ANATOMOPATHOLOGY OF PARATUBERCULOSIS IN DAIRY CATTLE FROM RESENDE - RJ

Paratuberculosis is an infectious disease caused by Mycobacterium avium subsp. paratuberculosis (Map) characterized by chronic granulomatous enteritis. The purpose of this work was to report the anatomopathology of three cases of paratuberculosis in autochthonous dairy cattle from Resende, Rio de Janeiro, Brazil. Animals presented characteristic clinical symptoms of paratuberculosis and were seroreactive to ELISA. They were euthanized and necropsied. Small and large intestines, mesenteric lymph nodes and ileocecal valve samples were collected and processed for histopathology and bacteriology. Tissues were fixed in 10% buffered formalin, processed for paraffin inclusion, and stained by HE (haemathoxilin-eosin) and ZN (Ziehl-Neelsen). Macroscopic alterations such as small intestine wall segmental thickness, mucosal hyperaemia, and corrugation were observed. Ileocaecal valve emaciation, evident mesenteric lymphadenomegally, and lymphangiectasy were also present. The main histopathological findings were enteritis, lymphangitis and granulomatous lymphadenitis. Intestinal lesions were mainly restricted to mucosa and submucosa of jejune and ileum, characterized by inflammatory infiltration of lymphocytes, eosinophils, epithelioid macrophages, and scarce giant Langhan’s–type cells. Numerous acid-fast bacilli were observed into macrophages on the top of villi, lamina propria and lymph nodes parenchyma. Anatomopathology was characteristic for the disease and was considered a valuable tool for the diagnosis of paratuberculosis.