Wolfson Wellcome Biomedical Laboratories, Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK.
Acta Trop. 2013 Nov;128(2):250-60. doi: 10.1016/j.actatropica.2012.08.009. Epub 2012 Aug 19.
Schistosoma mansoni is a widespread human helminth and causes intestinal schistosomiasis in 54 countries, mainly across Africa but also in Madagascar, the Arabian Peninsula and the neotropics. The geographical range of this parasite relies on the distribution of certain species of freshwater pulmonate snails of the genus Biomphalaria. Whilst S. mansoni is known to exhibit high population diversity the true extent of this diversity is still to be fully elucidated as sampling of this taxon progressively accrues. Here a DNA 'barcoding' approach is taken using sequence analysis of a 450bp region within the mitochondrial cox1 gene to assess the genetic diversity within a large number of S. mansoni larval stages collected from their natural human hosts across sub-Saharan Africa. Five hundred and sixty one individual parasite samples were examined from 22 localities and 14 countries. Considerable within-species diversity was found with 120 unique haplotypes splitting geographically into five discrete lineages. The highest diversity was found in East Africa with samples forming three of the five lineages. Less diversity was found in the Far and Central Western regions of Africa with haplotypes from the New World showing a close affinity to the Far Western African S. mansoni populations supporting the hypothesis of a colonisation of South America via the West African slave trade. The data are discussed in relation to parasite diversity and disease epidemiology.
曼氏血吸虫是一种广泛分布的人类寄生虫，在 54 个国家引起肠道血吸虫病，主要分布在非洲，但也分布在马达加斯加、阿拉伯半岛和新热带地区。这种寄生虫的地理范围依赖于某些淡水肺螺科生物的分布，这些生物属于比马属。虽然曼氏血吸虫的种群多样性很高，但这种多样性的真实程度仍有待充分阐明，因为对该分类群的采样逐渐增加。在这里，采用了一种 DNA“条形码”方法，使用线粒体 cox1 基因内 450bp 区域的序列分析来评估从撒哈拉以南非洲的自然人类宿主中收集的大量曼氏血吸虫幼虫阶段的遗传多样性。从 22 个地点和 14 个国家检查了 561 个个体寄生虫样本。发现了相当大的种内多样性，有 120 个独特的单倍型，地理上分为五个离散的谱系。东非的多样性最高，有三个样本形成了五个谱系中的三个。非洲远西部和中部地区的多样性较少，来自新世界的单倍型与远西部非洲的曼氏血吸虫种群密切相关，这支持了通过西非奴隶贸易将南美洲殖民化的假说。数据是根据寄生虫多样性和疾病流行病学进行讨论的。
