With a recent canine influenza outbreak in the Palm Beach area, Groves Veterinary Clinic wants you to know how to keep your dogs safe. To effectively minimize your dog’s risk for this highly contagious threat, you need to understand canine influenza, its transmission, and how to protect your dog during this central Florida outbreak and beyond.

Question: What is canine influenza?

Answer: Flu viruses are not only highly contagious, but also highly adaptive. They frequently form new strains and cross into different species. Canine influenza (CIV)—a poster child for such evolution— can be divided into two strains:

  • H3N8 — First found in racing greyhounds here in Florida in 2004, H3N8 is a genetic variant of an equine influenza virus that hopped species to canines. H3N8 has been confirmed in all 50 states.
  • H3N2 — The most recent strain, H3N2, appeared in a 2015 outbreak in Chicago, but originated in Asia. H3N2 is believed to be a direct transfer from its original form, the avian flu, to dogs. By 2017, 25 states had confirmed H3N2’s presence. 

Because influenza viruses are unpredictable, they may become more or less infectious. Many veterinary reference labs and universities monitor CIV case numbers to track the virus’s mobility and morphology. This Cornell University surveillance map illustrates CIV prevalence across the country, and shows that Florida is an obvious hot bed. 

Q: How is canine influenza transmitted?

A: Canine influenza moves quickly from dog to dog, transmitted through direct and indirect contact, which makes the virus incredibly efficient and elusive. 

  • Direct transmission — Infected dogs can spread the virus through aerosolized droplets when they bark, cough, or sneeze, or have close physical contact with infected dogs. 
  • Indirect transmission — CIV can be carried on contaminated objects, such as shoes, clothing, leashes, and food and water bowls, and can also be transmitted via unwashed hands.  

The virus can survive for some time on various surfaces, making sanitation and disinfection key to virus prevention. Canine influenza can live for 48 hours on inanimate objects, 24 hours on clothing, and survive for 12 hours on unwashed hands. Fortunately, no proof exists that humans can contract CIV from dogs.

Q: Where could my dog be exposed to canine influenza?

A: Most CIV outbreaks occur in areas with large groups of dogs, such as:

  • Dog parks
  • Dog day care facilities
  • Boarding and grooming facilities
  • Animal shelters
  • Veterinary hospitals
  • Pet stores and training classes

Organized pet events, such as dog shows, pet parades, walks, and festivals, are also potential sources. Many boarding and grooming facilities now require proof of vaccination against canine influenza, but for peace of mind, always confirm health requirements, and avoid allowing your dog to visit locations that do not require CIV vaccination.

Q: What does canine influenza look like?

A: CIV signs typically appear only two to eight days after exposure, and often include:

  • A harsh, dry cough that may or may not be productive
  • Lethargy
  • Loss of appetite
  • Discharge from the eyes or nose, which may contain mucus
  • Fever 
  • High fever, pneumonia, and secondary bacterial infections requiring intense hospitalization, in severe cases

Testing by nasal swab or blood sample can confirm a CIV diagnosis, although confirmation may not significantly change treatment. Like the human flu, CIV does not have a cure or specific treatment, but is managed with supportive care as the body fights off the virus. Severe cases require hospitalization, while mild cases may be managed at home, with veterinary guidance. Canine influenza has a relatively low 10 percent fatality rate, with most deaths occurring in extremely severe cases, but the rate is high enough to serve as a warning to ensure your dog is vaccinated. 

Q: How can I protect my dog from canine influenza?

A: The only way to ensure your dog’s safety against CIV is vaccination. CIV vaccines contain inactivated strains of the H3N2 and H3N8 viruses, and cause a controlled exposure, so the pet’s immune system can recognize the virus in a natural exposure and mount a strong response. Similar to the human flu vaccine, your dog may still contract CIV, but the clinical signs and illness will be significantly minimized. The vaccine must be boostered between two and four weeks to provide full protection—you can schedule that appointment when your pet receives their first vaccine.  

Environmental precautions will also minimize your dog’s CIV risk. Ensure your boarding facility, day care, and groomer require CIV vaccination, and that they sanitize regularly. Do not let your dog share water bowls, toys, or care supplies such as brushes and leashes, with unfamiliar dogs. An infected dog can shed the CIV virus for up to 20 days after initial exposure, so exercise great caution during an outbreak. 

For additional questions about canine influenza, if you are concerned your dog is showing illness signs, or to schedule their CIV vaccination, contact Groves Veterinary Clinic.