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 the Equine Herpesvirus-1 (EHV-1). Horse owners are being urged to implement immediate preventive measures to safeguard their animals following this alarming development.
The affected horse, located in Doña Ana County, attended the 2025 Women’s Professional Rodeo Association World Finals and Elite Barrel Race in Waco, Texas, from November 5 to 9. Currently, the horse is isolated and receiving supportive veterinary care, showing signs of improvement. The announcement has prompted swift actions across the state, including the cancellation of the annual Christmas de los Caballos All Equine Parade and Food and Toy Drive in the village of Corrales, originally scheduled for November 23.
This confirmation follows reports from both the Texas Animal Health Commission and the Oklahoma Department of Agriculture, Food, and Forestry, which announced their own confirmed EHM cases on November 18. These cases emerged after equine events that involved horses from multiple states, including New Mexico. EHV-1 is a highly contagious virus that primarily affects horses, donkeys, and mules. It spreads through respiratory secretions, shared equipment, trailers, and contaminated environments, posing significant risks to equine populations.
EHV-1 does not infect humans, but it can lead to severe complications in horses, including respiratory illness, abortions, and, critically, the neurologic condition EHM. Symptoms of EHM may include fever, nasal discharge, cough, lethargy, and in severe cases, difficulty rising or even paralysis. According to Dr. Samantha Holeck, the state veterinarian, “Immediate isolation and veterinary evaluation are the most effective tools we have. Horse owners should closely monitor their animals and practice heightened biosecurity, especially if they recently attended events in Texas or Oklahoma.”
Veterinarians diagnose EHV-1 through polymerase chain reaction (PCR) testing of nasal swabs and whole blood, which is considered the most accurate method. State officials emphasize that early testing and strict isolation of any horse showing signs of illness are crucial steps in curbing further spread of the virus. While there is no definitive cure for EHV-1, many respiratory cases respond well to supportive care. In contrast, neurologic cases can vary significantly in severity, with more severe paralysis often resulting in a poorer prognosis.
To mitigate the risk of transmission, state officials recommend that horse owners adhere to several guidelines. These include monitoring their animals for any signs of illness, maintaining high standards of biosecurity, and ensuring that horses do not come into contact with others that might be infected.
Additional resources can be accessed through 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 questions regarding EHV-1 testing, horse owners are encouraged to 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 should consult their veterinarians for guidance on diagnosis, treatment, and vaccination options related to this serious health concern.
