Morphological diagnosis of Johne’s disease: a case report in cattle

Abstract

The present case report deals with the morphological (gross and histopathological) and histochemical characterization ofJohne’s disease in a cow. The carcass was presented in a hidebound condition with sunken eyes and with a history of persistent andnonresponsive diarrhea. Necropsy revealed generalized gelatinization of the visceral and peripheral fat. Thorough gross examinationunveiled major pathological changes in the digestive tract. The gallbladder was distended, with severely thickened walls and bloodmixed with bile. The small intestine was severely congested and the mesenteric lymph nodes were enlarged. The opening of the smallintestine showed marked thickening of the intestinal walls, with a corrugated appearance. Diffuse granulomatous lesions were observedin the mesenteric lymph nodes. Histopathological examination revealed severe infiltration of intestinal layers and mesenteric lymphnodes by macrophages, lymphocytes, and epithelioid cells with multiple Langhans giant cells. Ziehl–Neelsen staining demonstratedmultiple acid-fast bacilli in the cytoplasm of macrophages from impression smears.