11/21/2025
I wanted to give you a quick update on the Equine Herpesvirus Myeloencephalopathy (EHV-M) outbreak. The information coming out and about this outbreak is ever changing. First, I need to correct my previous information, the origin of the outbreak was in Waco Texas at the Women’s Professional Rodeo Association (WPRA) World Finals and Elite Barrel Race event Nov 5-9.We do now have any confirmed two confirmed case of EHV in Larimer County. The positive case has the respiratory version of EHV-1 and attended the event in Waco Tx. There is now a report of a second case of EHV of the neurological strain. On the EDCC website it lists it as a different case, although from what I can read into this, this horse is the same horse that had the initial positive test results of EHV respiratory strain. The respiratory strain can mutate into the neurological strain. Horse Owners: If your horses traveled to Texas or other equine events where EHV exposure may have occurred contact me. Exposed horses should be isolated for 21 days after last known exposure. Appropriate isolation includes restricted access to other horses, avoiding the sharing of equipment or personnel, and utilization of protective barrier precautions. Exposed horses should be monitored twice daily for elevated temperature (above 101.5*), respiratory signs (nasal discharge, coughing), and for clinical signs consistent with equine herpes myeloenceophalopathy (neurologic symptoms including inability to stand, difficulty walking, lethargy, and urine dribbling). Maintain a log with temperatures and clinical signs. If elevated temperature, respiratory signs, or EHM-compatible clinical signs are noticed, contact your veterinarian. Unless you have travelled to or know of any horses at your barn that travelled to the event Texas in the past couple of weeks, you should not worry. However out of an abundance of caution, I am recommended that all barns and boarding facilities limit the movement of horses on and off the premise for at least the next week or two. I have been asked about the vaccine. If you had your horse vaccinated this fall for "fall shots" and they received the Influenza/Rhinopneumonitis Prest, then your horse received the EHV1-4. Rhinopneumonitis is another way of phrasing EHV. If your horse has not received the Influenza/Rhinopneumonitis vaccine in the last 6 months, then it might be something to consider. An excellent resource for following any and all horse disease outbreaks in the US is Equine Disease Communication Center https://equinediseasecc.org/alerts Another link within this website is: For accurate and reliable information regarding the clinical signs and transmission of EHV-1, visit the EDCC: https://www.equinediseasecc.org/equine-herpesvirus I am trying to give you all the information I have at the current moment. Please be patient with my responses back to in about individual questions you might have, I am being inundated with questions.
Equine herpesvirus (EHV) is a family of equine viruses named by numbers including EHV-1, 2, 3, 4 and 5 with EHV-1,3,4 posing the most risk for domestic horses. EHV is a common DNA virus that occurs in horse populations worldwide. The two most common species are EHV-1 and EHV-4.
