Two additional California horses have tested positive for neurologic equine herpesvirus-1 (EHV-1) after an Oldenburg mare was diagnosed with the disease on Aug. 23. The most recent cases were confirmed on Aug. 24, according to a statement from the California Department of Food and Agriculture (CDFA).

The only clinical sign exhibited by the most recently confirmed cases was a fever, the statement noted.

"The affected premises is under quarantine and the 13 other horses currently on the property are being monitored," the release said. "Current epidemiologic investigation findings indicate minimal risk of disease spread from this closed premises."

Further, the CDFA indicated that this case has "no direct link" to the widespread EHV-1 outbreak that took place in the western United States and Canada in May and June of this year