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 neurological disease linked to Equine Herpesvirus-1 (EHV-1). This development has prompted a call for immediate preventive measures among horse owners across the state.
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, which took place from November 5 to 9. Following the announcement, the village of Corrales has canceled its annual Christmas de los Caballos All Equine Parade and Food and Toy Drive scheduled for November 23. The horse is currently isolated and is reportedly improving under supportive veterinary care.
As part of a broader response, the Texas Animal Health Commission and the Oklahoma Department of Agriculture, Food, and Forestry also confirmed EHM cases in their jurisdictions on November 18. These cases followed equine events attended by horses from multiple states, including New Mexico.
EHV-1 is a highly contagious virus that affects horses, donkeys, and mules. It spreads through respiratory secretions, shared equipment, and contaminated environments. While it does not infect humans, it can lead to respiratory illnesses, abortions, foal fatalities, and the neurologic condition EHM in horses. Symptoms of EHM may include fever, nasal discharge, cough, lethargy, hind limb weakness, difficulty rising, loss of tail tone, urinary retention, and in severe cases, the inability to stand.
Dr. Samantha Holeck, the state veterinarian, emphasized the importance of swift action: “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.”
Diagnosis of EHV-1 is conducted through 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 showing signs of illness are critical in preventing further spread of the virus.
Although there is currently no cure for EHV-1, most respiratory cases recover fully with appropriate supportive care, while mares affected by the reproductive form typically improve. Neurologic cases, however, vary significantly in severity, with severe paralysis leading to a poorer prognosis.
To mitigate risks, state officials recommend that horse owners implement specific preventive measures. Resources on EHV-1 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 inquiries about EHV-1 testing, horse owners can contact NMDA’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. It is crucial for horse owners to consult their veterinarians for guidance on diagnosis, treatment, and vaccination.
