Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 BP 770, Abidjan 22, Côte d'Ivoire.
Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303, Abidjan 01, Côte d'Ivoire.
Parasit Vectors. 2019 Mar 19;12(1):117. doi: 10.1186/s13071-019-3381-3.
Accurate identification of schistosome species infecting intermediate host snails is important for understanding parasite transmission, schistosomiasis control and elimination. Cercariae emerging from infected snails cannot be precisely identified morphologically to the species level. We used molecular tools to clarify the distribution of the Schistosoma haematobium group species infecting bulinid snails in a large part of Côte d'Ivoire and confirmed the presence of interspecific hybrid schistosomes.
Between June 2016 and March 2017, Bulinus snails were sampled in 164 human-water contact sites from 22 villages of the northern and central parts of Côte d'Ivoire. Multi-locus genetic analysis (mitochondrial cox1 and nuclear ITS) was performed on individual schistosome cercariae shed from snails, in the morning and in the afternoon, for species and hybrid identification.
Overall, 1923 Bulinus truncatus, 255 Bulinus globosus and 1424 Bulinus forskalii were obtained. Among 2417 Bulinus screened, 25 specimens (18 B. truncatus and seven B. globosus) shed schistosomes, with up to 14% infection prevalence per site and time point. Globally, infection rates per time point ranged between 0.6 and 4%. Schistosoma bovis, S. haematobium and S. bovis × S. haematobium hybrids infected 0.5%, 0.2% and 0.4% of the snails screened, respectively. Schistosoma bovis and hybrids were more prevalent in B. truncatus, whereas S. haematobium and hybrid infections were more prevalent in B. globosus. Schistosoma bovis-infected Bulinus were predominantly found in northern sites, while S. haematobium and hybrid infected snails were mainly found in central parts of Côte d'Ivoire.
The data highlight the necessity of using molecular tools to identify and understand which schistosome species are transmitted by specific intermediate host snails. The study deepens our understanding of the epidemiology and transmission dynamics of S. haematobium and S. bovis in Côte d'Ivoire and provides the first conclusive evidence for the transmission of S. haematobium × S. bovis hybrids in this West African country. Trial registration ISRCTN, ISRCTN10926858. Registered 21 December 2016; retrospectively registered (see: http://www.isrctn.com/ISRCTN10926858 ).
准确识别感染中间宿主蜗牛的血吸虫种类对于了解寄生虫传播、血吸虫病控制和消除至关重要。从感染蜗牛中逸出的尾蚴在形态上无法精确鉴定到种的水平。我们使用分子工具来阐明科特迪瓦大部分地区感染扁卷螺的曼氏血吸虫组物种的分布，并证实了种间杂交血吸虫的存在。
2016 年 6 月至 2017 年 3 月，在科特迪瓦北部和中部的 22 个村庄的 164 个人与水接触点采集了扁卷螺。对从蜗牛上午和下午排出的单个血吸虫尾蚴进行了多基因座遗传分析（线粒体 cox1 和核 ITS），以鉴定种和杂交种。
共获得 1923 只布氏拟钉螺、255 只球形拟钉螺和 1424 只福氏拟钉螺。在筛选的 2417 只扁卷螺中，有 25 只（18 只布氏拟钉螺和 7 只球形拟钉螺）排出了血吸虫，每个地点和时间点的感染率高达 14%。总体而言，每个时间点的感染率在 0.6%至 4%之间。感染的蜗牛分别有 0.5%、0.2%和 0.4%感染牛血吸虫、曼氏血吸虫和牛血吸 × 曼氏血吸虫杂种。牛血吸虫和杂种在布氏拟钉螺中更为普遍，而曼氏血吸虫和杂种感染在球形拟钉螺中更为普遍。感染牛血吸虫的布氏拟钉螺主要分布在北部地区，而感染曼氏血吸虫和杂种的蜗牛主要分布在科特迪瓦中部。
这些数据突出表明，有必要使用分子工具来识别和了解哪些血吸虫种由特定的中间宿主蜗牛传播。该研究加深了我们对科特迪瓦曼氏血吸虫和牛血吸虫的流行病学和传播动力学的理解，并为该西非国家传播曼氏血吸虫 × 牛血吸虫杂种提供了第一个确凿的证据。
ISRCTN，ISRCTN10926858。注册于 2016 年 12 月 21 日；回溯性注册（见：http://www.isrctn.com/ISRCTN10926858）。
