The California Department of Food & Agriculture’s Animal Health branch is conducting a full epidemiologic examination at the Orange County property where five horses have been tested positive for the equine herpes virus 1 (EHV-1).

Two cases of EHV-1, a neurological form of the disease, were confirmed on Friday, following the announcement of two confirmed cases on Thursday. The first case of EHV-1 was confirmed on Wednesday.

However, no new case was found on Saturday.

The department has prescribed no movement of horses on or off the Orange County property.

Meanwhile, North Caroline State University Prof. Sam Jones confirmed, "The mare with confirmed EHV-1 in our hospital isolation facility is continuing to be treating and her condition is improving daily."

Equine herpesvirus myeloencephalopathy (EHM), the neurological form of the EHV-1, is a fatal disease of horses. But it can be avoided by instituting standard biosecurity measures, such as isolating all horses entering the premises- including those returning from shows.