Four horses have been confirmed positive for EHV-1 after attending a large barrel racing competition in Waco, Texas in November 2025. Credit: AdobeStock
Amanda Masholie, Sustainable Ag & Small Farms Agent, UF/ IFAS Walton County Extension, Jennifer Bearden, Agriculture Agent, UF/ IFAS Okaloosa County Extension, Kaylan M. Waters, Agriculture Agent, UF/ IFAS Holmes County Extension, Dr. Sally De Notta DVM, DACVIM, University of Florida College of Veterinary Medicine, and Dr. Carissa Wickens, Associate Professor, Extension Equine Specialist, University of Florida
Recently, an EHV-1 outbreak occurred with four horses confirmed positive (more expected) that participated in the World Championship Barrel Racing (WPRA) Finals, near Waco, Texas, in early November. Active cases of EHV-1 have also been reported in Texas, Oklahoma, Louisiana, and Colorado. As of November 19, no cases of EHV-1, associated with this outbreak, have been identified in Florida.
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What is EHV-1?
EHV stands for Equine Herpes Virus. EHV-1 is very common. In fact, most adult horses have been infected with this virus with no serious consequences. Once infected, horses can become carriers of this latent virus. The virus can become active again when animals experience stress, such as during travel and exercise. It is estimated that about 60% of horses are carriers of EHV-1.
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What are the different forms of EHV-1 and their symptoms?
EHV-1 can be seen in many forms – neurological, respiratory, or abortion. Neurological symptoms include fever, stumbling, weakness, inability to stand, head tilting, and uncontrolled urination. Respiratory symptoms include fever, nasal discharge, cough, loss of appetite, and lethargy. If a mare aborts, she may have a fever but can show no symptoms at all. The incubation period can range from two to ten days before clinical signs develop.
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How is EVH-1 Transmitted?
Transmission occurs when infected and uninfected animals come in either direct (nose to nose) or indirect (through contaminated surfaces like tack, stalls, feeders, buckets, human handlers, etc.) contact with the nasal discharges of an infected animal. The virus can be transmitted in the air for short distances and by contact with aborted fetuses, placental fluids, or placentas from infected animals.
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What can a horse owner do to protect against infection?
Keep all equine vaccinations current. Although, there is no vaccine that provides protection from the neurological form, keeping your horse healthy will help their immune system fight off infections. Vaccination with EHV vaccines can provide protection for respiratory disease and abortion. Veterinary-client relationships are always highly encouraged. Consult with your veterinarian regarding a thorough vaccination protocol.
Limit hauling and exposure, especially to areas with active cases. All horse owners with horses in or traveling from affected regions should vigilantly monitor horse health conditions following this outbreak.
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Recommended biosecurity measures to consider:
- Check temperatures daily, before hauling, and watch for any abnormal behavior.
– - Do not travel to infected regions unless it is unavoidable.
– - Do not travel with any horse that exhibits signs of illness.
– - Avoid sharing buckets, hoses, grooming tools or tack.
– - Eliminate nose to nose contact between horses from different barns or trailers.
– - Keep stalls and tie-out areas clean.
– - If traveling and stalling horses overnight, consider having additional spacing between stalls to limit contact with horses from other barns or areas.
– - Disinfect all high contact areas with bleach including stall areas when traveling with your horse.
– - If your animal has been exposed to EHV-1 it is extremely important to quarantine your horse for a minimum of 21 days from the rest of your home herd.
– - Quarantine any new equines that come to your farm to avoid spreading any unwanted disease.
– - Encourage on-farm biosecurity measures like wash stations, boot disinfectant vats, hand sanitation, tool sanitation, and additional practices for human handlers (farriers, exercise riders, trainers, owners, veterinarians, feed delivery and service workers, etc.) that visit other horse farms. Encourage personal hygiene to ensure that hands, boots, clothing, and tools are free from the virus before handling horses.
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Biosecurity measures are always good practice. Don’t share water or feed buckets with other horses. Avoid nose to nose contact between horses at shows, trail rides, and other events. Clothes, trailers, tack and grooming equipment also should be disinfected as they can spread diseases as well. If you suspect your horse may have EHV-1, contact your veterinarian immediately.
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FDAC Published Protocol:
The Florida Department of Agriculture & Consumer Service is requesting that if your horse or horses have traveled to Texas or any infected area in the last two weeks, please keep your animals quarantined for 21 days. Additional movement requirements or restrictions have not been imposed by the State of Florida. However, other states or equine venues may enact additional movement requirements. Horse owners, trainers and veterinarians are advised to contact the state and venue of destination for any additional movement requirements prior to travel. In addition, Florida equine events are encouraged to implement enhanced biosecurity measures.
We are asking all those in the equine community to practice prudent biosecurity on their farm and to report any suspected EHV-1 neurological cases. For reporting, call (850) 410-0900 Monday through Friday 8:00 a.m. – 5:00 p.m. and 1-800-342-5869 after hours and weekends or email RAD@FDACS.gov. Please continue to visit the FDACS Animal Industry website for current information regarding disease outbreaks in Florida.
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More information on the recent Outbreak of EHV-1:
Texas press release
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Equine Disease Communication Center (EDCC) update
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EDCC Info about EHV: To learn more about EHM, including signs, diagnosis, treatment, and prevention
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Florida Department of Agriculture: Equine Herpesvirus-1
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U.S. Animal health Association Equine Herpesvirus Myeloencephalopathy Incident Guidelines
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Interstate Movement Requirements:
www.InterstateLivestock.com
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www.Animalregs.com
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American Association of Equine Practitioners:
Equine Vaccination Guidelines for Infectious Disease Control
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Infectious Neurologic Disease Field Diagnostic Guidelines
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Manifestations of Equine Herpesvirus-1, University of Kentucky
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USDA Equine Herpesvirus
As the Sustainable Ag and Small Farms Extension Agent in Walton County, I support the food and fiber system by specializing in the following areas: small homesteads, animal science, farm planning, farm management, beginning farmer, direct marketing and soil health.
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