Two horses in Deschutes County, Oregon, have been euthanized and two ranches are under quarantine due to neurologic equine herpesvirus (EHV-1), according to information from the Equine Disease Communication Center (EDCC). Neurologic equine herpesvirus is also known at equine herpesvirus myeloencephalopathy (EHM).

The Oregon Department of Agriculture reported that a horse from Deschutes County tested positive for equine herpesvirus (EHV-1) on May 4, 2022. The horse had recently attended the Oregon Horse Center at the Prairie Arena in Eugene, Oregon, from April 22-25. The horse has not attended any other events since that time.

This horse showed neurological signs but did not show signs of nasal discharge or an elevated temperature commonly seen with EHV-1 infection. Unfortunately, due to delayed reporting, this case was only recently shared with the Oregon Department of Agriculture.

A second horse from Deschutes County became symptomatic on May 13. The infected horse attended a show on May 6-7, also at the Oregon Horse Center in Eugene. Confirmation of EHV-1 came from the Oregon State University Oregon Veterinary Diagnostic Laboratory on May 16.

Both horses were humanely euthanized and both ranches are currently under quarantine. The required quarantines will last a minimum of 28 days.

To learn more read this Fact Sheet from the EDCC and AAEP.