The worst is over in the unusual equine herpesvirus type-1 (EHV-1) outbreak that led to the death of 10 horses and has affected the remaining equine population at the University of Findlay’s English riding facility in Findlay, Ohio, since Jan. 12. Veterinarians have not detected any new cases of the respiratory and neurological illness in the last five days at the facility. Ten horses with neurologic signs are stable and under treatment at Findlay, while two horses remained in critical condition at The Ohio State University’s veterinary teaching hospital Jan. 28. Epidemiological studies are being completed to figure out where the virus came from, and scientists are comparing the strain to others found in past outbreaks.

The EHV-1 organism can spread quickly from horse to horse through aerosol droplets in the air or contact with equipment used by affected horses (only in the very early stages and not for a long time as the virus does not live in the environment for a long time) and can cause three different forms of disease, including rhinopneumonitis (a respiratory disease of mostly young horses), abortions in pregnant mares, and neurologic disease. The stricken horses in Findlay showed clinical signs of the respiratory and neurological forms. There are at least seven other strains of equine herpesviruses, named in order of their discovery. (See article #32 at www.TheHorse.com for more on herpesviruses.) The neurologic form of EHV-1 often is survivable with supportive care, but unfortunately once a horse is recumbent, it is difficult to nurse the horse back to health