Last week we talked about vaccinating against three of the respiratory pathogens — canine adenovirus type 2 (CAV-2), parainfluenza virus (Pi), and Bordetella bronchiseptica (Bb) — that together or alone are responsible for many cases of kennel cough in dogs. I mentioned that I consider all of these vaccines to be situational and that deciding whether or not to give them is based primarily on the amount of contact a dog has with environments (particularly indoor environments) frequented by other dogs.

In some ways, today’s topic — the canine influenza vaccine — presents similar choices. The symptoms of canine influenza are indistinguishable from traditional kennel cough. Typically, dogs will cough, sneeze, have a runny nose, lose their appetite, and be somewhat lethargic but get better with symptomatic care only. A small percentage of dogs do go on to develop pneumonia, however, which proves fatal in less than 10 percent of cases. An especially severe type of pneumonia usually associated with a bacterial co-infection has been reported in greyhounds.

Canine influenza is a relatively new disease. It was first diagnosed in 2004 in a group of racing greyhounds in Florida. Testing has shown that the virus mutated from a strain of equine influenza and gained the ability to spread from dog to dog. Since then, canine influenza has moved across the country, now being found in 30 states and the District of Columbia.

Since the disease is so new, there are still significant portions of the country where it is has not yet gained a foothold. The first question that needs to be answered when determining if a dog needs an influenza vaccine is to find out whether the disease is endemic in the region in which you live or are planning travel to. Colorado, New York, Florida, and Pennsylvania are notorious canine flu hot spots, but ask a local veterinarian whether he or she has diagnosed cases in your area.

Next come the lifestyle determinations. Canine flu spreads best in enclosed spaces that contain a lot of animals (just like CAV-2, Pi, and Bb). If your dog goes to a boarding facility, doggy day care, groomer's shop, or shows, he has a higher than average chance of getting sick. In fact, some of these businesses and organizations are starting to require that dogs be vaccinated against canine flu. Dogs can also catch the flu directly from horses, so equine contact can be considered a risk factor.

Finally, take note of your dog’s health status. Does he have an immunosuppressive, cardiac, or respiratory disease that puts him at higher risk for flu complications? Flu vaccines do not eliminate the chances that a dog will be infected with the virus, but they do a reasonable job of reducing the severity of symptoms and the likelihood that serious complications might develop.

When a dog first receives the canine influenza vaccine, two inoculations given 2-4 weeks apart are required. From this point on, annual boosters are recommended unless a dog’s risk factors decrease, Veterinarians have not noted any type of seasonality associated with canine influenza virus infections, so there is no need to worry about when during the year to give the vaccine.

Dr. Jennifer Coates

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