An outbreak of Equine Herpesvirus (EHV-1) in California in the US has forced the postponement of many events, following an order from the California Department of Food and Agriculture (CDFA).
Equine herpesvirus myeloencephalopathy (EHM) has been detected in multiple horses in several counties in California, and at least five deaths have been reported.
Equine herpesvirus causes respiratory disease, abortion, neonatal death, and the neurological disease known as EHM. It spreads in aerosolized secretions, by direct contact, and by contact with surfaces containing infected secretions. Shedding of the virus generally occurs for 7 to 10 days.
To reduce disease spread, the California State Veterinarian recommends that all hunter/jumper events (the most affected group) will be postponed for the next 28 days, all equine events have been postponed for the next 14 days, and all non-essential horse movements postponed for at least 14 days.
The recommendation considers an event when horses from different home premises are brought together at a single location and include, but are not limited to: competitions of any discipline (in state or out of state), rodeos, educational riding clinics, and any travel of horses to an outside facility for lessons or casual/social gathering, etc. Sanctioned horse racing tracks are exempt from this recommendation.
The outbreak has forced the cancellation of the 2022 FEI Longines Jumping Nations Cup event that was to be held in San Juan Capistrano from May 10 to 15, 2022. The event was the third qualifier in the Nations Cup series, and one of three North/ Central America and Caribbean Division events. The cancellation by organisers Blenheim EquiSports has the full support of both the FEI and the US Equestrian Federation (USEF).
FEI Veterinary Director Göran Akerström said the FEI had been closely monitoring the development of the EHV-1 outbreak in California. “Stopping the movement of horses is key to prevent further spread of the virus,” he said.
USEF CEO Bill Moroney said that while the cancellation was disappointing for organiser and competitors, “the safety and welfare of our members and their horses is our top priority and most important responsibility. We are fully supportive of this decision while the mitigation and containment efforts for EHV-1 are still ongoing in California.”
Horse owners must immediately isolate any horses exhibiting neurologic signs and consult their veterinarian under state reporting requirements. Owners must practice good biosecurity when they move horses in emergency situations or for veterinary care; avoid other horses and don’t share tack/equipment that hasn’t been properly cleaned and disinfected, including farrier and veterinary equipment.