A Maryland horse has tested positive for the neurologic form of the equine herpesvirus (EHV-1). The equine is stabled in Montgomery County and is being treated by a private veterinarian.
The Maryland Department of Agriculture (MDA) states the horse traveled outside the county to breed “for more than two weeks” before returning to its stable Monday. The horse began showing mild respiratory and neurological signs on Tuesday. A veterinarian reported the suspected case to MDA, as required by law. Lab tests confirmed the diagnosis. The horse’s condition is improving.
The neurologic strain is also called equine herpesvirus myeloencephalopathy (EHM). It is the mutant form of EVH-1. There is no vaccine currently on the market that has a label for prevention of the neurologic form of the disease.
EHV-1 can be spread through various methods. Direct, horse-to-horse contact is a common route of transmission, but indirect transmission is also possible. This occurs when infectious materials are carried between infected and non-infected horses by people or inanimate objects such as buckets, tack, or trailers. Aerosol transmission can also occur when infectious droplets are inhaled. The source of infectious droplets is most often respiratory secretions.
Symptoms may include respiratory disease, abortion, and intermittent outbreaks of neurologic disease in horses. Symptoms that should alert horse owners to the possibility of neurologic EHV-1 infection include fever, weakness, incoordination, and urine dribbling or inability to urinate. Horses with these symptoms should be examined immediately by a veterinarian.
The Maryland farm’s horses are being tested in addition to others that came in contact with the index case at the breeding facility. Two farms are under a state imposed quarantine for 28-days while MDA inspectors perform epidemiological and infectious disease testing.