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Equine Herpesvirus Type 1 (EHV-1) Outbreak

November 20, 2025
News article

We are monitoring an outbreak of Equine Herpesvirus Type 1 (EHV-1), including Equine Herpesvirus Myeloencephalopathy (EHM), associated with equine events in Oklahoma and Texas.

LDAF is advising horse owners who have attended an equine event in Texas or Oklahoma, within the last 3 weeks, to contact their veterinarian, isolate their horses, and implement twice daily temperature monitoring under the guidance of their veterinarian.

If elevated temperature, respiratory signs, or EHM-compatible clinical signs are noticed, owners should contact their veterinarian.

EHV‐1 is spread from horse to horse through contact with nasal discharge or spread as aerosol droplets. The incubation period is typically 2–10 days, meaning a horse can appear normal while still shedding the virus and act as a carrier. Horses can also contract the virus by coming into contact with contaminated surfaces such as stalls, water, feed, tack, and transport vehicles. People can spread the virus from horse to horse by contaminated hands and clothing. It is important for owners to watch for signs and symptoms and practice biosecurity measures .

Additionally, the Equine Disease Communication Center has created a page to provide outbreak information. This page will be updated regularly and will provide links to more information. You can find it here: https://equinediseasecc.org/alerts?alertID=4722 .

Contact info

Jennifer Finley, Press Secretary