Sussex County horse euthanized after testing positive for equine herpes virus

SUSSEX COUNTY, N.J. — The New Jersey Department of Agriculture has quarantined a property in Sussex County, exact location not released, after one horse developed the highly infectious equine herpes myeloencephalopathy (EHM).

The horse, a 20-year-old mare, developed acute clinical signs on Aug. 3 and was subsequently humanely euthanized. One week earlier, another horse on the property presented with similar neurological signs and was also euthanized without diagnostic testing. EHM is the often-deadly neurologic form of equine herpes virus (EHV-1) infection. The remaining horse on the premises is under quarantine and being monitored for sickness. No recent horse movement has occurred by this herd, making the risk of disease spread from this case very low.

“The Department took swift action to prevent the disease from spreading to other horses by enacting a quarantine, which stops movement of horses in and out of the properties and puts in place preventive measures to contain the virus,” said New Jersey Secretary of Agriculture Edward Wengryn.

The EHV-1 organism spreads quickly from horse to horse and can cause respiratory problems, especially in young horses, spontaneous abortions in pregnant mares, and the neurologic form of the virus can result in death. The incubation period is typically two to 10 days. Clinical signs include respiratory disease, fever, nasal discharge, depression, cough, lack of appetite, and/or enlarged lymph nodes. In horses infected with the neurologic strain of EHV-1, signs may include mild incoordination, hind-end weakness or paralysis, loss of bladder and tail function, and loss of sensation to the skin in the hind end.

The virus spreads readily through direct contact with infected materials but does not persist in the environment for an extended period and can be neutralized by hand soap, alcohol-based hand sanitizers, and sunlight. It does not affect humans or other domestic animals, except for other equidae and camelids such as llamas and alpacas.

The NJDA Animal Health Diagnostic Laboratory is available to assist veterinarians with EHV-1 testing. Concerned owners should consult with their veterinarian before taking any action, as symptoms of EHM can be similar to other diseases. EHM is a reportable disease in New Jersey, and owners with a horse exhibiting neurologic signs or who suspect equine herpes are directed to call their veterinarian immediately.