
On April 17, a 2-year-old draft horse stallion in Elkhart County, Indiana, was diagnosed with equine herpesvirus myeloencephalopathy (EHM). The affected horse is currently under quarantine, and two other horses are suspected to be infected as well.
EDCC Health Watch, sponsored by the Equine Network, provides verified equine disease reports sourced from the Equine Disease Communication Center (EDCC). The EDCC is a non-profit organization that relies on industry donations to offer accessible infectious disease information.
Understanding EHV
Equine herpesvirus (EHV) is highly contagious and can lead to various health issues in horses, including respiratory problems, abortion in pregnant mares, and EHM.
Fever is often the initial symptom of EHV-1 infection in horses, which can sometimes go unnoticed. Other common signs include coughing, reduced appetite, lethargy, and nasal discharge. Pregnant mares may not display any symptoms before experiencing a late-term abortion, which typically occurs around eight months of gestation but can happen earlier. Abortions can take place anywhere from two weeks to several months after EHV-1 infection.
Horses with EHM typically start with a fever and may exhibit respiratory symptoms. Neurological signs like incoordination, limb weakness or paralysis, urinary issues, tail tone loss, and recumbency usually appear a few days later.
EHV spreads easily through direct contact with infected horses, sharing contaminated equipment or clothing, and contact with individuals who have been in proximity to infected animals. Adhering to biosecurity measures such as proper hygiene and equipment disinfection is crucial in preventing disease transmission.
While current EHV-1 vaccines may reduce viral shedding, they do not offer protection against the neurological form of the disease. Prioritizing biosecurity practices is key to minimizing the spread of the virus, with disease prevention being the most effective method of control.

