No new cases of the equine herpes virus 1 (EHV-1) were detected on Saturday at an Orange County, California, property where five horses have now tested positive for the neurological form of the disease.
The property, described as a large multi-discipline facility by the California Department of Food and Agriculture, is under quarantine, with no movement of horses on or off the property.
The two most recent cases were confirmed by the department on Friday, following two confirmed cases on Thursday.
The first case, in a gelding, was reported by the department on Wednesday.
The department's Animal Health branch is conducting a full epidemiologic investigation at the affected premises.