The Maine CDC reported on Aug. 30 that it received positive test results for Eastern equine encephalomyelitis (EEE) in a York County horse. This is Maine’s first confirmed equine case of EEE since 2013. | Photo: Wikimedia Commons

Said Michele Walsh, DVM, state veterinarian with the Maine Department of Agriculture’s (MDA) Division of Animal Industry (DIA), the unvaccinated yearling Quarter Horse colt presented on Aug. 22 with clinical signs that included fever followed by acute, progressive neurological symptoms. The attending veterinarian euthanized the horse on Aug. 23 and reported the case to the Maine Department of Agriculture, Conservation and Forestry, who pursued testing.

“Vaccination and environmental mitigation (minimizing areas where mosquitoes can breed and hatch) remain the best prevention,” Dr. Walsh said.

EEE 101

Eastern equine encephalomyelitis is caused by the Eastern equine encephalitis virus, for which wild birds are a natural reservoir. Mosquitoes that feed on EEE-infected birds can transmit the virus to humans, horses, and other birds. Horses do not develop high enough levels of these viruses in their blood to be contagious to other animals or humans. Because of the high mortality rate in horses and humans, EEE is regarded as one of the most serious mosquito-borne diseases in the United States