Eastern equine encephalomyelitis (EEE) is a virus that is spread by mosquitoes and causes “sleeping sickness” in horses. It has been confirmed in nine N.J. horses on eight premises as of Oct. 1, according to New Jersey’s Department of Agriculture’s Equine Epidemiologist Janice Nicol, DVM, MS.

None of the confirmed EEE positive horses, which include three Standardbreds, four Thoroughbreds, one pony, and one Quarter Horse, had a history of EEE vaccination. Nicols recommends vaccinating against EEE and administering a booster vaccination if the horse has not been vaccinated in the past six months, even though the mosquito populations have generally been low on the Eastern Shore this summer.

The disease occurs most often during late summer and early fall, until the frosts and freezing weather kill the mosquitoes