The Virginia Department of Agriculture and Consumer Services (VDACS) reported June 30 that it has received a report of the first case of Eastern equine encephalitis (EEE) in a Virginia horse this year.

The horse, a Saddlebred mare from Suffolk, began exhibiting clinical signs of disease June 22 and was euthanized June 23. Her vaccination record is unknown.

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.

Last year Virginia had three reported equine EEE cases—one from Suffolk and two from Chesapeake.

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In March, the VDACS encouraged horse owners to work with their veterinarians to plan a vaccination schedule that would protect their horses from EEE and West Nile virus (WNV), another mosquito-borne disease. Available vaccines are generally effective in reducing the incidence of both EEE and WNV in horses. For the vaccine to be effective it must be handled and administered properly and be given