The New Mexico Department of Agriculture and the New Mexico Livestock Board have confirmed the state’s first case of equine herpes myeloencephalopathy (EHM), a serious neurologic disease linked to Equine Herpesvirus-1 (EHV-1). This announcement has prompted immediate preventive measures among horse owners statewide, as ranchers and equestrians take action to protect their animals.
In response to the confirmed case, the village of Corrales has canceled its annual Christmas de los Caballos All Equine Parade and Food and Toy Drive, originally scheduled for November 23, 2025. The affected horse, located in Doña Ana County, had recently attended the 2025 Women’s Professional Rodeo Association World Finals and Elite Barrel Race, which took place in Waco, Texas, from November 5-9. Currently, the horse is isolated and is improving under supportive veterinary care.
This confirmation comes as both the Texas Animal Health Commission and the Oklahoma Department of Agriculture, Food, and Forestry reported cases of EHM on November 18, 2025. These cases were associated with equine events that saw participants from multiple states, including New Mexico. EHV-1 is known to be a highly contagious virus that affects horses, donkeys, and mules, spreading through respiratory secretions, shared equipment, trailers, and contaminated environments.
While EHV-1 does not infect humans, it can cause severe health issues in horses, including respiratory illness, abortions, foal deaths, and the neurologic condition EHM. Symptoms of EHM may include fever, nasal discharge, cough, lethargy, hindlimb weakness, difficulty rising, loss of tail tone, urinary retention, and in severe cases, inability to stand.
Dr. Samantha Holeck, the state veterinarian, emphasized the importance of immediate isolation and veterinary evaluation. “Horse owners should closely monitor their animals and practice heightened biosecurity, especially if they recently attended events in Texas or Oklahoma,” Dr. Holeck stated.
Diagnosing EHV-1 involves PCR testing of nasal swabs and whole blood, providing the most accurate results. State officials stress that early testing and strict isolation of any horse displaying signs of illness are crucial to preventing further spread of this virus. Although there is no cure for EHV-1, most respiratory cases recover fully with supportive care, and mares affected by the reproductive form typically show improvement. Neurologic cases can vary significantly, with severe paralysis often resulting in a poorer prognosis.
To mitigate the risk of transmission, state officials have recommended several measures for horse owners, including:
1. Immediate isolation of any horse showing signs of illness.
2. Close monitoring of animals, especially those that have attended recent events.
3. Strict adherence to biosecurity practices.
Additional resources for horse owners are available from the New Mexico Livestock Board, the New Mexico Department of Agriculture, the American Association of Equine Practitioners, and the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service. For inquiries regarding EHV-1 testing, horse owners can contact the New Mexico Department of Agriculture’s Veterinary Diagnostic Services at 505-383-9299. For regulatory or livestock health concerns, the New Mexico Livestock Board can be reached at 505-841-6161. Horse owners are encouraged to consult their veterinarians for guidance on diagnosis, treatment, and vaccination options.
