Golden Gate Fields, Bay Meadows and Pleasanton were placed under quarantine Dec. 29 after a horse from Golden Gate was diagnosed as positive for the neurogenic strain of equine herpesvirus-1 (EHV-1).

The California Horse Racing Board (CHRB) Friday issued an advisory placing the three tracks under quarantine as one facility. Racing will continue as normal at Golden Gate, but no horses may leave those facilities and horses that enter those tracks will then be subject to EHV-1 quarantine conditions.

Royal Brass, a 3-year-old gelding trained by Lloyd Mason, “showed signs of neurological discomfort” following exercise on the track at Golden Gate Dec. 28, said track spokesman Tom Ferrall. Royal Brass was sent to University of California-Davis for testing and the EHV-1 finding was confirmed there Friday morning. Three horses entered Friday by Mason were scratched and all of his barn’s horses were to be tested. The quarantine restrictions will remain in place for a minimum of 10 days.

About 2,100 horses are affected by the quarantine in Northern California–1,300 stabled at Golden Gate, 600 from Bay Meadows and 200 based at Pleasanton