Two additional Oregon horses are now showing neurological signs of equine herpesvirus type-1 (EHV-1), bringing the total number of horses developing neurological signs to four, according to the Oregon Department of Agriculture. In addition, another five horses exposed to EHV-1 have developed fevers, but are not showing neurological signs at this time. 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 or other horses 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, April 19-20, as well as at the High Prarie Area in Eugene, Oregon from April 25-26. 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.
State Veterinarian Dr. Brad LeaMaster has issued the following recommendation:
“All horses that attended the OHSET Willamette district meet on April 16-18 should refrain from any further shows or gatherings for the next 28 days and impose a self quarantine. Owners of stablemates of these OHSET horses should consult with their veterinarians to assess risk of exposure. High-risk horses should also refrain from shows or gatherings. The responsible thing for OHSET Willamette District attendees to do at this time is to stay home and monitor their horse. Call your veterinarian if you suspect any signs of illness.”
EHV-1 is not transmissible to people. The virus is naturally occurring and widespread in the equine population. It is a common virus and may lie dormant for long periods of time, then re-activate during a period of stress, which can result in clinical disease. EHV-1 can cause respiratory disease, abortions in pregnant mares, neurologic disease, and in severe cases, death. The most common way for EHV-1 to spread is by direct horse-to-horse contact. The virus can also spread through contaminated equipment, clothing and hands. Symptoms include fever, decreased coordination, nasal discharge, urine dribbling, loss of tail tone, hind limb weakness, leaning against a wall or fence to maintain balance, lethargy, and the inability to rise. While there is no cure, the symptoms of the disease may be treatable.