Despite a slow in the rate at which confirmed cases of equine herpesvirus-1 (EHV-1) associated with the current outbreak are being reported, new horses are still testing positive for the disease. Believed to stem from a national cutting horse competition held in early May in Utah, the outbreak has now been active for more than a month since the first cases were confirmed in mid-May.

Although it’s not transmissible to humans, EHV-1 is highly contagious among horses and camelids, and it is generally passed from horse to horse via aerosol transmission (when affected animals sneeze/cough) and contact with nasal secretions. The disease can cause a variety of ailments in equines, including rhinopneumonitis (a respiratory disease usually found in young horses), abortion in broodmares, and myeloencephalopathy (EHM, the neurologic form). Myeloencephalopathy is characterized by fever, ataxia (incoordination), weakness or paralysis of the hind limbs, and incontinence.

Many animal health officials believe the outbreak is winding down, and several of the horses diagnosed early have been treated and released from quarantine