In many horses, the only sign of EHV-1 infection is fever, which can go undetected. | Photo: Kevin Thompson/The Horse

State animal health officials confirmed April 10 that a horse in Lincoln County, South Dakota, has tested positive for equine herpesvirus-1 (EHV-1).

The horse developed neurologic signs, including incoordination and difficulty walking, and received treatment at a local veterinary clinic. Laboratory testing confirmed the disease.

The affected horse has traveled extensively in South Dakota for cutting and sorting events in the past few weeks