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Could This Be a Bad “Flu” Season for Dogs, Too?

While the SDSU ADRDL has not yet detected canine influenza in submissions yet this year, the virus has gotten a lot of attention elsewhere around the country.  In recent weeks, canine influenza infections have surged in places such as the south San Francisco Bay area. 

Since its first detection in Chicago in 2015, the novel H3N2 virus has been detected in many areas throughout the US, including several cases that year in the Black Hills.  The strain is distinct from the previously-known H3N8 strain of canine influenza, and is closely related to strains known to infect dogs in certain parts of Asia.  To date, this strain has not been observed to infect people or other species since it began infecting dogs in the US.   It’s a rapidly spreading virus that has garnered attention from pet owners and veterinarians, who may be interested in how the virus is detected in their canine patients. 

Signs of influenza infection in affected dogs include coughing, nasal discharge, lethargy, and fever. Signs of infection resolve gradually over 2-4 weeks with good supportive care.  In a few severe cases, the initial influenza infection can be complicated by a bacterial infection, resulting in pneumonia. Oftentimes, however, the infection is mild and may not even be noticed by the owner.

The SDSU ADRDL can test samples from dogs for influenza.  It’s especially important to understand that timing of sample collection is critical.  The canine influenza virus is only shed 2-4 days after initial clinical signs, so if the duration of illness has been longer than that, virus is not likely to be present in samples taken later in the course of disease, even in dogs showing clinical signs.

Testing considerations:

  1. Use a polyester, Dacron, or rayon swab with a plastic shaft (BD BLL sterile culture swabs are OK).
  2. Collect both nasal and deep pharyngeal swabs.  
    • Nasal swabs: insert swab into nares.
    • Pharyngeal swabs: swab the back of the throat, near the end of the soft palate.
  3. Place swab back into tube and add several drops of saline to keep the tube moist.
  4. If you have parafilm, cover the tube with it to seal it.
  5. Keep the samples refrigerated until they can be mailed (preferably the day of sampling).
  6. Mail with ice packs and mail overnight.

Testing is performed daily at a cost of $40/sample.  The test is a real-time PCR procedure that detects Influenza A.  If subtyping to characterize the virus as the canine H3N2 strain is desired, we can forward the sample on for further testing. 

To submit, go to SDSU Animal Disease Research and Diagnostic Laboratory; click on “submission and other forms” on the left side of the page to find the “all species health form.” Write in “canine influenza testing” and include the form with the sample.

An update of canine influenza “tracking” throughout the US is located at: Cornell University H3N2 Canine Influenza Information

Information on canine influenza for veterinarians from the AVMA can be found at: Canine Influenza FAQs

Information regarding the zoonotic potential of canine influenza from the CDC can be found at: Key Facts about Canine Influenza