An outbreak of Equine Herpesvirus Myeloencephalopathy that began in Texas at the Women’s Professional Rodeo Association World Finals and Elite Barrel Race event Nov 5-9 has spread to Oklahoma, Washington, New Mexico, Colorado, Arizona and Louisiana. A horse testing positive for the disease in Maryland had no connection to the world finals.
No U.S. Equestrian Federation competitions have been affected, but USEF notes this situation should remind everyone to take biosecurity measures at competitions. That includes ensuring compliance with USEF EHV-1 and Influenza vaccination requirement (within 6 months of entry to a venue), taking temperature twice daily and recording them and mmediate reporting of a horse with a temperature over 101.5 fahrenheit. That is a USEF rule.
Also, USEF advises observing clinical signs of disease and reporting them to the veterinarian, avoid sharing equipment without cleaning and disinfecting between uses, limit horse-to-horse contact, maintaining separation while walking, riding or driving
In addition, limit the individuals touching horses to essential personnel and make sure horse trailers are properly cleaned and disinfected between loads of horses especially those loads containing sick horses.
While EHV-1 most commonly causes respiratory disease, some strains causes neurologic signs as a result of inflammation of the blood vessels and activation of blood coagulation within the brain and spinal cord. Neurologic signs occur as a result of a lack of blood flow and resulting damage to the brain or spinal cord; this disease manifestation is known as Equine Herpesvirus Myeloencephalopathy,
Classic clinical signs of EHM include fever, swelling/stocking up of the limbs, hind limb weakness, and urine dribbling. Some horses are more severely affected and display behavior changes, signs of cranial nerve dysfunction, seizures, and inability to stand. While EHM is a serious disease, the majority of cases are not fatal. In most outbreaks of EHM, 60-70 percent of affected horses recover with treatment and supportive care. Veterinary evaluation and isolation of exposed or affected horses is crucial.
A seminar for horse owners on EHV-1 updates will be held Nov. 25 from 8-9:30 p.m. It is being presented by the American Association of Equine Practitioners and the Equine Disease Communication Center. Register at this link.
With the National Finals Rodeo starting Dec 4 in Las Vegas, the following precautions have been issued:
For accurate and reliable information regarding the clinical signs and transmission of EHV-1, visit the Equine Disease Communications Center: https://www.equinediseasecc.org/equine-herpesvirus