The Virginia Department of Agriculture and Consumer Services (VDACS) announced 2004’s first positive case of West Nile virus (WNV) in a horse on May 28. The six-year-old Thoroughbred mare lived on a farm in Culpeper County that had a positive case of WNV in 2003. She received one WNV vaccination only two weeks prior to the May 1 onset of clinical signs.

The mare exhibited the following clinical signs:

• toe dragging on all four feet;


• buckling at the knees;


• muscle fasciculations; and


• trouble eating, drinking, and controlling her tongue

She was sent to a veterinary referral hospital and despite intensive therapy, euthanasia was necessary after a few days of treatment due to the severity of the clinical signs.

This confirmation came earlier in the season than any of the previously-reported cases of WNV in Virginia. In 2003, VDACS reported the first positive case on July 25; in 2002, the first report was on Aug. 21 and in 2001, on Sept. 7