11/24/2025
Navajo Nation update on the EVH-1 Outbreak 🐴
EHV stands for equine herpes virus, Equine herpesvirus myeloencephalopathy (EHM) is another name for the neurologic disease associated with equine herpesvirus (EHV) infections.
EHV-1 signs/symptoms:
Neurological signs, which are more severe, include hind limb weakness, incoordination, stumbling, loss of tail tone, difficulty urinating, and inability to rise.
Pregnant mares may abort, and newborn foals can die.
Respiratory signs are Fever (>101.5), Lethargy or depression, Reduced appetite,Cough, Nasal discharge (clear to thick yellow), and Enlarged lymph nodes.
EHV-1 is highly contagious and spreads primarily through direct horse-to-horse contact via respiratory secretions, aerosolized droplets, and indirect contact with contaminated equipment, water buckets, feed, tack, or human hands/clothing. Humans do not become ill from EHV-1 but can mechanically transmit the virus between horses.
Strict biosecurity remains the most effective means of preventing introduction and spread. Key measures include:
Disinfection of all shared equipment and surfaces with appropriate virucidal products. Limiting unnecessary horse movement, especially for animals with recent travel history to affected areas.
Implementing isolation protocols for any new or returning horses.
The Navajo Nation Veterinary Program and Navajo Nation Department of Agriculture will closely monitor AZ, NM, CO, and UT State Veterinarian restrictions and guidance.
If you have any questions or concerns please do not hesitate to call the Navajo Nation Veterinary Program at (505) 397-5355, thank you!