The state veterinarian’s office of the Virginia Department of Agriculture and Consumer Services (VDACS) confirmed that a 20-year-old Thoroughbred mare tested positive for equine herpesvirus-1 (EHV-1) on Nov 20. Equine herpesvirus-1 is the virus that causes the neurologic form of equine herpesvirus, also known as equine herpesvirus myeloencephalopathy.

The mare had experienced onset of clinical signs, including ataxia (loss of control of body movements), recumbency (inability to rise), and vestibular (inner ear) signs, on Nov. 17. According to a she was admitted that day to the Virginia Maryland College of Veterinary Medicine (VMCVM) Large Animal Hospital in Blacksburg where she deteriorated and was euthanized Nov 18.

The Montgomery County farm where the mare resided and all exposed horses at the hospital were quarantined after being isolated and placed under strict biosecurity measures including monitoring twice daily for clinical signs and temperatures exceeding 101.5°F. The state veterinarian’s office has also contacted the owners of all other horses that may have been exposed secondarily at the hospital. The hospital remains open and able to admit and treat patients.

EHV 101

Herpesvirus is highly contagious among horses and can cause a variety of ailments in equids, including rhinopneumonitis (a respiratory disease usually found in young horses), abortion in broodmares, and EHM