The Equine Disease Communication Center (EDCC) has reported that a new case of Eastern equine encephalitis (EEE) was confirmed in a Washington County, Florida, horse on July 20.

“The adult pony had no known vaccine history and no recent travel history,” the EDCC said in a statement. “Clinical signs began on July 9 and the horse was euthanized for humane reasons the same day. This is the second confirmed EEE case in Washington County and case 13 in Florida for 2016.”

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.

Horse owners should also consult their private practicing veterinarian to determine an appropriate disease prevention plan for their horses. Vaccines have proven to be a very effective prevention tool. Horses that have been vaccinated in past years will need an annual booster shot. However, if an owner did not vaccinate their animal in previous years, the horse will need the two-shot vaccination series within a three- to six-week period