Horses at Rolling Hills Ranch stable in Bridgeville, Allegheny County, Pa., have been quarantined after at least three horses tested positive for the neurologic form of equine herpesvirus-1, or EHV-1, Agriculture Secretary Dennis Wolff said today.

“Equine herpesvirus causes upper respiratory infection and can cause severe neurological disease in horses,” said Wolff. “The quarantine was put in place to restrict the movement of horses from the stable and contain the virus.”

The quarantine covers the entire property, including five barns housing more than 100 horses. It will remain in effect until a period of 21 days has elapsed without relevant clinical signs in any horses. At that point, all horses will be tested for EHV-1 and the quarantine will be released when all horses test negative.

The attending veterinarian at Rolling Hills Ranch recognized clinical signs consistent with the neurologic form of EHV-1 in several horses and alerted the Bureau of Animal Health and Diagnostic Services on July 19