A histopathological report on multibacillary form of naturally occurring paratuberculosis infection in buffaloes

Paratuberculosis is chronic enteritis of the domestic ruminants caused by Mycobacterium avium subsp. paratuberculosis. Post-mortem examination of twelve naturally infected (displaying disease associated gut lesions) adult buffaloes was performed to accomplish explorative histopathology. Tissue samples were collected specifically from the small intestine and associated lymphoid organs. Histopathology revealed diffused multibacillary lesions, linked with significant granulomatous enteritis distressing different locations of the small intestine. These lesions were produced by the infiltration of epithelioid macrophages, lymphocytes and plasma cells. Ziehl-Neelsen staining of the affected tissues demonstrated, the foamy cytoplasm of the epithelioid macrophages containing large numbers of acid-fast bacilli. Multifocal granulomatous types of lesions were found in the ileal lymph nodes. The most conspicuous macroscopic finding was the thickening of the intestinal wall chiefly associated with microscopic changes of the mucosa and submucosa. Infection status was also confirmed by using ELISA in the study. Further investigations are required to emphasize the zoonotic role of M. Avium subsp. paratuberculosis.

Key words: Buffalo, Paratuberculosis, Histopathology, Small intestine, Lymph node