RALEIGH – A 4-year-old horse in Halifax County was recently euthanized after contracting Eastern Equine Encephalomyelitis, a mosquito-borne disease that is preventable in equine by yearly vaccination. It is the first reported case of EEE in horses this year.
“The number of reported EEE cases fluctuates each year,” said State Veterinarian David Marshall. “Late summer to early fall is peak mosquito season in North Carolina, and this is right on schedule for us to start seeing cases.”
North Carolina had 6 reported EEE cases in 2010, 23 in 2009 and 13 in 2008. It is estimated that for every reported case, four or more cases go unreported. There was one case last year of West Nile virus, another mosquito-borne disease that affects equine.
The EEE and WNV vaccinations initially require two shots, 30 days apart, for horses, mules and donkeys that have no prior vaccination history. Neither vaccination fully protects the animal until several weeks after the second shot, so it is best to vaccinate as early in the mosquito season as possible. Marshall recommends that horse owners talk to their veterinarians to determine the best time to start the vaccination process. He also recommends a booster shot of each vaccine be given every six months in North Carolina because of the extended mosquito season.
Symptoms of EEE include impaired vision, aimless wandering, head pressing, circling, inability to swallow, irregular staggering gait, paralysis, convulsions and death.
Symptoms of WNV in horses can include loss of appetite and depression, fever, weakness or paralysis of hind limbs, convulsions, impaired vision or hyperexcitability.
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.