Timing of vaccinations critical to protect horses from encephalitis

Horses vaccinated after late March should be protected, but those vaccinated prior to March should receive an EEE booster, she said.

EEE is a vector disease, which means it cannot be transmitted from horse to horse. In EEE, mosquitoes are the vectors, or carriers, that transmit the disease to horses. The disease can result in death.

Early foaling broodmares that were vaccinated early on should get a booster to provide protection to their foals. Additionally, owners who think a yearly vaccination can be done anytime of the year should give their horses a booster, Marteniuk said.

The vaccine should be effective for six to eight months.

“There have been cases of horse fatalities in Michigan because the owner was vaccinating for EEE in the fall, and the horses were not protected during the entire mosquito season,” Marteniuk said. “It’s important that owners consult with their veterinarians to ensure proper timing of vaccines and other health protocols.”

Most horses that have developed the disease in Michigan were not vaccinated. For those horses not vaccinated, owners can vaccinate now to ensure horses are protected for the remainder of the season, Marteniuk said.

Karen Waite, MSU Extension equine specialist, frequently works with horse owners around the state.

“If you have a horse and are unsure of its vaccination history, you should re-vaccinate them to be sure they are protected,” she said.

Marteniuk said the first seven to 10 days after vaccination are the most critical period, since the horse could still become infected. She also advised that any horse not vaccinated in the past one to two years should receive a booster two weeks after the initial vaccination, rather than waiting the usual three to four weeks according to routine vaccination protocol.

EEE is also transmittable from mosquitoes to humans, and because of the high mortality rate among horses and people, is regarded as one of the most serious mosquito-vectored diseases in the United States.

The Michigan departments of Community Health and Agriculture encourage people to take precautions when EEE has been identified in horses or people in their area. Recommended measures include applying mosquito repellent, repairing or replacing broken window screens and draining standing water sources.

“A simple vaccination will protect your animal from these often fatal illnesses, and routine measures to reduce mosquito exposure and eliminate mosquito habitats around the home and farm will help protect people, horses and other livestock,” state veterinarian Dr. Steven Halstead said in a news release issued jointly by MDA and MDCH.

To find out more information on EEE and vaccinations or to develop a horse health program, contact your local veterinarian.

Provided by Michigan State University (news : web)