Two North Carolina Quarter Horses were euthanized this month after contracting Eastern equine encephalomyelitis (EEE), a mosquito-borne disease that is largely preventable in equine by vaccination.

The unvaccinated horses–a 2-year-old Robeson County mare and a 7-year-old stallion from Bladen County–exhibited signs of generalized weakness, stumbling, depression, and inability to stand or eat. The Robeson County horse’s condition deteriorated so quickly that she was euthanized within 24 hours of first exhibiting clinical signs. The Bladen County stallion displayed signs for several weeks before being euthanized earlier this month; testing at Rollins Laboratory, in Raleigh, confirmed EEE this week.

They are the first reported cases of EEE in North Carolina 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, DVM. "Several serious contagious diseases, such as equine herpesvirus and rabies, have similar symptoms and should be ruled out