A highly aggressive strain of Equine Herpesvirus (EHV) has been confirmed by three leading equine veterinary clinics in Texas, with cases linked to a recent event in Waco as of November 18, 2025. This outbreak raises significant concern among horse owners, prompting recommendations to monitor at-risk horses and mitigate the spread of the disease.
Equine herpesvirus, often abbreviated as EHV, encompasses a group of highly contagious viruses impacting horses globally. Out of the nine identified strains, EHV-1, EHV-3, and EHV-4 present the most considerable health risks in the United States. While these viruses can cause severe illness in equines, they do not pose a risk to human health.
EHV-1 is the most alarming strain due to its potential to cause upper respiratory diseases and complications such as abortion or stillbirth in pregnant mares. It can also evolve into equine herpes myeloencephalopathy (EHM), a neurological condition that can be fatal. EHV-3 leads to coital exanthema, a venereal illness transmitted during breeding, while EHV-4 typically affects foals, causing respiratory disease and potential abortion in mares. Although most horses recover from EHV without lasting effects, neurological complications can complicate recovery.
Symptoms of EHV can vary significantly; some horses may not exhibit any signs, while others may develop severe illness. Common indications of infection include fever, nasal discharge, coughing, lethargy, urination difficulties, hind-limb weakness, stumbling, and, in the case of pregnant mares, abortion. As early symptoms can be subtle, it is crucial for horse owners to monitor their horses’ temperatures twice daily, particularly for those who attended equestrian events in Waco or similar gatherings in the past two weeks. A rectal temperature of 101.5°F or higher, especially alongside other symptoms, warrants immediate veterinary consultation.
EHV-1 spreads effectively through several mechanisms, including direct horse-to-horse contact, aerosolized particles from coughing or sneezing, shared or contaminated equipment, and even human transmission via hands or clothing. Additionally, infected mares can transmit EHV-1 to their foals, raising the stakes for maintaining vigilance within affected populations.
An additional challenge is that EHV-1 can remain latent in horses, who may not show any symptoms while still being able to shed the virus under stress. This aspect complicates efforts to control outbreaks as carriers may unwittingly contribute to the spread of the virus.
As the equine community navigates this critical situation, horse owners are encouraged to stay informed and vigilant to protect their animals. The Team Roping Journal continues to monitor developments and will provide updates as more official information becomes available. Our thoughts remain with those affected by this outbreak, highlighting the importance of community awareness and prompt action as integral parts of mitigating this health crisis.