EHV-1 (Equine Herpesvirus) Outbreak: Horse Owners Urged to Use Caution

The Navajo Nation Department of Agriculture and the Navajo Nation Veterinary Program are urging horse owners to take precautions due to a multistate outbreak of Equine Herpesvirus-1 (EHV-1) and the neurologic form, Equine Herpes Myeloencephalopathy (EHM).

 

This outbreak has been linked to large equine events in Waco, Texas and Guthrie, Oklahoma in early November 2025. Horses from Arizona, New Mexico, Colorado, and Utah were exposed. A confirmed case has now been reported in Doña Ana County, New Mexico.

 

Because quarantines were not enforced at those events, horse owners across the region are being urged to use extreme caution.

 

What is EHV-1?

EHV-1 is a highly contagious virus that spreads easily between horses through direct horse-to-horse contact, coughing or nasal secretions, shared tack, trailers, stalls, feed and water buckets, and contaminated human hands, clothing, and footwear. Some horses infected with EHV-1 develop the neurologic form, EHM, which can cause serious and sometimes fatal complications.

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Signs of EHM may include:

• lethargy

• nasal discharge

• discharge from the eyes or nose

• swelling of the legs

• lack of coordination

• hind-end weakness

• leaning or resting against objects for balance

• urine dribbling

• diminished tail tone

• head tilt

• abortion in pregnant mares

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These signs are not specific to EHV-1 or EHM. Veterinary diagnostic testing is required to confirm infection.

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If You Suspect Exposure or See Symptoms

If your horse has attended a recent large equine event, had contact with horses from out of state, has a fever over 102.5°F, or is showing any neurologic signs, contact a veterinarian immediately. Do not transport your horse unless instructed by a veterinarian.

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Current Movement Restrictions

The Arizona State Veterinarian has issued temporary movement restrictions that are being followed on the Navajo Nation. Interstate Certificates of Veterinary Inspection (ICVI) are only valid for five days if the horse was housed in a state with EHV-1 exposure. Additional health statements are now required for transported horses. Extended Equine Health Certificates of Veterinary Inspection (EECV) are paused for 30 days. Horses traveling into or out of Arizona must meet updated state import requirements.

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How to Help Prevent the Spread

Wash hands and use sanitizer before and after handling horses. Disinfect clothing, footwear, tack, buckets, grooming tools, stalls, and trailers. Remove all organic material before disinfecting. Use a 1:10 bleach solution or an approved disinfectant. Avoid unnecessary travel between barns and facilities. Do not share equipment between horses. Monitor horse temperatures twice daily if exposure is possible.

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Vaccination Guidance

Vaccination remains important for horses with no known exposure. Vaccinating horses that may already be exposed is not recommended at this time. Always consult your veterinarian before vaccinating during an outbreak.

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Local Veterinary Contacts

Animal Haven Clinic (Farmington, NM): 505-325-8829
Farmington Veterinary Clinic: 505-325-7462
Aspen Veterinary Clinic (Flagstaff, AZ): 928-526-2423
Airport Animal Clinic (Grants, NM): 505-287-2763
Dr. Kamper – Alpaca Vet (Flagstaff, AZ): 928-699-1338
Dr. Adrienne Ruby (Dilkon, AZ): 928-521-6241
Dr. Abby Reidhead (Holbrook, AZ): 928-524-9928
Cedar Ridge Vet Hospital (Taylor, AZ): 928-536-4153
Rez Solutions (Navajo Nation): 928-730-8262
Desert View Mobile Veterinary: 928-283-6184

Navajo Nation Veterinary Program: 505-397-5355

 

Official Statement

The Navajo Nation Department of Agriculture and the Navajo Nation Veterinary Program are actively monitoring guidance from Arizona, New Mexico, Colorado, and Utah State Veterinarians. Due to the rapid spread and high clinical severity of EHV-1 and EHM, increased biosecurity measures are being strongly encouraged to protect horses across the region.