Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

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Canine Influenza Frequently Asked Questions


Pet Column for the week of February 5, 2010

Related information:

Related site - Intervet Schering-Ploough Animal Health
Related site - American Veterinary Medical Association
Related site - UC Davis Koret Shelter Medicine Program
Related site - ASPCA

Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907

What is canine influenza?

  • A newly emerging infectious disease caused by a "flu" virus - H3N8, not H1N1.
  • First reported case in 2004 on a greyhound track in Florida. Virus started as equine influenza virus then mutated to cross from horses to dogs sharing the track.
  • The virus spreads the same way as the human flu: direct contact, airborne, contact with infected surfaces.


How can I protect my dog from canine influenza?
  • A new canine influenza vaccine developed by Intervet/Schering-Plough has proven to significantly reduce the severity and duration of clinical signs.
  • The initial vaccination requires 2 doses given 2-4 weeks apart followed by annual revaccination.
  • If your dog is being vaccinated for kennel cough (Bordetella), it is a candidate for the influenza vaccine.


Is the vaccine safe?
The new vaccine was proven safe and well tolerated in more than 700 dogs ranging from six weeks to 10 years old.

Is my dog at risk?
The following may increase the risk of your dog becoming exposed to H3N8:
  • Boarding at a kennel or going to doggie daycare
  • Attending a group training
  • Visiting a groomer, dog parks or engaging with other dogs on daily walks
  • Going to dog shows
  • Owned by a veterinarian or anyone working in the animal care industry with exposure to large numbers of dogs (can carry it home)


How contagious is canine influenza?
It is highly contagious. Virtually every dog exposed to the virus will become infected because the virus is new and dogs have no natural immunity to it. About 80 percent of infected dogs will show signs of disease, but dogs that are infected and do not show signs can still spread the virus to other dogs. Greyhounds appear to be especially susceptible to the virus and develop a hemorrhagic form.

What are the signs of canine influenza?
  • Persistent cough, similar to kennel cough
  • Eighty percent of infected dogs will have mild form with low grade fever, nasal discharge, lack of energy, loss of appetite and cough that can last for up to one month.


What happens if my dog becomes infected?
  • There is no specific treatment
  • Provide supportive care (good nutrition, fluid intake, shelter etc.)
  • Sometimes viral infection is complicated by secondary bacterial infections that may need to be treated with antibiotics.
  • Human "flu" medicines should NOT be given to dogs.


How serious is canine influenza?
  • Usually mild, but can become serious in some dogs.
  • About 20 percent of cases have more severe signs such as high fever and pneumonia.
  • Of the 20 percent, 8 percent have died from complications associated with the disease.


  • How is canine influenza diagnosed?
    • Difficult to diagnose because it is often confused with kennel cough until the illness becomes unusually severe or lasts an unusually long time.
    • Lab tests must be taken at appropriate time during illness to yield reliable results.
    • Two separate tests: nasal swabs or blood testing.


    How can I learn more about influenza?
    Your veterinarian is the best person to answer any questions you have.

    For more information or to schedule an appointment to administer the vaccine, you may contact Dr. Kandi Norrell, primary care veterinarian, at the University of Illinois Small Animal Clinic at 217-244-0475.