Canine Influenza Virus

Canine Influenza Virus

Recently, Schering-Plough received conditional licensing approval of their canine influenza vaccine. This development has resulted in many inquiries from clients regarding the need for and benefit of this vaccine. This vaccine is currently conditionally licensed to “reduce the incidence and severity of lung lesions as well as the duration of coughing and viral shedding”.

As with all vaccines, we try to compile enough information to help owners make the best decisions for their pets. Here is what we can say with regard to canine influenza:

  • This virus (H3N8) jumped from horses to dogs in 2004. It has been moving across the country since then. Dogs involved in the racing industry have been the most severely affected due the high density housing and high stress conditions. This virus only affects dogs and cannot be transmitted to people or cats.
  • It is unclear if there is any significant incidence of this virus in Maryland. It has been documented in Virginia and Pennsylvania. Unfortunately, reliable independent surveillance information is not available.
  • As with human flu, this virus can be spread through contact with infected dogs. Rapid spread is more likely to occur in high density housing such as in animal shelters, kennels, or dog shows. This does not mean that the virus will spread rapidly through the rest of the community and harm the general population. Remember, this virus has been making its way around the country without terrible problems in the general population of dogs.
  • The majority of infected dogs develop mild signs characterized by cough similar to kennel cough. The problem resolves after 1-4 weeks without treatment. A much smaller percentage of dogs develop severe signs characterized by fever and pneumonia. These dogs can require more treatment to resolve the infection. Unfortunately, a small (1-5%) mortality rate is associated with this form of the disease. As with people, fatalities are more likely in patients with a compromised immune system, in high stress/high density housing, the very young, and the very old.
  • Based on the manufacturer’s study of 746 dogs, the vaccine appears to be safe. Although this type of vaccine (killed virus) is generally safe, sometimes our full understanding of any problems related to a biological product do not become apparent until it is in full use.
  • Due to the lack of risk to the general population at this time, we are not recommending this vaccine for every dog. If your dog is likely to be in high density housing, such as a boarding kennel or doggie day care, vaccination is a reasonable precaution. Dog parks are unlikely to carry great risk. This recommendation is in line with the American Veterinary Medical Association’s current position

Many boarding facilities are beginning to require this vaccine. To be effective, the vaccine requires a booster 2 to 4 weeks after the initial vaccination. To ensure full protection, it is important to complete the vaccinations prior to entering the boarding facility.

Additional information can be found at the following websites:

Backgrounder: Canine Influenza (American Veterinary Medical Association)

CDC Key Facts About Canine Influenza

University of Florida Canine Influenza FAQ By Dog Owners


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