Tuberculosis suspicion in Chadian health centers: evaluation of the management system and zoonotic aspect of the disease

Abstract

INTRODUCTION: In 2016, 1.7 million of people died from tuberculosis caused by bacteria of the Mycobacterium tuberculosis complex, of which some may have a zoonotic origin. The mycobacterial disease endemicity is worrying in Africa owing to the absence of a reliable strategy in relation with disease ecology. The objective of the study is to assess the reliability of different components of the tuberculosis research and surveillance system in Chad. METHODS: in 2012, a cross-sectional study was conducted in order to assess the importance of tuberculosis in southern Chad and Lake Chad regions. Nine health centers located in areas with a high proportion of pastoralist populations were visited. Microbiological and molecular diagnoses were performed on samples collected from tuberculosis-suspected patients. RESULTS: we assessed one quarter (26.4%) of all the suspected cases in our study site, as estimated in 2012. More males were infected than females (329 versus 147) and most of the suspected cases were aged between 16 and 60 years. Of the 478 sputa collected, 77 were identified as infected with acid fast bacilli, from which 71 were of the genus Mycobacterium, including 45 Mycobacterium tuberculosis, a case of co-infection Mycobacterium bovis/Mycobacterium avium, and 25 non-tuberculosis mycobacteria. Twelve suspected cases harbored other mycobacteria. CONCLUSION: the co-infection Mycobacterium bovis/Mycobacterium avium found in a poultry farmer was the first such co-infection in Chad related to human tuberculosis. Indeed, this finding highlights the importance of the zoonotic aspect of mycobacterial diseases and proves the value of molecular characterization in the tuberculosis surveillance.