The quarantine affected barns in which horses trained by Asmussen, Ronny Werner, Paul McGee, and Bill Cesare are stabled. Among the horses sidelined by the quarantine were Don't Get Mad, the Derby Trial (gr. III) winner and fourth-place finisher in the Kentucky Derby (gr. I), and Summerly, the Kentucky Oaks (gr. I) winner. While under quarantine, horses in the three barns had been able to train only during limited hours in the late morning or evening. Horses trained by McGee and Cesare were released from quarantine June 4, while Werner's horses were released two days later.
Horses from the last of three Churchill Downs barns under quarantine because of an equine herpesvirus outbreak resumed regular training hours and racing June 12. Kentucky Department of Agriculture officials released from quarantine most of the horses under trainer Steve Asmussen's care. The horses include 29 stabled in Asmussen's barn, and four of the seven that had been moved to another barn the week of June 6 after they initially tested positive for the presence of the virus, said John Asher, vice president of communications for Churchill.Three barns at the track were placed under quarantine in mid-May after horses began showing symptoms of equine herpesvirus, an upper respiratory and neurological ailment . Two horses that showed extreme symptoms of the disease were euthanized.