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

An attending veterinarian has confirmed a horse with respiratory equine herpesvirus (EHV) at a Montgomery County, Maryland, boarding facility. An additional 60 horses have been exposed, and all are now under a voluntary quarantine, according to a March 5, 2020, Equine Disease Communication Center report.

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 infection is fever, which can go undetected. In addition to fever, other common signs of EHV 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