Detection of a neurological illness in Virginia thought to be equine herpesvirus-1 (EHV-1) myeloencephalopathy was recently confirmed as such at several laboratories throughout the United States.

The organism causing EHV-1 can cause three different forms of the disease–rhinopneumonitis, a respiratory disease of mostly young horses; abortions in pregnant mares; and this neurologic disease. There are at least seven other strains of equine herpesviruses, named in order of their discovery. (See Article Quick Find #32 at www.TheHorse.com for more on herpesviruses.) 

Four horses at Fox Chase Farm in Middleburg, Va., displayed the mysterious symptoms of the neurological form of EHV-1 in late April. Three of the horses were euthanized and one pony recovered with supportive care. (See Article Quick Find #3585 at www.TheHorse.com). 

Joseph P. Garvin, DVM, is the laboratory director of the Virginia Department of Agriculture and Consumer Services’ Warrenton Regional Animal Health Laboratory, where the autopsies of the second and third horses were performed. “No more cases surfaced–only the ones at the original premise,” said Garvin. “It’s still not known where it came from. It could have come from any number of places