Histopathological and molecular methods as complementary diagnostic in case of lymphadenopathies suggestive of bovine tuberculosis.

Abstract

Bovine tuberculosis (TB) is a chronically evolving zoonotic infectious disease caused by Mycobacterium bovis. Anatomopathological examination during post mortem inspection in bovines is the main resource engaged in sanitary slaughter; however, it is very troublesome since many granulomatous inflammatory processes have similar morphological characteristics. Thus, this study aims to use complementary diagnosis methods (histopathological and polymerase chain reaction - PCR assays) to confirm the macroscopic assessment of lymphadenopathies indicative of tuberculosis in bovines slaughtered in a refrigerated slaughterhouse in Tailândia city, PA, Brazil. Fifty‑one samples were collected from lesions indicative of tuberculosis in pre‑scapular and pre‑pectoral lymph nodes (or different lymphadenitis) in condemned carcasses. Histological processing employed routine techniques carried out at the Laboratory of Animal Pathology of the Federal Rural University of the Amazon, while the PCR assay was performed at the Bacteriology Laboratory of the Evandro Chagas Institute. Results showed that 1.96% of the histopathology samples corresponded to inflammatory processes typical of TB and that, in PCR, 4.25% of the samples had the amplification profile of the M. bovis species. These results indicate the importance of adding complementary methods to assist the sanitary inspection line and make inspection more efficient in its decisions.