On June 22, the State Veterinarian’s Office of the Virginia Department of Agriculture and Consumer Services (VDACS) was informed two horses from the same barn tested positive for Equine Herpesvirus-1 (EHV-1). The infected horses were stabled at the Virginia Horse Center (VHC) during the Shenandoah Classic. Both horses were immediately moved off the grounds when they first exhibited symptoms. One horse is receiving medical care and is stable. The other horse was subsequently euthanized.
Approximately 80 exposed horses that were stabled in the same barn at the VHC have been placed under quarantine. All exposed horses are being monitored twice daily for fever (temperature over 101.50 F) and other clinical signs. No other horses at the horse show are considered exposed and the horse show will continue. However, the unexposed horses are having temperatures and clinical signs monitored out of an abundance of caution. The Virginia Horse Center is following their biosecurity plan and will remain open for business. There is no cause for alarm concerning the general horse population in Virginia.
EDCC Health Watch is an Equine Network marketing program that utilizes information from the Equine Disease Communication Center (EDCC) to create and disseminate verified equine disease reports. The EDCC is an independent nonprofit organization that is supported by industry donations in order to provide open access to infectious disease information.
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 EHM.
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 EHM 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 prevent 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.