Vandelannoote Koen, Meehan Conor J, Eddyani Miriam, Affolabi Dissou, Phanzu Delphin Mavinga, Eyangoh Sara, Jordaens Kurt, Portaels Françoise, Mangas Kirstie, Seemann Torsten, Marsollier Laurent, Marion Estelle, Chauty Annick, Landier Jordi, Fontanet Arnaud, Leirs Herwig, Stinear Timothy P, de Jong Bouke C
Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
Evolutionary Ecology Group University of Antwerp, Antwerp, Belgium.
Genome Biol Evol. 2017 Mar 1;9(3):414-426. doi: 10.1093/gbe/evx003.
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 evolutionary history of M. ulcerans by comparing 165 isolates spanning 48 years and representing 11 endemic countries across Africa. 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.
布氏杆菌溃疡（BU）是一种隐匿性被忽视的热带病。世界各地均有病例报告，但西非和中非农村地区受影响最为严重。尽管致病病原体溃疡分枝杆菌已被发现70多年，但布氏杆菌溃疡如何传播和扩散仍是个谜。在此，我们运用群体基因组学工具，通过比较跨越48年、代表非洲11个流行国家的165株分离株，重建了溃疡分枝杆菌的进化史。由于该细菌的替换率缓慢且起源相对较近，非洲溃疡分枝杆菌的遗传多样性受到限制。我们在非洲大陆内鉴定出两个特定的溃疡分枝杆菌谱系，并推断溃疡分枝杆菌谱系Mu_A1在非洲已存在数百年，而谱系Mu_A2则是在更近的时期，大约19世纪才传入。此外，我们观察到在我们研究范围内覆盖良好的三个水文流域，特定的溃疡分枝杆菌流行Mu_A1克隆在同一时期被引入。引入事件的估计时间跨度与新帝国主义时期相符，在此期间欧洲殖民列强瓜分了非洲大陆。利用这种时间关联，且鉴于非洲大陆不存在已知的布氏杆菌溃疡宿主或传播媒介，我们推测所谓的“非洲争夺战”在该疾病在非洲大陆的传播中起到了重要作用。
