-air spaces like dog parks, however, carry a much lower risk.”

Schultz helped formulate a vaccine for dog flu, which is now widely available. He recommends it for
dogs that are at high risk of infection, such as dogs that regularly go to doggy day care facilities or
participate in dog shows. “Even if you have 20-30 percent of dogs vaccinated, that would make a
difference. It’s a group thing,” explains Schultz. “It only takes one of those dog flu outbreaks, and
then people really start to think. It’s not ‘mild’ for the dog that dies.”

What should you do if your dog has a cough?
Coughing in dogs is frequently associated with a contagious illness, just as it is in humans. Take your
pet immediately to the vet for a checkup. This is for the sake of your furry pal, and also for that of
other dogs that might catch the illness. Older canines and those with weakened immune systems are
likely more susceptible to severe forms of the virus.

If your dog is diagnosed with canine influenza, keep it away from other animals. “Clothing, equipment,
surfaces and hands should be cleaned and disinfected after exposure to dogs showing signs of
respiratory disease,” advises Donis.

Jennifer Viegas is the managing editor of The Dog Daily. She is a journalist for Discovery News, the
news service for the Discovery Channel, and has written more than 20 books on animals, health and
other science-related topics.