Zoonotic tuberculosis at the cattle–human–captive wildlife interface in Bangladesh: a systematic evidence map of Mycobacterium tuberculosis complex transmission and One Health control priorities

Résumé fourni par la source

Zoonotic tuberculosis (zTB) is caused by animal-adapted members of the Mycobacterium tuberculosis complex (MTBC). It is classically attributed to M. bovis, but M. orygis is increasingly recognised as an important MTBC member across South Asia. In low- and middle-income countries (LMICs), species-level identification of MTBC is rarely performed, so the etiology and true burden of zTB at the animal–human interface remain poorly defined. Bangladesh has endemic bovine tuberculosis (bTB), a rapidly expanding crossbred dairy sector, a large unpasteurised-milk chain, and a growing captive-wildlife population, yet evidence across cattle, captive wildlife, and humans has not been synthesised with explicit attention to diagnostic reliability. We conducted a systematic evidence map following the PRISMA 2020 statement. PubMed, Google Scholar, and BanglaJOL were searched from inception to June 2026; CAB Abstracts, Scopus, and Web of Science were not accessible, and this is declared as a limitation. Two reviewers independently screened records and extracted data. Prevalence studies were appraised with the Joanna Briggs Institute (JBI) checklist, and every study was assigned a level on a purpose-built five-level diagnostic evidence hierarchy for species-level MTBC confirmation (Level 1, whole-genome sequencing [WGS]/ phylogeny/ region-of-difference [RD] typing/ spoligotyping/ MLVA; through Level 5, tuberculin reactor or serology evidence only). Because reported prevalences derived from non-comparable diagnostic tests, findings are presented as a structured evidence map rather than a pooled meta-analysis; the rationale is stated explicitly. Thirty-seven studies met the inclusion criteria (24 on cattle and buffalo, 10 on captive wildlife, and 3 on humans), spanning 1974–2026. Most livestock studies relied on tuberculin reactor testing (caudal fold test [CFT] alone, or CFT followed by comparative cervical test [CCT] or single intradermal comparative tuberculin test [SICTT]), antibody kits or ELISA (Level 5), or PCR without discriminatory typing (Level 3). Reported animal-level reactor proportions ranged from approximately 1.2% to 33.7% and are not directly comparable across tests. Species-level confirmation (Level 1–2) was achieved in only a small number of studies and repeatedly identified M. orygis in cattle and in at least seven captive wildlife species, together with captive monkeys, using RD typing, spoligotyping, MLVA, line-probe assay (LPA), and WGS. No study achieved culture-plus-discriminatory-molecular confirmation of M. bovis in any animal in Bangladesh; reported M. bovis "detections" rested on non-discriminatory PCR or serology. Human evidence was limited to three studies and one WGS-confirmed M. orygis patient. In Bangladesh, the only molecularly confirmed animal-adapted MTBC agent at the cattle–captive wildlife–human interface is M. orygis; existing M. bovis claims are not currently supported by discriminatory diagnostics and require cautious reinterpretation. zTB surveillance in Bangladesh should not be framed as an M. bovis-only problem. Species-level MTBC identification must be integrated into a staged, resource-appropriate One Health surveillance and control strategy spanning animals, wildlife, and humans.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.