A second North Carolina horse has tested positive for Eastern equine encephalitis (EEE), the Equine Disease Communication Center (EDCC) reported July 11.
“On Wednesday, July 11, the North Carolina Department of Agriculture and Consumer Services confirmed … EEE in a 13-year old unvaccinated female chestnut draft mix located in Onslow County,” the EDCC said. “This is the second case of EEE in North Carolina for 2018.”
A viral disease, EEE affects the central nervous system and is transmitted to horses by infected mosquitoes. Clinical signs of EEE include moderate to high fever, depression, lack of appetite, cranial nerve deficits (facial paralysis, tongue weakness, difficulty swallowing), behavioral changes (aggression, self-mutilation, or drowsiness), gait abnormalities, or severe central nervous system signs, such as head-pressing, circling, blindness, and seizures. The course of EEE can be swift, with death occurring two to three days after onset of clinical signs despite intensive care; fatality rates reach 75-80% among horses. Horses that survive might have long-lasting impairments and neurologic problems. Once a horse has been bitten by an infected mosquito, it can take three to 10 days for clinical signs to develop.
Vaccines have proven to be a very effective EEE prevention tool. Equids that have been vaccinated in past years will need an annual booster shot. Unvaccinated horses, ponies, donkeys, and mules, or those with an unknown vaccination history, will need the two-shot vaccination series within a three- to six-week period.
In a statement issued after the state’s first EEE case of the year, confirmed earlier this week, State Veterinarian Doug Meckes, DVM, said he recommends a booster shot every six months in North Carolina because of the state’s prolonged mosquito season.
In addition to vaccinations, horse owners also need to reduce the mosquito populations and their possible breeding areas. 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. Additionally, owners can keeping animals inside during the bugs’ main feeding times, which are typically early in the morning and evening, and apply mosquito repellents approved for equine use according to manufacturer recommendations.