Vaccinate Horses To Prevent Mosquito-borne Diseases

Steven S. Nicholson, Coolman, Denise  |  4/19/2005 10:29:02 PM

News Release Distributed 09/14/04

Horse owners who have not had their animals vaccinated against Eastern Equine Encephalitis are encouraged to do so to prevent the disease, according to LSU AgCenter veterinarian Dr. Steve Nicholson.

The disease was discovered recently in horses in DeSoto and Calcasieu parishes.

"It is not unusual to have several horses in one area affected," Nicholson said. "It’s been a few years since an outbreak has occurred, so it’s not unexpected to have one now."

Nicholson said Louisiana horse owners need to protect their animals each year against Eastern Equine Encephalitis, Western Equine Encephalitis and West Nile virus.

The diseases are transmitted to horses by infected mosquitoes, and acute cases of some of these diseases can be fatal for the animals.

"Basic vaccination of adult horses should include annual or semi-annual booster shots for Eastern, Western and West Nile Virus encephalitis," Nicholson said.

Vaccinations will help protect horses from the diseases. But if a horse hasn’t been vaccinated in recent years, two shots are required for ultimate protection, the veterinarian said.

"These shots are given one month apart," Nicholson said. "So if a horse hasn’t been vaccinated in a few years, the owner will want to be sure to get these vaccinations done immediately."

Nicholson also said foals and colts of immunized mares should receive an initial series of the vaccine at 3 months to 6 months of age. Foals of unvaccinated mares can be vaccinated at 1 month and receive the booster monthly through 6 months of age. Horse owners should contact their veterinarians for specific advice, Nicholson advised.

It had not been confirmed as of Monday (Sept. 13) if another DeSoto Parish horse tested last week (Sept. 9) has Eastern Equine Encephalitis, but Nicholson said the horse has "all of the clinical earmarks of encephalitis." Tests on the horse are pending.

Two cases of Eastern Equine Encephalitis have been reported and confirmed in Louisiana. One was in DeSoto Parish and the other was in Calcasieu Parish.

For specific information, horse owners are urged to discuss encephalitis vaccinations and other disease vaccinations with their veterinarians.

In addition, information on Eastern Equine Encephalitis is available in the free LSU AgCenter publication, "Questions Regarding Eastern Equine Encephalitis and Horses," which can be obtained through parish LSU AgCenter Extension offices or on the Web at:


Contact: Steve Nicholson at (225) 578-2414 or
Writer: A. Denise Coolman at (318) 644-5865 or

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