The Oregon Department of Agriculture (ODA) State Veterinarian’s Office has reported an outbreak of Equine Herpes Virus (EHV), specifically Equine Herpes Myeloencephalopathy (EHM), linked to barrel racing and rodeo events in Texas and Oklahoma. Several EHM cases have been confirmed in those states, with additional reports and equine deaths still under investigation.
As of now, there are no confirmed EHV or EHM cases in Oregon. The ODA is coordinating with authorities in the affected states and awaiting further information regarding any Oregon horses that may have been exposed at these events. If exposures involving Oregon horses are identified, the department will contact owners directly and issue quarantine orders as needed.
“This outbreak serves as a reminder of the potential disease risks associated with large commingling equine events. It underscores the importance of timely reporting of diseases and ensuring that movement requirements are followed, including veterinary inspection and health certificates prior to travel,” stated the ODA.
Horse owners whose animals have traveled to Texas, Oklahoma, or other potentially affected events are advised to consult their veterinarians for guidance on isolation and monitoring procedures. Exposed horses should be isolated for 21 days after their last known exposure. Proper isolation includes restricting access from other horses, not sharing equipment or personnel, and using protective barriers. Owners should monitor exposed horses twice daily for elevated temperatures above 101.5°F, respiratory symptoms such as nasal discharge or coughing, and neurological signs like difficulty standing or walking.
If any such symptoms appear, horse owners are urged to contact their veterinarian immediately.
Event organizers are encouraged to work closely with show veterinarians to assess the risks of holding equine gatherings during this multi-state outbreak. “Cancellation or postponement of events may be important to stop continued spread of disease. If events do take place, we recommend short-timed health certificates within 72 hours of arrival and increasing biosecurity practices on site,” said the department. Additional exhibition requirements could be introduced based on risk assessment.
Horse owners planning travel should also consult their veterinarians about potential risks at upcoming equine events. Because EHV is common in the environment, strong biosecurity measures remain essential for preventing disease transmission.
States may implement new movement restrictions or import requirements for horses during this outbreak period. Owners should check with destination states before traveling to ensure compliance with any restrictions.
EHV-1 can spread through direct horse-to-horse contact via nasal discharge or aerosol droplets; infected animals may not show symptoms but can still transmit the virus. Indirect transmission can occur through contaminated surfaces—such as stalls, water buckets, feed containers, tack—or by people carrying the virus on hands or clothing between animals. Good biosecurity practices include thorough cleaning and disinfection of all surfaces and equipment coming into contact with affected horses; individuals working with multiple animals should follow proper disinfection protocols.
For more information or assistance regarding animal health concerns related to this outbreak, contact the Animal Health Program at 503-986-4680.
