11/19/2025
EHV Outbreak in Texas
While we have not seen any cases of EHV-1 or EHM at Comanche Creek Veterinary Services in Mason, Texas - more cases are very likely to develop in the coming weeks. Please be educated and advised about how to best protect your horses as this outbreak evolves.
Horses that spent any time at the WPRA finals in Waco, Texas or any large event since are likely at risk.
ENTRY REQUIREMENTS for large upcoming events may change.
Each state makes entry requirement rules for horses that we must follow when traveling. Events may also enforce their own set of rules to protect their participants.
________________________________________
What Horse Owners Should Do Right Now:
1. *Keep all horses at home!*
Please avoid hauling, clinics, lessons, shows, or mingling horses for the next several weeks until more information is available.
Movement is the #1 factor that spreads EHV-1.
________________________________________
2. Check temperatures twice daily!
Fever is usually the first sign (often before nasal discharge or neurologic symptoms).
• Temp at or above 101.5°F = call your veterinarian.
________________________________________
3. Notify your veterinarian immediately if your horse exhibits:
• Fever
• Weakness or incoordination
• Standing with hindlimbs wide
• Tail tone changes
• Difficulty urinating
• Lethargy or decreased appetite
Early intervention improves outcomes.
________________________________________
4. Biosecurity matters.
• Do not share water buckets, hoses, tack, grooming tools, or stalls.
• Disinfect trailers, thermometers, and crossties.
• Isolate any horse with fever immediately.
________________________________________
About Vaccination.
Current evidence shows vaccines do not prevent EHM, but they can reduce viral shedding and shorten viremia, which lowers barn-wide spread and is important to the community.
If never vaccinated for EHV (Typically given as a Flu/Rhino vaccine) it will take *TWO WEEKS* for a horse to develop protective immunity
Boosters are helpful when:
• A horse was vaccinated > 90 days ago, or
• You are preparing for high-risk environments (events, hauling, mixing populations).
What the research shows:
• Booster vaccination increases IgG1 and IgG4/7, the antibody classes linked with limiting viremia.
• Reduced viremia = reduced likelihood of severe disease and decreased transmission.
• Boosters are most effective in younger horses, previously vaccinated horses, and non-pregnant horses.
Vaccines do NOT stop a horse already incubating EHV-1 from developing signs, and they do not eliminate the risk of neurologic disease. For horses already exposed or febrile, do not vaccinate until cleared by your veterinarian.
________________________________________
Link to AAEP EHV guideline: https://aaep.org/resource/equine-herpesvirus-rhinopneumonitis-vaccination-guidelines/