Get the latest updates on the EHV-1/EHM outbreak linked to the WPRA World Finals. See affected states, symptoms, and essential biosecurity tips for horse owners.
Updated: 11/24/25 12:15 pm
An outbreak of Equine Herpesvirus-1 (EHV-1), including its severe neurologic form, Equine Herpesvirus Myeloencephalopathy (EHM), continues to spread following a major barrel racing event in Waco, Texas. The outbreak, linked to the WPRA World Finals and Elite Barrel Race held from Nov. 5-9, has now resulted in 28 confirmed cases across eight states as of Nov. 24. With cases spanning from the West Coast to the Gulf Coast, veterinary officials are urging horse owners to implement strict biosecurity for horse diseases to prevent further transmission.
This evolving situation highlights the critical need for vigilance within the equine community. Understanding the scope of the EHV-1 outbreak, recognizing symptoms, and following expert recommendations are essential for protecting equine health. This article provides the latest updates, outlines affected areas, and offers guidance for horse owners.
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EHV-1 Outbreak: Latest Case Counts and Affected Areas
The Equine Disease Communication Center (EDCC) has confirmed that the number of horses affected by the EHV-1/EHM outbreak has climbed to 28. The disease has spread significantly from the initial event location in Texas, impacting a wide geographic area.
States with Confirmed Cases:
- Texas
- Oklahoma
- Louisiana
- Colorado
- New Mexico
- Washington
- Arizona
- South Dakota
In Texas, the state where the originating event took place, several counties are now managing cases. The impacted counties include McLennan, Montgomery, Wharton, Bell, and Fort Bend. This broad distribution underscores how quickly the virus can travel as horses return home from competitions.
State-by-State Updates on EHM Cases in Horses
The severity of the outbreak is evident in the specific reports from state veterinary officials. While some horses show milder signs, others have developed the more dangerous neurologic form of the disease.
Texas
The situation in Texas has been particularly serious, with multiple counties reporting severe outcomes. In Montgomery County, one horse was euthanized after developing advanced EHM. A similar tragedy occurred in Bell County, where a horse became recumbent shortly after being hospitalized and was euthanized within 48 hours. These incidents underscore the rapid and severe nature of EHM.
Oklahoma
In Oklahoma, state officials have placed multiple exposed horses under quarantine. Some of these horses are already exhibiting neurologic signs consistent with EHM, prompting close monitoring by veterinarians.
Louisiana
The Louisiana State University (LSU) Veterinary Hospital is currently treating three horses that tested positive for EHM. These horses are receiving supportive care as veterinarians work to manage their neurologic symptoms.
Colorado
Colorado has confirmed one case of EHM in Larimer County. The affected horse is showing neurologic signs, and health officials are working to trace any potential secondary exposures.
New Mexico
New Mexico has also reported one confirmed EHM case. In addition to this case, other horses that were potentially exposed at the Waco event are being monitored under quarantine protocols.
South Dakota
South Dakota has reported one confirmed EHM case as of the morning of 11/24.
The Importance of EHV-1 Symptoms and Treatment
Recognizing the signs of EHV-1 is the first line of defense. The virus can present in several ways, from mild respiratory illness to the severe neurologic symptoms of EHM.
Common Symptoms of EHV-1:
- Fever (often the first sign)
- Nasal discharge
- Lethargy or depression
- Loss of appetite
Neurologic Signs of EHM:
- Incoordination or weakness, especially in the hind limbs
- Urine dribbling or inability to urinate
- Tail limpness
- Difficulty standing or rising (recumbency)
There is no cure for EHV-1, so treatment focuses on supportive care. This may include anti-inflammatory medications, intravenous fluids, and other measures to keep the horse comfortable and stable. For horses with EHM, slings may be used to help them stand. Early veterinary intervention is critical for improving the chances of a positive outcome.
Biosecurity Is the Key to Containment
Veterinary experts and organizations like the EDCC cannot overstate the importance of biosecurity. Preventing the spread of the virus is paramount during an active outbreak.
Key Biosecurity Measures:
- Isolate New and Traveling Horses: Any horse that has traveled to an event, especially one linked to an outbreak, should be isolated for at least 21 days. This includes preventing nose-to-nose contact and using separate equipment.
- Monitor for Symptoms: Check your horse’s temperature twice daily. A fever is often the earliest indicator of infection.
- Practice Strict Hygiene: Wash your hands and change clothes and footwear between handling different groups of horses. Disinfect stalls, trailers, and any shared equipment like water buckets, feed tubs, and grooming tools.
- Limit Horse Movement: Avoid non-essential travel with your horses until the outbreak is under control. This helps reduce the risk of introducing the virus to new facilities.
- Consult Your Veterinarian: If you suspect your horse has been exposed or is showing symptoms, contact your veterinarian immediately. They can provide guidance on testing, treatment, and quarantine protocols.
What to Know Moving Forward
While the EHV-1/EHM outbreak linked to the WPRA World Finals is a serious concern, it is important to remember that a majority of horses recover. According to the EDCC, approximately 60-70% of horses affected by EHM recover with proper supportive care. However, the potential for severe illness and the highly contagious nature of the virus demand a cautious and proactive response from the entire equine industry.
Horse owners are encouraged to stay informed through reliable sources like the EDCC and their state veterinarian's office. By working together and adhering to strict biosecurity protocols, the community can help contain this outbreak and protect the health and welfare of all horses.
Continue to track the evolving outbreak through EDCC's website here.
