The Virginia Department of Agriculture and Consumer Services (VDACS) has confirmed the first case of Eastern Equine Encephalitis (EEE) in a Virginia horse this year. The horse, from Suffolk, was a Saddlebred mare. She exhibited symptoms on June 22 and was euthanized June 23.
In North Carolina, a Pitt County quarter horse has been confirmed as having died after contracting EEE. The disease is a mosquito-borne and preventable in equine by vaccination.
The horse exhibited signs of generalized weakness, stumbling, depression and inability to stand or eat. This is the first reported case of EEE in North Carolina this year, however two cases have already been confirmed in South Carolina.
Eastern Equine Encephalitis causes inflammation or swelling of the brain and spinal cord. The disease is also called “sleeping sickness.” Symptoms include impaired vision, aimless wandering, head pressing, circling, inability to swallow, irregular staggering gait, paralysis, convulsions and death. Once an infected mosquito has bitten a horse, it may take three to 10 days for signs of the disease to appear.
Last year Virginia had three reported cases of EEE, one from Suffolk and two from Chesapeake. The disease has a mortality rate of 80 to 90 percent, so prevention is a key part of equine health. Vaccination and mosquito control and avoidance are the central elements of prevention.
“If your horses exhibit any symptoms of EEE, contact your veterinarian immediately,” said State Veterinarian Doug Meckes. “And if your horses aren’t vaccinated, talk to your veterinarian about vaccinating all of your equine as soon as possible against EEE and West Nile Virus.” The vaccinations initially require two shots, 30 days apart, for horses, mules and donkeys that have no prior vaccination history. Meckes recommends a booster shot every six months in southern states because of a prolonged mosquito season.
Mosquitoes can breed in any puddle that lasts for more than four days; so removing any source of standing water can reduce the chance of exposing animals to WNV or EEE. Keeping horses in stalls at night, using insect screens and fans and turning off lights after dusk can also help reduce exposure to mosquitoes. Insect repellants can be effective if used according to manufacturers’ instructions.
People, horses and birds can become infected from a bite by a mosquito carrying the diseases, but there is no evidence that horses can transmit the viruses to other horses, birds or people through direct contact.