An equine herpes virus first detected in Palm Beach County, Fla., has killed another horse.

A spokesman from the Florida Department of Agriculture said the horse died Friday at Payso Park, a 500-horse facility in Martin County now under a state-mandated quarantine. It is believed to be the fifth to die of the recent virus, called EHV-1, Equine Rhinopneumontis, commonly known as equine herpes virus.

Agency officials believe the horse caught the disease at Wellington’s Palm Beach Equine Sports Complex, where 10 known cases of the disease are linked. The filly had a low-grade fever Monday and died yesterday.

The infection began with five horses imported from Europe that were brought to Florida from a New York animal import station