Case-control study of factors associated with fibrinous pericarditis among horses in central Kentucky during spring 2001

OBJECTIVE: To identify factors significantly associated with an epidemic of fibrinous pericarditis during spring 2001 among horses in central Kentucky. DESIGN: Case-control study. ANIMALS: 38 horses with fibrinous pericarditis and 30 control horses examined for other reasons. PROCEDURE: A questionnaire was developed to solicit information regarding a wide range of management practices and environmental exposures from farm owners or managers. RESULTS: The following factors were found in bivariate analyses to be significantly associated with an increased risk of pericarditis: being from a farm with mares and foals affected by mare reproductive loss syndrome, exposure to Eastern tent caterpillars in or around horse pastures, younger age, shorter duration of residence in Kentucky and at the farm of current residence, being fed hay grown outside Kentucky, a lack of access to pond water, access to orchard grass for grazing, and a lack of direct contact with cattle. In multivariate logistic regression analyses, only variables related to caterpillar exposure and age were significantly associated with fibrinous pericarditis. CONCLUSIONS AND CLINICAL RELVANCE: Results suggest that fibrinous pericarditis in horses may be associated with mare reproductive loss syndrome. Exposure to Eastern tent caterpillars was the greatest risk factor for development of fibrinous pericarditis. The distribution of times of diagnosis of fibrinous pericarditis was consistent with a point-source epidemic.