Three additional Standardbred horses tested positive yesterday for the equine herpes virus, or EHV-1, at The Meadows in Western Pennsylvania. Two additional horses at the race track were tested but results proved negative for the virus. As a precautionary measure, the track has suspended racing through Wednesday and will re-evaluate the status of new cases and racing options later this week.
State veterinarians have quarantined a total of 190 horses in five barns at The Meadows Racetrack and Casino in Washington County, and no horses will be moved in or out of the racetrack for now. Trainers continue to monitor three horses in the quarantined barns that presented with elevated temperatures. Officials acknowledge the inconvenience of the quarantine and disruption of the races, but remain hopeful that the outbreak appears to be confined to the track, thanks to cooperation from horse owners, trainers and track officials.
Late last week, three separate horses at the Washington County Fairgrounds were exhibiting suspicious symptoms, but their test results came back negative. There are no restrictions on the county fairgrounds.
Earlier in the week, a Washington County horse tested positive for EHV-1 at the Ohio State College of Veterinary Medicine, after displaying neurological symptoms at the track. Veterinarians report that the horse is responding well to treatment in Ohio.
EHV-1 is a highly contagious virus commonly found in horse populations. Depending on the specific strain of the virus, the equine herpes virus can cause a variety of clinical signs in infected horses, including respiratory disease or abortion in pregnant mares. The EHM form of the disease can cause paralysis and ataxia in horses; in severe cases, the infected horse may be euthanized. EHV-1 can cause illness in horses, other equine animals and camelids (llamas and alpacas); it does not pose a health threat to people or other animals.
Unless a new case is detected, horses can be cleared after 28 days without symptoms, or after 21 days with confirmation of negative test results for both blood samples and nasal swab tests.
Many horses carry a latent form of the herpes virus; symptoms may not appear unless the animal is stressed. There is no existing vaccine for the EHV-1 strain of the equine herpes virus.
To learn more about equine herpes, see the American Association of Equine Practitioners.