Dr. Erika M. Johnson, DVM

11/22/2025

𝐄𝐇𝐕-𝟏 𝐚𝐧𝐝 𝐄𝐇𝐌 𝐒𝐞𝐫𝐢𝐞𝐬: 𝐂𝐮𝐫𝐫𝐞𝐧𝐭 𝐭𝐫𝐚𝐧𝐬𝐩𝐨𝐫𝐭 𝐫𝐞𝐜𝐨𝐦𝐦𝐞𝐧𝐝𝐚𝐭𝐢𝐨𝐧𝐬 𝐚𝐧𝐝 𝐫𝐞𝐪𝐮𝐢𝐫𝐞𝐦𝐞𝐧𝐭𝐬

The initial outbreak of EHV-1 with an EHM (Equine Herpes Myeloencephalopathy) form occurred after a Women’s Professional Rodeo Association (WPRA) World Finals event in Waco, TX (Nov. 5-9). After this event, many of the same horses attended other events in TX and OK before experiencing any clinical signs (average of 4-7 day incubation period), which is what contributed to the multi-state spread of this disease. After the BFA event in Guthrie, OK was cancelled, owners were advised to leave the premises, bringing potentially exposed horses back to their home states and is another reason why we are seeing the disease in so many areas now.

As of 12:00pm on 11/21/2025, there are 15 confirmed cases of EHM and 1 confirmed case of EHV-1 without neurologic signs in the states of Texas, Oklahoma, Louisiana, Colorado and New Mexico. There is one unrelated case (not associated with this event/outbreak) reported in Maryland. There are many other horses undergoing testing without confirmed, reported numbers at this time.

So, what does this mean for current travel recommendations, health certificate requirements and upcoming events?

𝐀𝐫𝐢𝐳𝐨𝐧𝐚 & 𝐍𝐞𝐯𝐚𝐝𝐚 𝐃𝐞𝐩𝐚𝐫𝐭𝐦𝐞𝐧𝐭 𝐨𝐟 𝐀𝐠.: Horses that have been at the following locations will not be allowed entry into the state for 21 days following potential exposure even if they are not symptomatic if they have been on the following premises (subject to change):

- Extraco Events Center (Waco, TX)
- 377 Arena (Stephenville, TX)
- Lazy E Arena (Guthrie, OK)
- Jackson County (Edna, TX)

Health certificates for the horses traveling into these states will require a statement from the veterinarian filling out the health certificate stating that the horse has not been on one of these premises (or any that come up with an EHV-1/EHM positive case) for the 21 days leading up to the date of the health certificate.

𝐘𝐨𝐮𝐫 𝐭𝐲𝐩𝐢𝐜𝐚𝐥 𝟑𝟎 𝐝𝐚𝐲 𝐡𝐞𝐚𝐥𝐭𝐡 𝐜𝐞𝐫𝐭𝐢𝐟𝐢𝐜𝐚𝐭𝐞 𝐰𝐢𝐥𝐥 𝐧𝐨𝐰 𝐨𝐧𝐥𝐲 𝐛𝐞 𝐯𝐚𝐥𝐢𝐝 𝐟𝐨𝐫 𝟓 𝐝𝐚𝐲𝐬 𝐢𝐟 𝐭𝐡𝐞 𝐬𝐭𝐚𝐭𝐞 𝐲𝐨𝐮 𝐚𝐫𝐞 𝐭𝐫𝐚𝐯𝐞𝐥𝐢𝐧𝐠 𝐟𝐫𝐨𝐦 𝐡𝐚𝐬 𝐡𝐚𝐝 𝐚 𝐩𝐨𝐬𝐢𝐭𝐢𝐯𝐞 𝐜𝐚𝐬𝐞 𝐨𝐟 𝐄𝐇𝐕-𝟏/𝐄𝐇𝐌.

The National Finals Rodeo Committee released the following statement this morning in regards to the NFR event happening in December:
- “All horses must have a 7 day Certificate of Veterinary Inspection (CVI) and unique entry permit number obtained from the NV Dept. of Ag.
- All participants and competitors are responsible for daily temperature monitoring of their horses.
- There is a no-travel advisory for all horses participating and competing at the NFR.
- Enhanced verification and check-in procedures will be in place at the Thomas & Mack Center.
- Biosecurity measures will be maintained throughout the event.”

𝐓𝐡𝐞 𝐎𝐫𝐞𝐠𝐨𝐧 𝐃𝐞𝐩𝐚𝐫𝐭𝐦𝐞𝐧𝐭 𝐨𝐟 𝐀𝐠𝐫𝐢𝐜𝐮𝐥𝐭𝐮𝐫𝐞 (𝐎𝐃𝐀) has additionally released new rules to mitigate EHV risk. Exhibitions/events where other equines will be present need to register with the ODA at least 20 days prior to the event. Additionally, event organizers/producers need to have a record of all animals/competitors for 90 days following the event, which will only need to be made available to the ODA in the case of an outbreak. They recommend consulting with your licensed veterinarian on protocols to establish if a sick animal is discovered during the event, and a licensed veterinarian of record must be available to provide services during the event. If any animals show potential signs of infectious, contagious or communicable disease they will not be allowed entry to exhibitions/events, and should remain isolated until they are able to be examined by a veterinarian.

As this is an evolving situation, guidelines will likely continue to change. Please feel free to ask questions in the comments below.

Up to date information on reported positive cases can be found here: https://equinediseasecc.org/news/article/Equine-Herpesvirus-Myeloencephalopathy-(EHM)-Outbreak

Rules for the state of OR can be found here: https://www.oregon.gov/oda/animal-health-feeds-livestock-id/exhibitions/pages/exhibition-rules.aspx

-Dr. Cooper