Necrotic enteritis in broiler chickens. II. Pathology and proposed pathogenesis

The intestines from 124 dead, sick and normal broiler chickens from 24 cases of necrotic enteritis were subjected to histological examination. Tissue sections from the duodenum, jejunum, ileum and ceca from each broiler were examined histologically for lesions of necrotic enteritis and the presence of coccidia. Lesions of necrotic enteritis were present in one or more areas of the intestine in all but six of 94 dead or sick birds and they were most common and severe in the jejunum. Coccidia were found in only small numbers in both diseased and normal birds. Brown and Brenn stained sections showed Gram-positive bacilli intimately associated with early necrotic lesions on the tips of villi. Tissue sections from the intestines of sick birds permitted a proposed pathogenesis for this disease with the lesion starting at the tips of villi. The similarity in pathogenesis and pathological lesions in this disease of broilers and Clostridium perfringens type C enteritis in baby pigs is discussed.