Notification: Equine Infectious Disease at Cornell's Equine Park; the Equine Hospital is not impacted and remains open
On Tuesday March 6th, a Cornell University teaching and research horse named Salty housed in M-Barn (separate from the teaching hospital) developed neurological signs and was confirmed to have Equine Herpes Virus-1 (EHV-1) that same day at the New York State Animal Health Diagnostic Center’s Molecular Laboratory. All horse movement amongst Cornell equine facilities was immediately stopped and an investigation of horses in direct contact over the preceding week led us to conclude that only the Cornell teaching and research horses were possibly exposed to the virus. The Equine and Nemo Farm Animal Hospital along with our client-owned animals were not considered in-contact and therefore not at risk. In addition, the Oxley Equestrian Center was not involved.
Communication with Dr. Mangano at the New York State Agriculture and Markets decided that a 3-week quarantine (up to March 29) of the Equine Park horses (approximately 50 horses) in the following facilities (1) M and L Barns (2) Equine Park on Blue Grass Lane and (3) Equine Annex on the corner of Snyder Hill and Pine Tree Roads should be undertaken to protect these horses and the community. The horses in closest contact (M-barn) with the neurological horse are being treated with an antiviral (valacyclovir).
Over the past week, the Cornell horses have been outwardly healthy with one horse having a fever on Saturday March 11 which was negative for EHV-1 on a nasal swab PCR test. We hope that the neurological case will be an isolated incident but will continue to closely monitor the herd to detect any further cases if they occur.
The single horse in the Cornell herd with Equine Herpes Myelitis (EHM), the neurological form of EHV-1, is presumed to be from recrudescence of the virus. EHV-1, an alpha-herpes virus, and like all herpes viruses establishes latency in the horse. The latent virus is dormant while the immune system is strong and can reactive or recrudesce in times of stress. This reactivation leads to shedding of virus from the nose with little to no outward clinical signs, or in some instances can lead to fever, nasal discharge, decreased appetite, lethargy, neurological signs and in pregnant mares’ abortion. The Cornell Equine Park horse had recently been transported, grouped with different horses in a barn and started on a research project. Since we had not obtained any new horses in the past few months, we feel that these stresses, combined with the horse’s reduced immune status led to reactivation of the virus and then EHM. Unfortunately, the neurological signs progressed, and Salty could no longer rise and had changes in mentation which led to euthanasia. We are very saddened to lose Salty, this gem of a horse – as she was always first to the gate to say hello and was very patient teaching our veterinary students.
Our prompt actions and continued quarantine should protect the surrounding equine community and our hospital. If you have any questions or concerns, please contact Dr Gillian Perkins at 607.253.3100.
Please note that EHV-1 is mostly spread through direct nose-to-nose contact from horse to horse. As a virus that establishes latency, its survival is within the horse. While an infected horse that is shedding from the nose, can leak virus onto various stable surfaces (buckets, lead shanks, halters, etc) or personal clothing. And then another horse, that comes in close contact and inhales virus form these sources could become sick. This mode of transmission is possible, yet less likely to happen. To protect your horse from EHV-1 continue to stay up to date on equine vaccines in consultation with your veterinarian and always use care when handling horses outside of your farm. If your horse becomes sick and has a fever call your veterinarian to evaluate the likely cause along with treatment and management plan.
For further information on Equine Herpes Virus-1 please visit the following recommended sources:
The Cornell Equine Park is the "hidden gem" of the College of Veterinary Medicine with 165 acres of green pastures and multiple barns, all less than two miles from the College. The entire facility is a learning lab for DVM students and researchers, with the horses as the teachers.
The horses are really the teachers here, more so than the people. Everything that they do at the Park fulfills a teaching mission. They help train DVM students no matter which branch of veterinary medicine they decide to pursue.