Molecular epidemiology of bovine tuberculosis in Northern Ghana identifies several uncharacterized bovine spoligotypes and suggests possible zoonotic transmission

PLoS Negl Trop Dis. 2022 Aug 11;16(8):e0010649. doi: 10.1371/journal.pntd.0010649. eCollection 2022 Aug.

Abstract

Objective: We conducted an abattoir-based cross-sectional study in the five administrative regions of Northern Ghana to determine the distribution of bovine tuberculosis (BTB) among slaughtered carcasses and identify the possibility of zoonotic transmission.

Methods: Direct smear microscopy was done on 438 tuberculosis-like lesions from selected cattle organs and cultured on Lowenstein-Jensen media. Acid-fast bacilli (AFB) isolates were confirmed as members of the Mycobacterium tuberculosis complex (MTBC) by PCR amplification of IS6110 and rpoß. Characterization and assignment into MTBC lineage and sub-lineage were done by spoligotyping, with the aid of the SITVIT2, miruvntrplus and mbovis.org databases. Spoligotype data was compared to that of clinical M. bovis isolates from the same regions to identify similarities.

Results: A total of 319/438 (72.8%) lesion homogenates were smear positive out of which, 84.6% (270/319) had microscopic grade of at least 1+ for AFB. Two hundred and sixty-five samples (265/438; 60.5%) were culture positive, of which 212 (80.0%) were MTBC. Approximately 16.7% (34/203) of the isolates with correctly defined spoligotypes were negative for IS6110 PCR but were confirmed by rpoß. Spoligotyping characterized 203 isolates as M. bovis (198, 97.5%), M. caprae (3, 1.5%), M. tuberculosis (Mtbss) lineage (L) 4 Cameroon sub-lineage, (1, 0.5%), and M. africanum (Maf) L6 (1, 0.5%). A total of 53 unique spoligotype patterns were identified across the five administrative regions (33 and 28 were identified as orphan respectively by the SITVIT2 and mbovis.org databases), with the most dominant spoligotype being SIT1037/ SB0944 (77/203, 37.93%). Analysis of the bovine and human M. bovis isolates showed 75% (3/4) human M. bovis isolates sharing the same spoligotype pattern with the bovine isolates.

Conclusion: Our study identified that approximately 29% of M. bovis strains causing BTB in Northern Ghana are caused by uncharacterized spoligotypes. Our findings suggest possible zoonotic transmission and highlight the need for BTB disease control in Northern Ghana.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Typing Techniques
  • Cattle
  • Cross-Sectional Studies
  • Ghana / epidemiology
  • Humans
  • Molecular Epidemiology
  • Mycobacterium bovis* / genetics
  • Mycobacterium tuberculosis* / genetics
  • Tuberculosis* / epidemiology
  • Tuberculosis* / microbiology
  • Tuberculosis* / veterinary
  • Tuberculosis, Bovine* / epidemiology
  • Tuberculosis, Bovine* / microbiology

Grants and funding

DYM and RK are part of The Pan-African Network for Rapid Research, Response, Relief and Preparedness for Infectious Diseases Epidemics (PANDORA-ID-NET) Consortium (https://www.pandora-id.net/) funded by EDCTP Reg/Grant RIA2016E-1609 from the European and Developing Countries Clinical Trials Partnership (EDCTP2) programme, which is supported under Horizon 2020, the European Union’s Framework Programme for Research and Innovation. DYM is a GSK-EDCTP Senior Fellow (TMA.2017.GSF.1942-TB-DM). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.