As canine influenza continues it’s rather gradual, patchwork movement across North America, an outbreak at a greyhound racetrack southeast of Houston highlights some of the concerns about this virus. Canine influenza has been active in the Houston region for some time, causing sporadic infections as well as outbreaks in pet dogs in the community and in veterinary clinics.

Greyhound tracks are a great place for influenza transmission because they have a lot of dogs in close quarters, and racetrack outbreaks can be large and severe. In this outbreak, approximately 100 dogs have been affected so far, with six deaths. It sounds like there are 600-700 dogs on the track, and given how transmissible the virus is, unless they have very tight infection control practices in place to separate groups of dogs (unlikely), it’s reasonable to assume that many more dogs will be infected, or have already been infected but weren’t recognized because they had mild disease. The ~6% mortality rate is not surprising, as dogs can die from severe influenza or because of bacterial pneumonia that develops afterwards. Higher death rates are talked about, and were features of the early reports of canine flu in Florida, but this lower rate seems to be more typical.

Local Humane Society personnel are rightly warning pet owners to be on the lookout for canine flu. Public awareness is critical, although I’d argue with some of their advice:

"The only protection is the dog flu vaccine."

  • Not really. It’s part of the infection prevention plan but not the only thing. Vaccination is an effective way to reduce the incidence or severity of disease, but it’s not 100%. Vaccination should be considered the last line of defense that comes into play when efforts to avoid the virus have failed. If the dog doesn’t get exposed to canine flu, it won’t get influenza, regardless of vaccination status. Dog owners need to be aware of high-risk situations and avoid contact with dogs that are or have recently been sick. That being said, in an area where canine flu is active, vaccination is a good idea, since you can never completely guarantee your dog won’t be exposed to the virus if it’s exposed to other dogs.

"Dog owners were warned if they noticed any flu-like symptoms in their dog to take them to a vet immediately for antibiotics and the vaccine and not to take their dog to the park or doggie daycare."

  • I agree with the last part. If your dog is sick, keep it away from areas where other dogs mingle while it’s sick and for about 10 days after it gets better. So, if that’s the case, why take all potentially sick animals into the vet right away? It might just result in exposure of other dogs to the virus. If you have influenza and you’re not very sick or at high risk for complications, the recommendation isn’t to immediately go to the doctor. It’s to rest and stay away from other people. The same applies for dogs.
  • Calling a veterinarian to see whether the dog should be examined makes sense. This also helps ensure that if the dog does go to the clinic, it can be handled properly. By that, I mean instead of showing up, checking in at the front desk and lingering in the waiting room with other dogs for a while, a dog with suspected flu should be admitted directly into isolation or an exam room. This can be done by calling the front desk on arrival or by checking in without the dog, so that the dog can be taken directly to a contained area to avoid other dogs.
  • Antibiotics are rarely needed. Antibiotics don’t kill influenza virus, so they are indicated only if there is evidence (or very high risk) of secondary bacterial disease, which doesn’t happen in most cases. We don’t want every coughing dog on antibiotics, since few need them.