EHV-1 Outbreak Reported in Texas

Austin, Texas – Commissioner Sid Miller and the Texas Department of Agriculture (TDA) today issued an alert to Texas horsemen of an outbreak of Equine Herpesvirus Type 1 (EHV-1) reported by Texas veterinarians after the recent World Championship Barrel Racing (WPRA) Finals in the Waco area on November 5-9. Commissioner Miller is urging all horse owners, trainers, and venue operators who attended or were in proximity to the event, or who have recently returned from any large equine gathering in the Waco region in the last 14 days to act swiftly, monitor their animals carefully, and implement heightened biosecurity measures.

“This virus can spread fast, it can be deadly, and the earliest signs are often so subtle they’re easy to miss,” Commissioner Miller, himself an avid horseman, said. “That’s why monitoring your horses right now is critical. The quicker we identify a potential case, the better chance we have to protect not only our animals, but the entire Texas equine community.”

A particularly aggressive strain of EHV-1 has been confirmed by veterinary clinics in Central Texas. While investigations are ongoing, the TDA believes the situation warrants immediate attention, given the rapid spread and severe outcomes in affected horses.

Those who should act immediately are those who:

• Have a horse that was present at the WPRA event in the Waco area or transported one to/from that event.
• Have a horse that has mingled with those transported from that event.
• Any horse owner or facility operator who has recently participated in large multi–barn gatherings, roping jackpots, or traveled extensively enough to include the Waco region.

Clinical signs of EHV-1 can vary widely, and may include:

• Fever
• Nasal discharge, coughing, or other respiratory changes
• Depression or lethargy.
• Neurological signs: stumbling or incoordination, loss of tail tone, hind-limb weakness, head tilt, recumbency.
• Abortions in pregnant mares.

The EHV-1 virus spreads quickly and efficiently, making early precautions essential. Horses can transmit the virus directly through simple nose-to-nose contact, and infected animals may also release contagious aerosolized particles when they cough or sneeze. Indirect transmission is equally dangerous, as shared tack, grooming tools, water and feed buckets, thermometers, and other equipment can all carry the virus from one horse to another. Even humans can unintentionally act as mechanical carriers, spreading the virus on their hands, clothing, or boots.

To protect your horses and the broader equine community, the TDA recommends the following immediate steps:

1. Isolate any horse that attended the Waco event for at least 14 days from other equines, or until cleared by a veterinarian.
2. Suspend hauling, showing, or mixing horses from the exposure group until further notice. Avoid taking exposed horses to other barns or events.
3. Disinfect trailers, wash-racks, cross-ties, tie-areas, tack rooms, buckets, grooming tools, and any shared equipment. Use an appropriate virucidal disinfectant.
4. Avoid sharing tack, halters, grooming equipment, buckets, water hoses, etc., between exposed and unexposed horses.
5. Monitor temperatures twice daily for all exposed horses and report any fever (≥101.5 °F) or other signs to a veterinarian immediately.
6. If any horse exhibits neurologic signs, coughing, or nasal discharge, isolate it immediately, wear protective gear, and call your veterinarian.
7. Keep accurate records: track which horses were present at events, their movement, and who handled them for contact tracing if needed.
8. Stay in contact with your local veterinarian and keep up to date on updates from state veterinary authorities.

“I’m asking every local horse rider, roper, trainer, and breeder to do their part today,” Commissioner Miller added. “Check your horses twice a day, isolate any exposed animals, tighten up your biosecurity, and call your vet the moment something looks off. If we work together and take this seriously, we can get ahead of this outbreak and keep our horses and our state’s $12.3 billion equine industry safe.”

What is Equine Herpes Virus?

The horse can be affected by many different strains of equine herpes virus (EHV), also known as rhinopneumonitis, but five strains are most prevalent: EHV-1, EHV-2, EHV-3, EHV-4, and EHV-5. Of these, EHV-1 and EHV-4 are associated with viral respiratory disease, with EHV-4 mostly affecting young horses younger than 3 years of age. EHV-1 is the most prevalent concern in horse populations of all ages, not only because its respiratory disease is more virulent than that of EHV-4, but also because it can cause viral abortion in pregnant mares or neurologic disease (equine herpes myeloencephalopathy or EHM). Mutation of the DNA in the herpes virus produces this extremely virulent neurological form, which damages blood vessels in the central nervous system. Subsequent damage to the spinal cord tissues and brain is accompanied by specific neurological signs.

How EHV-1 Works

Horses often contract the herpes virus at a young age but do not always develop apparent clinical signs at that time. Like herpes infections in humans, the virus often goes dormant but can resurface when the horse is stressed by training, transport, competition, herd dynamics, or other health conditions.

Re-activation of the latent virus results in active shedding of the virus in the horse’s nasal secretions. Even a healthy-looking horse can transmit the EHV-1 virus from his respiratory secretions. Horses with clinical signs shed viral particles profusely and should be isolated immediately.

Direct horse-to-horse contact facilitates exposure, but the virus can also be transmitted on peoples’ hands, clothing and shoes, as well as grooming equipment, tack, buckets, rakes, hoses and water tanks, to name a few. It is also possible for airborne particles expelled by coughing or sneezing to transfer to horses some distance away, although no one knows exactly how far.

— Edited Press Release | Source: Texas Department of Agriculture