Horse in Clackamas County, OR euthanized after testing

Veterinarians are legally required to report suspected cases to the state.

CLACKAMAS COUNTY, Ore. (KOIN) — A horse from Clackamas County recently tested positive for Equine Herpesvirus, state officials said.

According to the Oregon Department of Agriculture (ODA), the owners of the horse called a private veterinarian to examine the animal and collect a sample for testing after experiencing neurologic symptoms. The horse was later humanely euthanized.

ODA said a California laboratory confirmed EHV-1 on May 31. The agency added that veterinarians are legally responsible for immediately reporting all suspected cases.

“The horse owner reports the animal recently traveled to the 2022 State Oregon High School Equestrian (OHSET) Teams Championship,” the ODA said. “OHSET was held at the First Interstate Bank Expo Center in Redmond, Oregon, from May 12-15. A second horse from the same ranch who also traveled to OHSET is doing well, recovering from initial respiratory symptoms. However, an ODA District Veterinarian placed a quarantine on the farm following state and national guidelines.”

The ODA State Veterinarian is working with OHSET to evaluate the potential exposure risk at the state event, and event coordinators are working to contact exhibitors, said the announcement.

All horse owners who believe that their horse may have been exposed to the virus should monitor their animal’s temperature twice daily and call their veterinarian if they see any symptoms.

State officials say the virus is highly contagious and spreads via aerosolized secretions from infected coughing horses, direct and indirect contact with nasal secretions and fetal fluids. EHV-1 typically has an incubation period of two to 10 days.

Respiratory shedding of the virus generally occurs for 7-10 days but may persist longer in infected horses, the press release added.

ODA said following basic biosecurity practices is an essential factor in reducing the risk of exposure to all contagious equine diseases. Those basic measures include limiting horse-to-horse contact, avoiding the use of communal water sources and only using thoroughly cleaned and disinfected equipment between uses if sharing.

For more information about the virus, visit here.