Dr. Doug Byars, head of the internal medicine unit at Haygard-Davidson-McGee veterinary firm in Lexington, Ky., reported that examinations on three farms of 150 Thoroughbred yearlings revealed no incidence of pericarditis. "This is a positive finding," said Byars. "We're very pleased."Dr. Johanna Reimer, a specialist in veterinary cardiology with the Rood and Riddle Equine Hospital in Lexington, said she has seen no new acute pericarditis cases recently. She said she has been called out to look at several horses showing various signs of illness (such as fever), but has not diagnosed pericarditis.Figures Dr. Reimer gathered from Rood and Riddle, Hagyard-Davidson-McGee, and the Kentucky Livestock Disease Diagnostic Center showed that only 10 of the diagnosed pericarditis cases have been Thoroughbred yearlings. With an estimated Thoroughbred yearling population in Kentucky of about 9,000, that means that only 0.1% of the yearlings have been affected.