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Canine Influenza

Consider vaccinating your dog! Cases of Canine Influenza have been reported in Kentucky and Ohio.


  • Canine influenza (CI) is a highly contagious respiratory infection that was first recognized in 2005.
  • An investigation showed that this respiratory illness was caused by the equine influenza A H3N8 virus. Scientists believe that this virus jumped species, from horses to dogs.
  • Most common among dogs that have frequent contact with other dogs at dog parks, kennels and shelters.
  • This is a disease of dogs, not of humans.


  • Direct contact with aerosolized (sneezing and coughing) respiratory secretions from infected dogs
  • Coming into contact with contaminated objects
  • Moving contaminated objects or materials between infected and uninfected dogs.
  • Therefore, dog owners whose dogs are coughing or showing other signs of respiratory disease should not expose other dogs to the virus.

Clinical signs

  • Mild form
    • Some dogs have asymptomatic infections (no signs)
    • Moist cough that persists for 10 to 30 days.
    • Lethargic
    • Reduced appetite
    • Fever
    • Sneezing and discharge from the eyes
    • Dry cough similar to the traditional “canine cough”
    • Thick nasal discharge may be seen, which is usually caused by a secondary bacterial infection.
  • Severe form
    • High fevers (104ºF to 106ºF)
    • Clinical signs of pneumonia, such as increased respiratory rates and effort. Pneumonia may be due to a secondary bacterial infection.
    • This form is more common in dogs that are immunocompromised such as puppies and seniors.

Although this is a relatively new cause of disease in dogs and nearly all dogs are susceptible to infection, about 80 percent of infected dogs will have a mild form of disease.


  • Testing to confirm canine influenza virus infection is available. Your veterinarian can tell you if testing is appropriate. The tests can be performed using respiratory secretions collected at the time of disease onset or using two blood samples; the first collected while the animal is sick and the second 2 to 3 weeks later.


  • Treatment largely consists of supportive care. This helps the dog mount an immune response. In the milder form of the disease, this care may include medication to make your dog more comfortable and fluids to ensure that your dog remains well-hydrated. Broad spectrum antibiotics may be prescribed by your veterinarian if a secondary bacterial infection is suspected.
  • Fatal cases of pneumonia resulting from infection with canine influenza virus have been reported in dogs, but the fatality rate is low (less than 10%). Most dogs with CI recover in 2-3 weeks


  • Vaccination. This is a series of two booster vaccines 3-4 weeks apart, then yearly. This protocol is the same whether it is a puppy or adult that has never been vaccinated. The puppy’s vaccine should be given between the ages of 6 weeks and 16 weeks.
  • This is a lifestyle vaccine. If your dog never boards, attends daycare, or goes to dog parks then the likelihood of being exposed to this virus is extremely low and may not be necessary.