Intestinal necrosis in calves with blackleg: A novel presentation of Clostridium chauvoei infection.

Blackleg is a necrotizing, hemorrhagic, and emphysematous myositis of ruminants caused by Clostridium chauvoei. Here, we report a previously unrecognized manifestation of blackleg in calves characterized by multifocal, transmural intestinal necrosis. Two, 3- and 6-month-old beef calves without history of vaccination against clostridial diseases died following acute muscular disease. Gross and histologic changes were consistent with blackleg, including emphysematous and necrotizing myositis with gram-positive bacilli. Both calves had sharply demarcated areas of transmural, intestinal coagulative necrosis with vascular congestion, hemorrhage, fibrinoid necrosis, and thrombosis. Infection was confirmed by positive C. chauvoei immunolabeling in skeletal muscles of both calves and the small intestine of one case, and by polymerase chain reaction (PCR) in the skeletal muscles and intestines of both calves. Intestinal necrosis has not been previously reported in association with blackleg. Systematic examination, including the intestines, in cases of blackleg is recommended.