A quarantine at Rolling Hills Ranch stable in Bridgeville, Allegheny County, Pa., has been lifted after samples collected from all 116 horses there tested negative for the neurologic form of equine herpesvirus-1, or EHV-1, said Agriculture Secretary Dennis Wolff .

The quarantine was established on July 20 when at least three horses tested positive for the neurologic form of EHV-1. The movement of horses at the stable was restricted to stop the spread of the disease.

Consistent with the quarantine order, 21 days passed, beginning Aug. 1, without any horses exhibiting signs of EHV-1.

Six horses were euthanized between July 17 and July 31 because they displayed clinical signs consistent with the neurologic form of EHV-1 including loss of coordination, weakness or paralysis of the hind limbs, and incontinence