First isolation of Mycobacterium tuberculosis from suspected cases of bovine tuberculosis in rural abattoirs in Chad.

BACKGROUND: Tuberculosis is a zoonotic disease affecting domestic ruminants, human worldwide and caused by Mycobacterium bovis that belongs to Mycobacterium tuberculosis complex. In Chad, tuberculosis caused by Mycobacterium bovis was previously isolated from both suspected patients and domestic ruminant carcass. OBJECTIVES: The objective of our study is to assess the multispecies feature of causative agents of tuberculosis infection in domestic ruminants destined to human consumption. METHODS: In 2012, a cross-sectional study was conducted in 7 abattoirs in southern Chad. Bacteriology and molecular typing were performed on collected lesions. RESULTS: Samples were taken on suspected lesions carcass from local cattle breeds as 234 Arabic, 91 Fulani, 1 Bogolodje and 1 cross breeds. Among them, 25 were defined as “total seizures” and 302 others as “partial seizures”. These lesions were majority within the age group from 3 to 12 years old. Mainly Mycobacterium bovis strains were isolated from 42 suspected bovine carcasses. Mycobacterium tuberculosis strain was isolated from a female Fulani 6 years old. However, 112 of these carcass were males and 215 females and sex has significant influence on tuberculosis infection in cattle (p = 0, 04, OR = 1, 7 IC OR 95%: 1,039 − 3,089). Thus, females were twice as likely to be at risk as males and ten (3%) suspected cattle carcass were due to Non Tuberculosis Mycobacteria infection. CONCLUSION: As previously show by other studies performed in Chad, causatives agents of lesions suspected in abattoir as tuberculosis lesions are usually diverse. However, M.bovis was confirmed in bovine carcass but M.tuberculosis was also isolated.