ehv-1 in california

On March 26 the California Department of Food and Agriculture (CDFA) announced that a 3-year-old Thoroughbred filly from Alameda County, who had exhibited severe neurologic signs of disease, tested positive for equine herpesvirus-1 (EHV-1).

The California Horse Racing Board confirmed in a separate statement March 26 that the filly had been stabled at Golden Gate Fields racetrack, in Berkeley, and was euthanized on March 23.

“California Department of Food and Agriculture veterinary personnel have inspected the barn and reviewed biosecurity procedures that had been put in place,” the CHRB said. “One barn of exposed horses has been placed under restricted quarantine with enhanced biosecurity measures and twice daily
temperature monitoring. At this time, there is no indication of additional cases.

“In addition to California Horse Racing Board (CHRB) and Golden Gate Fields management, CDFA personnel will continue to monitor the situation,” the CHRB said. “Horses have resumed entering and leaving Golden Gate” from barns not under quarantine.

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 herpes myeloencephalopathy (EHM, the neurologic form).

ehv-1 in california

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.

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.

Herpesvirus is easily spread by nose-to-nose or close contact with an infectious horse; sharing contaminated equipment including bits, buckets, and towels; or clothing, hands, or equipment of people who have recently had contact with an infectious horse. Routine biosecurity measures, including hygiene and basic cleaning and disinfection practices, should be in place at all times to help present disease spread.

Current EHV-1 vaccines might reduce viral shedding but are not protective against the neurologic form of the disease. Implementing routine biosecurity practices is the best way to minimize viral spread, and the best method of disease control is disease prevention.