(Updated 3/07/03) Ohio and Pennsylvania have confirmed or reported cases of the neurologic form of equine herpesvirus type 1. But the worst problems reported thus far have occurred in Ohio, where 12 horses died in an outbreak at the University of Findlay (see article #4127) and three other Ohio horses died from exposure to those initial cases. Tests are being done to compare the Ohio virus to isolates from past EHV-1 outbreaks to determine if the Ohio virus is especially virulent. The virus is thought to have spread from Findlay horses being treated at The Ohio State University (OSU) to other horses being treated there from Jan. 18-Feb. 11.

The EHV-1 organism can cause three different forms of disease, including rhinopneumonitis (a respiratory disease often affecting young horses), abortions in pregnant mares, and neurologic disease. Horses in the Ohio and Pennsylvania outbreaks have shown fevers, respiratory illness, and neurologic deficits. There are at least seven other strains of equine herpesviruses. Horses can survive the neurologic form of EHV-1 with supportive care, but if a horse becomes recumbent (stays down), it is difficult to nurse the horse back to health. The virus doesn’t live long in the environment, and it can be killed with bleach