Equine Influenza: Protecting Your Horse

Equine influenza is the most common contagious illness of horses in the Fraser Valley. It affects the airways and causes horses to suffer with a fever, poor appetite and runny nose. Horses with the flu usually feel sick for one to two weeks before recovering. The damage caused to the airways by equine influenza virus often results in a cough that lasts up to three months and seriously hinders training or competition.

The flu is highly contagious and is spread through contact, buckets, tack, and on people’s skin and clothing. Once one animal catches the flu, it rapidly spreads throughout the barn to other unvaccinated horses.  Young horses, very old horses or stressed horses are most likely to become sick with the flu. Horses that go to the racetrack and those that go out for breaking, training or showing are most likely to suffer from the flu and bring it home to stablemates.

Traditionally, we have used an injectable vaccine given every 4 months to try to prevent equine influenza. However, in the 1990’s, research at the Western College of Veterinary Medicine proved that vaccinated horses were getting sick with the flu. This led to the development of new, more effective vaccines. In Canada, two licensed vaccines have been proven to protect horses against the flu for at least six months after vaccination.

FluAvert IN has been shown to provide excellent protection against influenza. It is designed to be administered intranasally by a veterinarian and stimulates the immune system in the airways to produce antibodies against the influenza virus. When a horse is exposed naturally, the immune system reacts quickly and prevents the virus from setting up an infection and causing disease.  Fluavert is designed to be given every six months.

Calvenza is the newest vaccine available against influenza. Calvenza is a dual vaccine against influenza and rhino (equine herpes virus 1). It has been shown to provide excellent protection against the flu, but has only been shown to provide three weeks protection against rhino.  Initially, two vaccines are administered three weeks apart, and then a single vaccination is given every 6 to 9 months to provide ongoing protection against influenza. Calvenza can be given to pregnant mares 1 month before foaling to provide high antibody levels against influenza in colostrum, protecting foals for the first six months of life.

If you are interested in developing an up to date vaccination program for your horses, or to book an appointment for to vaccinate your horse against “the flu” please contact the clinic.

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