Equine Cases of EEE and WNV in Virginia

Posted: November 12, 2007

Eastern equine encephalitis and West Nile virus are transmitted by mosquitoes.

Virginia's state veterinarian confirmed on Wednesday (July 24) the first cases of Eastern equine encephalitis (EEE) and West Nile virus (WNV) in horses this year. The EEE-positive horse was from Suffolk and was euthanatized because of its illness on June 26. The WNV-positive horse is from Rockingham County, and developed clinical signs on June 23. That horse has since recovered. In 2006, there were no equine cases of EEE in Virginia, and only one case of WNV in a Virginia equine, in Suffolk.

The state veterinarian urges horse owners to vaccinate all equines every six to twelve months against these diseases. This is particularly important in the southeastern region of Virginia, where many equine veterinarians already recommend the six-month vaccination interval.

Generally, both EEE and WNV are transmitted by mosquitoes. Typical clinical signs include staggering, circling, depression, loss of appetite, and sometimes fever and blindness. There is no cure for the disease (only supportive care), but it can be prevented through vaccination. Other prevention methods include destroying standing water breeding sites for mosquitoes, use of insect repellents, and removing animals from mosquito-infested areas during peak biting times, usually dusk to dawn.

For more information, Virginia residents should contact the Office of the State Veterinarian at (804) 692-0601 or consult their local veterinarians.