Two additional Oregon horses have developed neurologic signs of equine herpesvirus-1 (EHV-1), bringing the total number of horses showing neurologic signs to four, the Oregon Department of Agriculture (ODA) reported May 7.

In addition, another five horses exposed to EHV-1 have developed fevers but have not showed neurologic signs. All horses involved are under active observation by owners and their veterinarians. Eight farms are currently under quarantine—six in Marion County and two in Polk County.

The infected horses and others exposed at the quarantined facilities attended several recent events, including:

• An Oregon High School Equestrian Team (OHSET) meet at the Linn County Fairgrounds on April 16-19; and
• Rodeo events at Branton Arena in Jefferson, Oregon, on April 19-20 and the High Prairie Arena in Eugene, Oregon, April 25-26.

The ODA continues to investigate the potential of any additional exposures at this time. In addition, ODA is working to notify owners of horses that have been potentially exposed and has notified Oregon equine veterinarians