Canine Influenza

Sick dog picture

Elizabeth Rogers, DVM

Within the past month, our local news and radio station reported a new potential outbreak of H3N2 in Austin. Our office has received a few calls regarding this report. I have called the state and local veterinary diagnostic labs and currently they have only diagnosed H3N2 in Austin and some in Houston. No cases are reported here in DFW at this point.  I just wanted to give you information so that you are aware of canine influenza and your options. Please call our office if you have any further questions or concerns.

What is it?

Canine influenza is a highly contagious respiratory infection of dogs caused by the influenza A virus.  In 2004, the first strain was reported to be the H3N8 and was found at dog tracks with racing greyhounds.  There was another outbreak of canine influenza with a new strain H3N2 in May 2015 in Chicago, Illinois with a few cases in Austin and Houston.  Last week, there was a news report on local news and radio about a possible outbreak of canine influenza with the same strain as Chicago down in Austin and Houston.

Signs of Canine Flu (can look similar to Kennel Cough)

  • Persistent cough
  • Thick nasal discharge
  • Fever (often 104-105F)
  • Lethargy
  • Eye Discharge
  • Reduced appetite
  • Most dogs have a mild form of the infection, but some dogs may develop pneumonia and have a more serious course that requires hospitalization.


** Some dogs may show no signs or illness but can shed the virus and infect other dogs.

Risk Factors

  • Increased risk for dogs exposed to other dogs such as:
    • Boarding
    • Doggie Day Care
    • Dog Parks
    • Grooming Salons
    • Dog Sporting Events
    • Animal Shelters
    • Dog Shows
    • Puppy Classes
    • Dog Social Events
  • Almost all dogs regardless of breed or age- extra precautions in puppies, pregnant dogs and elderly dogs


  • Dogs are most contagious during the 2-4 day post infection when virus is shed from nasal secretions.
  • Canine influenza can be spread from dog to dog through the following ways:
    • Air borne virus particles (e.g., through coughing or sneezing)
    • Physical contact with other dogs (e.g., touching noses)
    • Indirect contact from objects (e.g., if a dog touches or plays with toys and food bowls that were touched by infected dogs )
    • Humans can even move the virus between dogs (e.g., owners may spread the virus if they pet an infected dog, or even touch a toy or doorknob that a dog has contacted, and then touch another dog before washing their hands)
  • Infected dogs may not show signs of illness
  • Mortality rate (death) is low (10%<)


  • Can be diagnosed early phase of the illness (less than 3 days) by testing nasal or pharyngeal (throat) swabs.
  • Most accurate test is a blood test with 2 samples – the first collected during the first week of illness and the second collected 10-14 days later.



  • No medication is available to treat canine influenza directly. The illness must simply run its course.
  • Currently we treat canine influenza patients with supportive care and making sure the dog is as comfortable as possible, hydrated, and eating well which help boost the dog’s immune system so it can fight the virus on its own.
  • Dogs that have nasal discharge or pneumonia signs are usually given an antibiotic because they are likely to have a secondary bacterial infection.
  • Some dogs with more severe illness may require hospitalization for intravenous fluids, oxygen, nebulization, and antibiotics.
  • Seek veterinary care at the first signs of a respiratory infection in your dog because early treatment can result in better outcomes.



  • Minimize the spread of canine influenza
    • Keep your dog at home if he or she has signs of a respiratory infection, and contact your veterinarian regarding appropriate care and evaluation.
    • Routinely wash your dog’s food and water bowls and toys with soap and water.
    • Sanitize your hands with soap and water or an alcohol-based hand sanitizer, and wash your clothes after coming in contact with a dog that has signs of a respiratory infection.
    • Make sure the professionals you know who provide care for your dog(s) are knowledgeable about canine influenza and are taking appropriate precautions to minimize its spread.
    • Canine influenza does not usually survive in the environment beyond 48 hours and are inactivated or killed by disinfectants.


  • There are 2 vaccines available for both strains- H3N2 and H8N2 are available. Vaccines are proven:
    • To significantly reduce the clinical signs, severity, and spread of canine influenza infection
    • Reduced the incidence and severity of coughing
    • Decreased the overall clinical signs of disease, including ocular and nasal discharge, coughing, sneezing, depression, and dyspnea
    • Reduced the days and amount of viral shedding
    • Demonstrated protection against the formation and severity of lung lesions
    • Contains killed virus combined with an adjuvant to enhance the immune response
  • We have both strains of canine influenza vaccines in our hospital. Vaccination protocol recommended is a vaccination of each strain and then boost each vaccine in 2-4 weeks. The H3N2 is $27.00 /vaccine and the H8N2 is $25.76 /vaccine.