Two Maryland horses test positive for neurologic form of equine herpesvirus. The cases are not connected to each other or recent cases in Florida. A precautionary "hold" order has been placed on four barns at Laurel Park Racetrack. Author: Mar 9, 2021 Two horses in Maryland have tested positive for the neurological form of equine herpesvirus type-1 (EHV-1), according to the Equine Disease Communication Center (EDCC). The two cases are not connected to each other, nor are they connected to recent cases in Florida. The Florida cases have raised concerns about the spread of a particularly aggressive form of EHV-1 from the Europe.