EHV Confirmed in King County, Washington, Horse
The Equine Disease Communication Center (EDCC) reported Dec. 15 that a Washington state horse has tested positive for equine herpesvirus-1 (EHV-1).

“(The) Washington State Department of Agriculture confirmed an equine herpesvirus-1 neurotropic genome strain in a horse in King County,” the EDCC said on its website. “The 13-year-old Haflinger gelding has no neurological symptoms at this time. The facility is under quarantine and the remaining horses are having their temperatures taken twice daily and strict biosecurity practices are in place, as well.”

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 myeloencephalopathy (the neurologic form). In many horses, fever is the only sign of EHV-1 infection, 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.

Horses with the neurologic form usually have a fever at the onset of the disease and might show signs of a respiratory infection. A few days later, neurologic signs such as ataxia (incoordination), weakness or paralysis of the fore- and hind limbs, urine retention and dribbling, loss of tail tone, and recumbency (inability to rise) develop.