M.Sc. Dissertation
This cross sectional study was carried out between August and December 2015 in order to determine the presence of Mycobacterial infections in slaughter cattle and assess the occurrence of Mycobacteria in the slaughter facility environment in Iringa Municipality, Tanzania. A total of 3817 slaughter cattle were examined tuberculous like lesions in lymph nodes, lungs and other visceral organs. Tissues with suspect lesions were collected for laboratory analysis. Effluent samples in the slaughter facility environment were collected early and late in the slaughter process in order to determine environmental contamination with Mycobacteria. Tissue samples were cultured using standard laboratory procedures and Mycobacterial species were identified using a multiplex PCR. Of the carcasses examined, 35 (0.9%) had lesions suggestive of tuberculosis. Ten of the 35(28.6%) samples culture positive and 1/10 (10%) was confirmed as M. bovis. The remaining 9 (90%) of isolates were non-tuberculous Mycobacteria (NTMs) which were identified as M. lentiflavum (3), M. intracellulare/M. indicuspranii (2), M. lentiflavum/palustre/simiae, (2) M. goodie (1) and M. smegmatis (1). Mycobacteria were detected in 25/172 (14.5%) of effluents samples. Five of the positive (20%) effluent samples were confirmed to be M. bovis and 20 (80%) were M. kansasii. This demonstrates that Mycobacteria are prevalent in slaughter cattle in Iringa Municipality, which is a public health concern. Notably, the majority of lesions were caused by NTM’s. This study is the first to detect Mycobacteria in slaughter facility effluents in Tanzania. Routine disinfection of slaughter facility environment will minimize chances for persistent contamination. Further epidemiologic studies to establish the role of NTM’s in clinical livestock disease are recommended. Studies on the magnitude of environmental contamination due to discharges of untreated slaughter facility effluents are also important.