The Virginia Department of Agriculture and Consumer Services (VDACS) has reported the second case of Eastern equine encephalitis (EEE) in a horse in the commonwealth this year.

The horse, a 3-year-old Tennessee Walker mare, was from Chesapeake and was purchased by the current owner three weeks ago. Her vaccination history is unknown.

The mare began exhibiting signs of disease on Aug. 13 and was euthanized Aug. 14 due to the severity of the illness. The VDACS received confirmation from the National Veterinary Services Laboratory in Ames, Iowa, on Aug. 21. Both cases of EEE this year have been in horses from Chesapeake.

“One of the reasons most veterinarians recommend a six-month vaccination schedule in Tidewater Virginia is because of the prevalence of mosquitos in the area,” said State Veterinarian Richard Wilkes, DVM.

Wilkes explained that EEE, a mosquito-borne illness, causes inflammation or swelling of the brain and spinal cord and is sometimes called "sleeping sickness.” Clinical signs include impaired vision, aimless wandering, head-pressing, circling, inability to swallow, irregular staggering gait, paralysis, convulsions, and death. Once a horse has been bitten by an infected mosquito, it can take three to 10 days for signs of the disease to appear.

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Last year Virginia had one reported case of EEE, in a horse from Suffolk. The disease has a mortality rate of 80 to 90%, so prevention is