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Canine influenza virus: Is your dog at risk?

By: Justine A. Lee, DVM, DACVECC, DABT
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In March of 2015, a devastating outbreak of Canine Influenza Virus (CIV) affected the Chicago, Illinois area. Since then, almost 100 dogs have been confirmed to have CIV, based on laboratory tests done at Cornell. There are reports of over a 1000 dogs being affected and several deaths reported since that time.

What is Canine Influenza Virus (CIV)?
CIV, a highly contagious virus, was discovered in 2004 in Florida at a Greyhound racing track. It is believed that an equine (horse) influenza virus mutated, and became capable of infecting dogs. Since then, the virus has popped up in Virginia, New York and Colorado, spreading to over 40 states and counting.

There are many different types of influenza virus, and this specific virus appears to affect only dogs. It does not appear to be contagious to humans. Dogs can spread the virus before they show symptoms, making risk for exposure even higher.  In as little as 5 days of exposure to CIV, dogs can develop clinical signs of upper or lower respiratory problems. While most dogs may only develop mild to moderate signs, it’s estimated that up to 20 percent can develop severe signs. Even with treatment, CIVcan be fatal to dogs.

Clinical signs of CIV can range from mild signs of coughing, sneezing or nasal discharge to more severe, life-threatening signs such as:

  • Lethargy/weakness
  • Malaise
  • Not eating (progressing to complete anorexia)
  • Coughing
  • Expectorating (e.g., retching)
  • Constant panting
  • Increased respiratory effort
  • Open mouth breathing 
  • Exercise intolerance
  • Increased abdominal effort to breath
  • Fever
  • Blue-tinged gums
  • Difficulty breathing
  • Collapse


Is your dog at risk?
Dogs that have exposure to other dogs are at high-risk. In other words, if your dog goes to a doggy daycare, dog park, boarding facility, dog shows, grooming facility, etc., your dog may be more at risk.  Dogs that travel with their parents, go into the office, or even run errands may be at higher risk.  With this recent Chicago outbreak, many doggy daycares and city parks have temporarily shut down to prevent further spread. To prevent exposure to CIV, avoid these areas in affected areas until the outbreak is over.

The good news? There’s a vaccine for Canine Influenza Virus (Nobivac® Canine Flu H3N8, Merck Animal Health). So for those who have high-risk dogs or living in Chicago right now, this option may be worth discussing with your veterinarian. Dogs have no natural immunity to CIV, so the vaccine is key in limiting risk.

That said, this isn’t typically a “core” vaccine (one we give to all dogs); however, when given to  at-risk dogs (e.g., those living in or traveling to Chicago!), the vaccine has been shown to significantly decrease the severity of CIV infection, reduce the damage to the lungs, and minimize viral shedding (how the virus is spread) . Keep in mind that this vaccine is not the same thing as the “Kennel Cough” vaccine (which is for a bacteria called Bordatella bronchiseptica), even though some symptoms are similar. Just like other vaccines, the CIV vaccine needs a booster 2-4 weeks after the first dose (Remember, just one dose is not effective alone, as the body needs to respond to the second vaccine to stimulate the immune system). 

If you think your dog was exposed, talk to your veterinarian and make sure your dog checks out okay at the veterinarian with a thorough physical exam. Also, make sure to clean the environment, dog bowls, leashes, dog beds, etc. to be safe.  Remember, human clothes can be contaminated as well.  Thankfully, traditional disinfectants (like a 10% diluted bleach solution) can kill Canine Influenza Virus easily with appropriate hygiene, isolation, and sanitation procedures.

When in doubt, if your dog is showing any signs at all, get to a veterinarian immediately - even if means going to the emergency clinic in the middle of the night. The sooner you notice any problems, the sooner treatment can be started.

Once you get to a veterinarian, certain tests may need to be done, including blood work (to look at the white blood cell count, kidney and liver function, etc.), a test for CIV (which includes sending swabs from the nose and pharynx (throat) directly to Cornell University’s Veterinary Diagnostic Laboratory), and chest x-rays to see if the CIV has resulted in pneumonia or not. 

Treatment for CIV may range from outpatient therapy to being hospitalized in the intensive care unit. If your dog is only mildly affected with CIV, treatment may oral antibiotics (to limit risk for pneumonia), limited exercise, isolation from other dogs (for at least 2 weeks), and an anti-cough medication (these should only be given if x-rays have been done and are normal). 

If your dog is more severely affected, treatment will require hospitalization and isolation from other patients in the hospital. Treatment may also include:

  • Intravenous fluids
  • Oxygen therapy
  • IV antibiotics 
  • Nebulization and coupage to break up the infection in the lungs
  • Nutritional support 
  • Supportive care and oxygen level monitoring
  • Anti-vomiting medication
  • Possible sedatives
  • Isolation from other dogs for at least 2 weeks


Again, to be safe, pet owners should avoid affected, high-risk areas until the outbreak ceases. When in doubt, talk to your veterinarian about how to protect your dog and whether there are reports of CIV in your area. While this is a less common virus that dogs get, we want to make sure to keep our four-legged canine family members safe!



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