On Sept. 9 the Virginia Department of Agriculture and Consumer Services (VDACS) confirmed the first case of Eastern equine encephalitis (EEE) in a horse this year.

The horse, a 7-year-old Paint gelding from Disputanta in Prince George County, moved to Virginia from Mississippi three months ago; a blood test showed recent infection, indicating he contracted the disease in Virginia. The horse had not received an EEE vaccination and was euthanized on August 31.

This is the first reported case of EEE in a horse in Virginia this year. Last year the state had eight cases of equine EEE, most of them from the Tidewater area. So far there have been no reported cases of West Nile virus (WNV)—another mosquito-borne disease—in Virginia horses this year.

In an April 2013 press release, Richard Wilkes, DVM, VDACS’ state veterinarian, encouraged horse owners to work with their veterinarians to plan a vaccination schedule that would protect their horses against EEE. Commercially available vaccines are effective in drastically reducing the incidence of both EEE and WNV in horses. The vaccines are effective for six to 12 months, so horses should be vaccinated at least annually. In an area where the disease occurs frequently, many veterinarians recommend vaccination every six months