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Multiple Introductions and Recent Spread of the Emerging Human Pathogen Mycobacterium ulcerans across AfricaVandelannoote, K., Meehan, Conor J., Eddyani, M., Affolabi, D., Phanzu, D.M., Eyangoh, S., Jordaens, K., Portaels, F., Mangas, K., Seemann, T., Marsollier, L., Marion, E., Chauty, A., Landier, J., Fontanet, A., Leirs, H., Stinear, T.P., de Jong, B.C. 24 September 2019 (has links)
Yes / Buruli ulcer (BU) is an insidious neglected tropical disease. Cases are reported around the world but the rural regions of West and
Central Africa are most affected. How BU is transmitted and spreads has remained a mystery, even though the causative agent,
Mycobacterium ulcerans, has been known for more than 70 years. Here, using the tools of population genomics, we reconstruct the
evolutionaryhistoryofM. ulceransbycomparing165isolatesspanning48yearsandrepresenting11endemiccountriesacrossAfrica.
The genetic diversity of African M. ulcerans was found to be restricted due to the bacterium’s slow substitution rate coupled with its
relatively recent origin. We identified two specific M. ulcerans lineages within the African continent, and inferred that M. ulcerans
lineage Mu_A1 existed in Africa for several hundreds of years, unlike lineage Mu_A2, which was introduced much more recently,
approximately during the 19th century. Additionally, we observed that specific M. ulcerans epidemic Mu_A1 clones were introduced
during the same time period in the three hydrological basins that were well covered in our panel. The estimated time span of the
introduction events coincides with the Neo-imperialism period, during which time the European colonial powers divided the African
continent among themselves. Using this temporal association, and in the absence of a known BU reservoir or—vector on the
continent, we postulate that the so-called "Scramble for Africa" played a significant role in the spread of the disease across the
continent. / K.V. was supported by a PhD-grant of the Flemish Interuniversity Council—University Development Cooperation (Belgium). B.d.J. and C.M. were supported by the European Research Council-INTERRUPTB starting grant (no. 311725). T.P.S. was supported by a fellowship from the National Health and Medical Research Council of Australia (1105525). Funding for this work was provided by the Department of Economy, Science and Innovation of the Flemish Government, the Stop Buruli Consortium supported by the UBS Optimus Foundation, and the Fund for Scientific Research Flanders (Belgium) (FWO grant no. G.0321.07N). The computational resources used in this work were provided by the HPC core facility CalcUA and VSC (Flemish Supercomputer Center), funded by the University of Antwerp, the Hercules Foundation and the Flemish Government—department EWI. Aspects of the research in Cameroon and Benin were funded by the Raoul Follereau Fondation France.
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Mycobacterium ulcerans Population Genomics to Inform on the Spread of Buruli Ulcer across Central AfricaVandelannoote, K., Phanzy, D.M., Kibadi, K., Eddyani, M., Meehan, Conor J., Jordaens, K., Leirs, H., Portaels, F., Stinear, T.P., Harris, S.R., de Jong, B.C. 10 September 2019 (has links)
Yes / Buruli ulcer is a neglected tropical disease of skin and subcutaneous tissue caused by infection with the pathogen Mycobacterium ulcerans. Many critical issues for disease control, such as understanding the mode of transmission and identifying source reservoirs of M. ulcerans, are still largely unknown. Here, we used genomics to reconstruct in detail the evolutionary trajectory and dynamics of M. ulcerans populations at a central African scale and at smaller geographical village scales. Whole-genome sequencing (WGS) data were analyzed from 179 M. ulcerans strains isolated from all Buruli ulcer foci in the Democratic Republic of the Congo, The Republic of Congo, and Angola that have ever yielded positive M. ulcerans cultures. We used both temporal associations and the study of the mycobacterial demographic history to estimate the contribution of humans as a reservoir in Buruli ulcer transmission. Our phylogeographic analysis revealed one almost exclusively predominant sublineage of M. ulcerans that arose in Central Africa and proliferated in its different regions of endemicity during the Age of Discovery. We observed how the best sampled endemic hot spot, the Songololo territory, became an area of endemicity while the region was being colonized by Belgium (1880s). We furthermore identified temporal parallels between the observed past population fluxes of M. ulcerans from the Songololo territory and the timing of health policy changes toward control of the Buruli ulcer epidemic in that region. These findings suggest that an intervention based on detecting and treating human cases in an area of endemicity might be sufficient to break disease transmission chains, irrespective of other reservoirs of the bacterium.
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