Prevalence of bovine tuberculosis and characterization of the members of the Mycobacterium tuberculosis complex from slaughtered cattle in Rwanda

Abstract

BackgroundBovine tuberculosis (bTB) is an endemic disease in Rwanda, but little is known about its prevalence and causative mycobacterial species. The disease causes tremendous losses in livestock and wildlife and remains a significant threat to public health.Materials and methodsA cross-sectional study employing a systematic random sampling of cattle (n = 300) with the collection of retropharyngeal lymph nodes and tonsils (n = 300) irrespective of granulomatous lesions was carried out in six abattoirs to investigate the prevalence and identify mycobacterial species using culture, acid-fast bacteria staining, polymerase chain reaction, and GeneXpert assay. Individual risk factors and the origin of samples were analysed for association with the prevalence.FindingsOf the 300 sample pools, six were collected with visible TB-like lesions. Our findings demonstrated the presence ofMycobacterium tuberculosiscomplex (MTBC) in 1.7% (5/300) of sampled slaughtered cattle.Mycobacterium boviswas isolated from 1.3% (4/300) animals while one case was caused by a rifampicin-resistant (RR)M.tuberculosis. Non-tuberculous mycobacteria were identified in 12.0% (36/300) of the sampled cattle. There were no significant associations between the prevalence and abattoir category, age, sex, and breeds of slaughtered cattle.ConclusionsThis study is the first in Rwanda to isolate bothM.bovisand RRM.tuberculosisin slaughtered cattle indicating that bTB is present in Rwanda with a low prevalence. The isolation of RRM.tuberculosisfrom cattle indicates possible zooanthroponotic transmission ofM.tuberculosisand close human-cattle contact. To protect humans against occupational zoonotic diseases, it is essential to control bTB in cattle and raise the awareness among all occupational groups as well as reinforce biosafety at the farm level and in the abattoirs.