Two of the four affected horses have been euthanized.

The mare’s boarding facility had pre-emptively enacted movement restrictions following a mare in another province showing clinical signs days earlier.

Thirty-one horses were exposed and their Washington County facility is now under quarantine.

The California Department of Food and Agriculture continues to monitor horses from the Sonoma County show and the index case’s home premises.

Another mare has shown neurologic signs but has tested negative for EHV-1.

The CDFA reports one neurologic, one febrile, four suspected cases that tested negative, and one euthanized horse.