The New Jersey Department of Agriculture has quarantined a property in Sussex County after two horses developed the highly infectious equine herpes myeloencephalopathy (EHM).

One horse, a seven-year-old Standardbred mare, developed illness on Oct. 1, 2023, and improved clinically after prompt medical treatment. Six days later a second horse, a three-year-old Standardbred mare developed clinical signs of fever and recumbency and was humanely euthanized due to severe clinical deterioration.

EHM is the often-deadly neurologic form of Equine Herpes Virus (EHV-1) infection. Other horses on the premises are under quarantine. Temperatures are also being taken twice daily on all quarantined horses to monitor for sickness. The NJDA is tracing and notifying the appropriate parties regarding recent horse movement.

“The Department quickly took the necessary steps in an effort to stop the disease from spreading by placing a quarantine on the movement of other horses to and from the property,” said Joseph Atchison III, New Jersey Assistant Secretary of Agriculture. “These preventative measures are vital in containing what is a highly contagious virus for horses.”

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 of EHV-1 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, clinical signs typically include mild incoordination, hind end weakness/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.

The virus is endemic in the country and although highly infectious, it does not persist in the environment for an extended period and is neutralized by hand soap, alcohol-based hand sanitizers and sunlight. The virus does not affect humans and other domestic animals, except for llamas and alpacas. The first case of EHV-1 in New Jersey was confirmed in September in Gloucester County.

The NJDA Animal Health Diagnostic Laboratory is available to assist veterinarians with EHV-1 testing. For contact information, visit the lab website at jerseyvetlab.nj.gov. Concerned owners should consult with their veterinarian prior to taking any action as the clinical signs of infection with the neurological form of EHV-1 (EHM) are common to many other diseases. EHM is a reportable disease in New Jersey.  If an owner has a horse exhibiting neurologic signs or suspects Equine Herpes, they are directed to call their veterinarian immediately.

(New Jersey Department of Agriculture)