Molecular characterization of Mycobacterium bovis isolated from camels slaughtered for human consumption in Northeastern Nigeria and the public health implication

Abstract

Introduction: although, camels serve as sources of food, transportation, work and income in Northern Nigeria, they are also a potential source of zoonotic diseases such as tuberculosis (TB). Camel TB is an important emerging public health problem in sub-Saharan Africa. However, there exist limited epidemiological data on the disease in Nigeria. Methods: we conducted a cross-sectional study among camels in Maiduguri, Northeast Nigeria. Lesions suggestive of TB were collected from camels slaughtered at Maiduguri Abattoir following post-mortem examination. The lesions were subjected to acid fast microscopy (AFB) and culture. Furthermore, isolates were tested for Mycobacterium tuberculosis complex (MTBC) using SD Bioline and confirmed by spoligotyping. Results: twenty (16.26%) out of 123 camels inspected had gross TB lesions; 50% of which were positive for AFB and 60% were identified by culture. Animals with poor body conditions had higher TB lesions (P < 0.05). There was no significant difference in the occurrence of TB lesions between male and female camels. SD Bioline identified four of the 12 isolates as MTBC which were further confirmed by spoligotyping to be M. bovis, belonging to the clonal complex SB0944 and lack spacer 30, that is dominant in West Africa. Conclusion: the isolation and confirmation of the unique dominant M. bovis strain from camels underscore the importance of molecular epidemiology of tuberculosis in camels and the possibility of cattle to camel transmission of tuberculosis. We strongly recommend implementation of One Health policies towards addressing threat posed by tuberculosis in camels in Nigeria.