Horse Health

Equine Influenza Virus

April 28, 2011

Learn more about how to help prevent this common infectious disease.

From AQHA Corporate Partner Pfizer Animal Health

Young horses are especially susceptible to the equine influenza virus. Journal photo.

Equine Influenza Virus
Equine influenza virus (FLU) is one of the most common infectious diseases affecting the respiratory tract in horses. According to the American Association of Equine Practitioners, it commonly occurs in horses in the United States and throughout much of the world, with the notable exceptions of New Zealand and Iceland1.

What Is Equine Flu?
Equine influenza is a virus of the H3N8 subtype. Two different H3N8 subtypes appear in circulation internationally2. It is important to note that these are different than the flu strains affecting humans, and at this time, equine influenza viruses have not been reported to infect people.

Are Young Horses More Susceptible to Equine Influenza?
Horses ages 1 to 5 can be more susceptible, while older horses are less susceptible to an equine influenza virus infection. However, it is important to keep in mind that immunity can be compromised in any horses that are frequently exposed at shows and other events1.

Your horse’s health is important to you. To stay on top of it and keep up-to-date on health information, check out our Common Horse Health Issues report. You’ll find information about strangles, West Nile virus, colic, laminitis, EPM and more!

What Are Symptoms of Equine Influenza?
Flu symptoms in horses can include elevated body temperatures, loss of appetite, harsh dry cough, depression and nasal discharge.

How Is Equine Flu Transmitted?
Equine influenza is highly contagious and can be spread by a couple different means. The first is through respiratory tract secretions. Coughing horses can release the virus into the air, where it is spread up to 30 to 50 meters2. It can also be spread by direct contact between horses and indirectly via a person’s hands or clothing or on inanimate objects such as buckets, tack or lead ropes2.

How to Help Protect Your Horse From Flu?
The best measure for helping protect horses against influenza is to have them vaccinated by a veterinarian. FLUVAC INNOVATOR® — a Fort Dodge vaccine offered by Pfizer Animal Health — helps provide protection against equine influenza virus. The FLUVAC INNOVATOR vaccines, along with other Pfizer Animal Health equine vaccine combinations, are included in the Equine Immunization Support Guarantee.

The Pfizer Animal Health Equine Immunization Support Guarantee provides up to $5,000 for reasonable diagnostic and treatment costs if a horse properly vaccinated by a veterinarian contracts the corresponding equine disease. Disease protection backed by the Equine Immunization Support Guarantee includes infection from West Nile virus, equine influenza virus, tetanus, eastern equine encephalitis virus, western equine encephalitis virus and Venezuelan equine encephalitis virus. Vaccinations must be performed by a licensed veterinarian with an established client-patient relationship to be eligible.

It’s always important to be prepared for any kind of medical emergency. Let AQHA help with our Common Horse Health Issues report. It will help you learn more about common health issues horse owners face.

Practicing good barn hygiene, both at home and on the road can also help protect your horse from infection or reduce the spread of infection. Whenever possible, avoid sharing water buckets, lip chains, halters or other items that touch the horse’s mouth or nose. If items have to be shared, be sure to follow proper sanitation and disinfection techniques first. Veterinarians recommend that every barn offer a shallow basin filled with properly mixed disinfectant for people to wash their shoes before entering or leaving a facility.

When Should Horses Be Vaccinated Against Equine Influenza?
According to the AAEP vaccination guidelines, adult horses, previously vaccinated, should be revaccinated at six-month intervals. This includes performance, show or pleasure horses constantly at risk of exposure1. For further vaccination guidelines, horse owners should consult a veterinarian, as guidelines may vary between products, age and use of the horse.

References:

1. Equine Influenza. American Association of Equine Practitioners. 2008. Available at: http://www.aaep.org/equine_influenza.htm. Accessed on March 24, 2011.

2. Bug of the Month: Equine Influenza Virus. Equid Blog University of Guelph.Posted December 11, 2010. Available at: http://www.equidblog.com/2010/12/articles/another-category/influenza/bug-of-the-month-equine-influenza-virus/. Accessed on March 24, 2011.

3. Ostlund EN. The Equine Herpesviruses. Vet Clin North Am Equine Pract. 1993 Aug: (9)2:283-294