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Click the link below to see a map of current quarantines and hold orders due to EHV.

Quarantine County Map

ALBUQUERQUE, N.M. – The New Mexico Department of Agriculture (NMDA) and the New Mexico Livestock Board (NMLB) are urging horse owners to take immediate preventive measures following confirmation of the state’s first case of equine herpes myeloencephalopathy (EHM), the neurologic disease associated with Equine Herpesvirus-1 (EHV-1).

The affected horse, located in Doña Ana County, attended the 2025 WPRA World Finals and Elite Barrel Race in Waco, Texas, held Nov. 5-9. The animal is currently isolated from other horses and is improving with supportive veterinary care.

This confirmation comes as the Texas Animal Health Commission and the Oklahoma Department of Agriculture, Food, and Forestry announced confirmed EHM cases in their respective states on Nov. 18, following equine events attended by horses from multiple states, including New Mexico.

EHV-1 is a common, highly contagious virus that affects horses, donkeys and mules. It spreads through respiratory secretions, shared equipment, trailers and contaminated environments. While it cannot infect humans, the virus can cause respiratory illness, abortions, foal death and the serious neurologic condition EHM. Symptoms may include fever, nasal discharge, cough, lethargy, hindlimb weakness, difficulty rising, loss of tail tone, urinary retention and—in severe cases—inability to stand.

“Immediate isolation and veterinary evaluation are the most effective tools we have,” said state veterinarian Dr. Samantha Holeck. “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 PCR testing of nasal swabs and whole blood, which provides the most accurate results. State officials emphasize that early testing and strict isolation of any horse showing signs of illness are critical to preventing further spread.

Although there is no cure, most respiratory cases recover fully with supportive care, and mares affected by the reproductive form typically improve. Neurologic cases vary widely, with severe paralysis carrying a poorer prognosis.

To reduce risk, state officials recommend that horse owners:

  • Follow veterinary vaccination guidance
  • Isolate new horses for 2-3 weeks before introducing them to the herd
  • Avoid sharing equipment such as halters, buckets and grooming tools
  • Disinfect barns and tack regularly
  • Monitor horse temperatures daily during high-risk periods
  • Limit horse movement during regional or local outbreaks

Additional resources are available from the New Mexico Livestock Board, the American Association of Equine Practitioners and the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service.

For questions about EHV-1 testing, contact NMDA’s Veterinary Diagnostic Services at 505-383-9299. For regulatory or livestock health concerns, contact the New Mexico Livestock Board at 505-841-6161. Horse owners should consult their veterinarians for guidance on diagnosis, treatment and vaccination.

See PDF version of this at the link below:

EHV1 first case_2025_English.pdf

UPDATED Equine Entry Requirements:

Due to the current Equine Herpes Virus (EHV-1) multi-state outbreak, New Mexico is instituting the following action.  Effective immediately, interstate certificates of veterinary inspection (ICVIs) for equids originating from states with confirmed positive EHV-1 cases will need to be issued within 5 days of travel.  Temperature MUST be recorded on the ICVI.  The following statement must be included: “Within the last 21 days, the equids listed on this CVI have not originated from a premises currently quarantined for EHV-1, have not been exposed to EHV-1, and have not attended an event where EHV-1 has been confirmed.”  Failure to comply with these requirements may result in regulatory or legal action.

Please be aware that many states are changing their entry requirements for equids.  You will need to contact the state of destination for the most current requirements.

For Printable Version Click here

The Texas Animal Health Commission (TAHC) and Oklahoma Department of Agriculture, Food, and Forestry have confirmed equine herpes myeloencephalopathy (EHM), the neurologic disease linked to equine herpes virus (EHV-1), in their respective states on November 18, 2025.

The horses in Texas attended the 2025 WPRA World Finals and Elite Barrel Race event in Waco, TX on November 5-9, 2025. The horses in Oklahoma attended the Barrel Futurities of America event in Guthrie, OK on November 17-18, 2025, before the remainder of the event was canceled.  TAHC and ODAFF staff are working closely with event coordinators, equine owners, and other states to respond to the outbreak, and take measures to protect horses and prevent the further spread of the virus.

Unfortunately, these events were attended by horses from many states, including New Mexico. Owners of horses that may have been in contact with these horses or exposed to EHM should work with their veterinarian to establish appropriate biosecurity and monitoring plans such as:

• Isolating the horses that attended the event for at least two weeks.

• Having the temperature of returning horses monitored twice daily for at least 14 days after last known exposure. Fever greater than 101.5 F is often the first indicator of EHV-1.

If a fever (>102.5°F) or other signs consistent with EHM develop, contact your veterinarian.

Clinical signs of EHM in horses may include:
Lethargy
Nasal discharge
Discharge from the eyes or nose
Swelling of the legs
Lack of coordination
Hindquarter weakness
Leaning or resting against a surface to maintain balance
>Urine dribbling
Diminished tail tone
Penile paralysis
Head tilt
Abortion in pregnant mares

It is important to remember these signs are not specific to EHM and diagnostic testing is required to confirm infection. If you suspect your horse has been exposed to EHV-1, contact your local veterinarian.

To avoid the spread:

  • Wash your hands and use hand sanitizer before and after working with a horse
  • Disinfect clothing and footwear before and after working with a horse
  • Wash and disinfect any items – feed/water buckets, grooming gear, saddles and other tack that horses have touched or might touch
  • Avoid walking through or visiting other barns or facilities with horses

Additional resources for equine owners can be found here:

The extent of this EHV-1 outbreak is not yet fully known. Presentation of EHV-1 in these horses has been acute with rapid progression and high clinical severity. A concerning number of mortalities in horses suspected of having EHM have been reported in other states and the need for rapid and proactive actions to curb the spread is clear. Measures to prevent contact of horses from exposure to the virus and increased biosecurity overall are recommended.

New Mexico has tracebacks to the following counties:
Dona Ana
Eddy
Santa Fe
De Baca
Roosevelt
Otero
Chaves

Given the nature of this virus and routes of transmission, the New Mexico Livestock Board Office of the State Veterinarian recommends canceling or postponing equine events to protect horses from further exposure until the extent of the current outbreak has been determined.

New World Screwworm larvae feed on living tissue of warm-blooded animals. They infest open wounds (or natural orifices), causing deep, painful lesions, infections, and potentially death if untreated. Though not yet present in New Mexico, vigilance is critical to preventing establishment.

WHAT TO WATCH FOR:

  • Open wounds that worsen or do not heal
  • Animals exhibiting restlessness, licking or biting at a wound, or isolating themselves
  • Visible maggots in wounds
  • Swelling, discharge, foul smell, or unusual tissue deterioration

To continue reading, click the link to the flyer provided by NMDA below:

NMDA New World Screw Worm Information Flyer