In many horses, the first or only sign of EHV-1 infection is fever, which can go undetected. | Photo: Stephanie L. Church/The Horse

On Oct. 5, officials at the Florida Department of Agriculture and Consumer Services (FDACS) confirmed a horse in Palm Beach County with equine herpesvirus myeloencephalopathy (EHM). The 18-year-old Warmblood gelding began showing clinical signs on Oct. 3. Signs included ataxia (loss of muscle control), hind-end weakness, and inability to urinate. He had been vaccinated and is reported as affected and alive.

EHV 101

Herpesvirus is highly contagious among horses and can cause a variety of ailments in equids, including rhinopneumonitis (a respiratory disease usually found in young horses), abortion in broodmares, and equine herpesvirus myeloencephalitis (the neurologic form).

In many horses, the first or only sign of EHV-1 infection is fever, which can go undetected. In addition to fever, other common signs of EHV-1 infection in young horses include cough, decreased appetite, depression, and a nasal discharge. Pregnant mares typically show no signs of infection before they abort, and abortions usually occur late in gestation (around eight months) but can be earlier. Abortions can occur anywhere from two weeks to several months following infection with EHV-1