Two horses at Lone Star Park have tested positive for equine piroplasmosis, a tick-borne disease caused by parasites that affects horses, donkeys, mules, and zebras. In addition, a third horse that left Lone Star and had been shipped to New Mexico also tested positive for the disease.

According to officials at the Texas track, one of the horses, Seven Shooter, is trained by 2010 leading trainer Bret Calhoun, while another, Street Positioning, is trained by Kevin Favre. Brian House trains the horse that left for New Mexico.

As a result, horses in Calhoun's barn, as well as Favre's and House's horses, have been restricted from racing and training with other horses by the Texas Animal Health Commission, whose representative, Bobby Crozier, is on the grounds at Lone Star.

"Right now, we are cooperating fully with the efforts of both the Texas Animal Health Commission and the Texas Racing Commission," Lone Star president and general manager Drew Shubeck said in a statement. "We are following the direction (of Crozier), who has instructed us to place restrictions on the horses of the affected trainers. We will continue to work with the TAHC and Dr. Ken Quirk, the chief veterinarian for the Texas Racing Commission, to resolve this issue as quickly as possible