RALEIGH – Two Quarter horses were euthanized this month after contracting Eastern Equine Encephalomyelitis, a mosquito-borne disease that is preventable in equine by vaccination.
The unvaccinated horses, one a 2-year-old Robeson County mare and the other a 7-year-old stallion from Bladen County, exhibited signs of generalized weakness, stumbling, depression and inability to stand or eat.
They are the first reported cases of EEE in horses this year. Last week, New Hanover County officials reported that EEE was found in a sentinel chicken flock.
“If your horses exhibit any symptoms of EEE, contact your veterinarian immediately,” said State Veterinarian David Marshall. “Several serious contagious diseases, such as Equine Herpes Virus and rabies, have similar symptoms and should be ruled out.”
EEE causes inflammation or swelling of the brain and spinal cord and is often fatal. Symptoms of EEE include impaired vision, aimless wandering, head pressing, circling, inability to swallow, irregular staggering gait, paralysis, convulsions and death. Once a horse has been bitten by an infected mosquito, it may take three to 10 days for signs of the disease to appear.
In Robeson County, the horse deteriorated so quickly that it was euthanized within 24 hours of first exhibiting symptoms. The Bladen County horse had symptoms for several weeks before being euthanized earlier this month. Testing at Rollins Laboratory confirmed EEE this week.
Marshall recommends that equine owners talk to their veterinarians about an effective vaccination protocol to protect horses from EEE and another mosquito-borne disease, West Nile Virus. The EEE and WNV vaccinations initially require two doses for horses, mules and donkeys that have no prior vaccination history.
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 virus to other horses, birds or people through direct contact.
Dr. Tom Ray, director of livestock health
NCDA&CS Veterinary Division