There are two strains of flu virus: H3N8 was first detected/confirmed in racing greyhounds in the US in 2004. H3N2 was confirmed in the US in 2015; this one affected primarily dog shows at first. Dog flu has been confirmed in 46 states so far.

  • H3N2 can also affect cats, but there is no vaccine for cats.
  • Both upper and lower respiratory systems can be involved and clinical signs can include:
  • Can mimic kennel cough
  • Lethargy and depression
  • Frequent cough (can persist up to 3 weeks), sneezing, discharge from the eyes and nose
  • Decreased appetite
  • Increased or labored breathing
  • Fever
  • Can progress to life-threatening pneumonia
  • Concurrent bacterial infections

What to do if you think your dog is showing clinical signs:

See your veterinarian as soon as possible. Once you arrive at the clinic, wait in the car and call us to let us know that you are here. We will then take you right into an exam room as soon as we have one available. Please do not linger outside or in the reception area or touch anything in the clinic, including doors. If at all possible, carry your dog and do not let them walk around. Do not let your dog get close to or touch other dogs.


This is a highly contagious disease but death is rare. About 20% of dogs can progress to pneumonia. The incubation period is around 5 days, but a lot of dogs can show clinical signs in 2-3 days.

Direct contact, aerosol transmission (a cough and sneeze can carry long distance on air)

Indirect contact contaminated environment (leashes, tables, floors, doors, bowls, etc) and people (hands and clothing).

Any dog can get this. Dogs at higher risk are dogs that participate in group activities with other dogs and housed with other dogs such as at shelters, etc. Dog shows, boarding, dog parks, grooming, training classes, vet clinics, animal shelters, rescue groups, etc. Even just walking your dog around other dogs. If your dog is showing clinical signs, please do not let your dog be around other dogs for 4 weeks.

There is a test for this involving nasal and pharyngeal swabs.

Treatment is supportive and outpatient unless severe, in which your dog will be hospitalized.

The flu vaccine that we have now is called a “Bivalent” vaccine. It protects against both H3N2 and H3N8. Like all vaccines, it is not 100% and owners still need to take precautions. If a vaccinated dog comes down with the flu, the symptoms are usually not as severe and are of shorter duration.

If your dog was vaccinated with the H3N8 vaccine only, then he will need to be given the new vaccine. He will get the first vaccination, boostered 2-3 weeks later, and then will receive it annually.

Should all dogs be vaccinated?

This is to be discussed with your Doctor. All dogs are at risk for contracting this disease. We, and most other boarding facilities, are requiring vaccination with the bivalent vaccine for boarding pets.

When is your pet protected?

Maximum protection should occur no earlier than 3 weeks after the second injection. We appreciate your patience in waiting with us for this product. If you have any questions regarding this vaccine, please feel free to email us at or call us directly at 281.997.1426.