Important Equine Health Update: EHV-1 Outbreak in Texas & Oklahoma

From IA Equine

Dear Clients,

We hope you and your horses are doing well. We are reaching out with an important update regarding a recent outbreak of Equine Herpesvirus Type 1 (EHV-1) affecting horses in Texas and Oklahoma. While this outbreak is not in our immediate area, it’s important to stay informed and take precautions. In this email, we will explain what EHV-1 is, how it spreads, the difference between its respiratory and neurologic forms, what is known about the current situation, and steps you can take to protect your horses.

What is EHV-1 and How Does It Spread?

EHV-1 is a highly contagious virus that affects horses worldwide, known for causing respiratory illness, fever, and sometimes abortion in pregnant mares. In more serious cases, it can also cause a neurological disease (described below). The virus spreads very easily through close contact and shared environments. This includes nose-to-nose contact, droplets from coughing or sneezing, and shared equipment like water buckets, feed tubs, tack, or grooming tools. Humans can inadvertently carry the virus on their hands, clothing, or boots and spread it between horses. In some instances, horses can carry EHV-1 without showing signs and then shed the virus when they are stressed (for example, after travel or competition). Good hygiene and biosecurity are therefore essential to stop the virus from moving between horses.

Respiratory vs. Neurologic Forms of EHV-1 (EHM)

EHV-1 can cause illness in two main forms, which can be thought of as the respiratory form and the neurologic form:

• Respiratory Form: Often called equine rhinopneumonitis, this form looks similar to a flu or cold in horses. It usually causes fever, runny nose, cough, and lethargy. Most adult horses recover from the respiratory form with supportive care.

• Neurologic Form (EHM): In some cases, EHV-1 affects the horse’s nervous system; this severe form is known as Equine Herpes Myeloencephalopathy (EHM). Horses with EHM may show stumbling or incoordination, hind-end weakness, difficulty balancing or standing, difficulty urinating, loss of tail tone, or even paralysis. These neurological signs can appear suddenly and be very serious. EHM is often life-threatening and requires immediate veterinary care.

What We Know About the Texas/Oklahoma Outbreak

In early November 2025, a major barrel racing event in Waco, Texas was identified as the starting point of an EHV-1 outbreak. A particularly aggressive strain of the virus was confirmed in multiple horses that attended the event. Several of those horses became ill, and some developed neurological symptoms. There have been reports that a few horses have deteriorated rapidly or even passed away due to this outbreak.

Following the Waco event, some horses traveled to a barrel racing competition in Guthrie, Oklahoma. Partway through that event, a horse fell ill and tested positive for EHV-1, leading organizers to cancel the remainder of the show as a precaution. As of now, at least two cases have been confirmed in Oklahoma, and those horses had links to the Texas event.

State animal health officials in Texas and Oklahoma have responded swiftly. They have issued alerts urging anyone who attended these events (or had contact with horses that did) to immediately isolate those horses and monitor them closely. The situation is evolving, but there is no indication at this time that this outbreak has spread to Iowa. We are monitoring the news through veterinary networks and will keep you updated if that changes.

Important: EHV-1 is not contagious to people — it only affects equines. Humans cannot catch this virus, but we can carry it on our hands or equipment, so we still must be cautious.

How to Protect Your Horses

Even though this outbreak is centered in TX/OK, it’s a good reminder for all horse owners to practice vigilant biosecurity. Here are practical steps we strongly recommend to keep your horses safe:

• Practice Good Biosecurity: Prevent direct contact between your horse and others. Avoid all nose-to-nose touching with unfamiliar horses. Do not share water buckets, feed tubs, halters, lead ropes, bits, grooming tools, or any tack. Thoroughly disinfect barns, stalls, trailers, and equipment on a routine basis. Wash your hands after handling any horse that isn’t from your own barn, and consider changing clothes and cleaning boots if you’ve been around other horses.

• Monitor Your Horse’s Health: Take your horse’s temperature twice daily. A normal horse temperature is around 99–100°F; if you detect a fever of 101.5°F or above, consider it a red flag. Watch for any signs of illness: nasal discharge, coughing, lack of appetite, or depression. Be especially alert for neurological signs like stumbling, unsteady gait, hind limb weakness, or unusual behavior. If you observe a fever or any of these symptoms, isolate that horse and call us immediately.

• Isolate New or Exposed Horses: If your horse recently traveled to a show or clinic, or has been around horses that did, keep that horse separated from others for at least 14 days. Ideally, use a separate quarantine area at least 30 feet away from other horses. Use dedicated equipment and avoid rotating staff without proper disinfection.

• Limit Travel and Shows: If possible, consider postponing non-essential travel for the next few weeks. If you must attend a horse event, use caution: bring your own water, avoid communal water troughs, disinfect gear after returning, and minimize contact with other horses.

• Stay Informed and Prepared: Keep up with reliable information and ensure your horse’s EHV-1 (rhino) vaccination is up to date. While the vaccine cannot fully prevent infection or EHM, it can reduce the severity and amount of virus shed. Overall herd health, good nutrition, and reducing stress also help strengthen immunity.

  
  

Moving Forward Calmly and Carefully

We understand that news of a disease outbreak can be unsettling. EHV-1 is a serious virus, but by staying vigilant and following the precautions above, you can significantly reduce the risk to your horses. The majority of exposed horses do not develop severe complications. Our goal is to help you prevent problems and catch any signs early.

Please know that our veterinary team is closely monitoring this situation. We will keep you updated if there are any important changes. In the meantime, don’t hesitate to reach out with questions or concerns. We’re here to support you and your horses.

Warmly,

Iowa Equine Veterinary Team

More information can be found at https://www.equinediseasecc.org/equine-herpesvirus.