n many horses, the first or only sign of EHV-1 infection is fever, which can go undetected. | Photo: Stephanie L. Church/The Horse

An attending veterinarian has confirmed the neurologic form of equine herpesvirus (EHV) in a horse at a Foothills County, Alberta, Canada, facility. The horse presented with acute neurologic signs and was treated for two weeks, then euthanized after showing no improvement. Two additional horses at the stable were exposed but have shown no clinical signs and have been placed under a three-week quarantine.

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 equine herpesvirus myeloencephalitis (EHM, the neurologic form).

​In many horses, the first or only sign of EHV-1 infection is fever, which can go undetected. In addition to fever, other common signs of EHV-1 infection in young horses include cough, decreased appetite, depression, and a nasal discharge. Pregnant mares typically show no signs of infection before they abort, and abortions usually occur late in gestation (around eight months) but can be earlier. Abortions can occur anywhere from two weeks to several months following infection with EHV-1