The Vermont Agency of Agriculture, Food, and Markets was notified on Sept. 21 that a horse located in Pittsford, Vt., has tested positive for Eastern equine encephalitis (EEE). The horse began showing signs of illness on Sept. 16 and was euthanized the next day. The horse was not vaccinated against EEE. This is the second horse that tested positive for EEE in Vermont this year, and this is the first time the virus has been detected in the town of Pittsford.

A viral disease, EEE affects the central nervous system and is transmitted to horses by infected mosquitoes. Its fatality rate in horses is 75-95%. The course of EEE can be swift, with death occurring two to three days after onset of clinical signs despite intensive care. Horses that survive might have long-lasting impairments and neurologic problems. 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.

Vermont cases of EEE in animals are required to be reported to the Office of the State Veterinarian.

"All horses in Vermont should be vaccinated for EEE, regardless of their travel frequency" stated Shelley Mehlenbacher, DVM, MPH, Dipl. ACVPM, Vermont assistant state veterinarian. "Even horses that spend the majority of their time on isolated properties are susceptible, and those horses should be vaccinated. Horse owners and veterinarians should work together to develop appropriate vaccination plans