Králová-Hromadová Ivica, Čisovská Bazsalovicsová Eva, Radačovská Alžbeta, Šoltys Katarína, Juhásová Ľudmila, Minárik Gabriel, Kuchta Roman, Skírnisson Karl, Karlsbakk Egil, Štefka Jan
Institute of Parasitology, Slovak Academy of Sciences, Hlinkova 3, 04001 Košice, Slovakia.
Department of Microbiology and Virology, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 84215 Bratislava, Slovakia.
Int J Parasitol. 2025 May;55(6):281-298. doi: 10.1016/j.ijpara.2025.01.002. Epub 2025 Jan 10.
The diphyllobothriid tapeworm Dibothriocephalus dendriticus, one of the causative agents of the fish-borne zoonosis dibothriocephalosis, is mainly distributed in the Arctic/subarctic and temperate zones of the Northern Hemisphere (Europe, North America, and Asia), but also in the southern cone region of South America (Patagonia). The genetic structure and gene flow among 589 individuals of D. dendriticus, representing 20 populations, were studied using the mitochondrial cox1 gene as the first choice marker and 10 polymorphic nuclear microsatellite loci as a dominant molecular tool. The haplotype network of 30 cox1 haplotypes and Principal Coordinate Analysis/Structure analysis based on microsatellite data revealed close genetic relationships among populations within continents, namely northern and northwestern Europe (Norway, Finland, and UK/Scotland), North America (USA/Alaska, USA/Oregon, and Greenland), and South America (Argentina and Chile). The population from Iceland, located on the Mid-Atlantic Ridge between North America and Europe, was related to both Europe and North America. The mixed Nearctic and Palaearctic origin of D. dendriticus in Iceland was confirmed by a coalescent-based analysis of the microsatellite loci (in Migrate software). The most likely scenarios suggested that the Icelandic population is a genetic admixture of tapeworms from northwestern Europe and USA/Alaska. These findings corresponded with the distribution and migratory routes of piscivorous birds of the family Laridae, the main definitive hosts of D. dendriticus. The origin of an apparently non-native population of D. dendriticus in Patagonia was investigated in detail. The two most plausible hypotheses based on Migrate analysis represented different scenarios. One of them points to a European origin of the Patagonian population, the other to a North American origin. Future research with more extensive and a geographically broader sampling set is recommended to trace dispersal routes of D. dendriticus in Patagonia.
裂头绦虫属的树枝状双槽绦虫（Dibothriocephalus dendriticus）是食源性人畜共患疾病裂头绦虫病的病原体之一，主要分布于北半球的北极/亚北极和温带地区（欧洲、北美和亚洲），但在南美洲的南锥体地区（巴塔哥尼亚）也有分布。本研究以线粒体细胞色素氧化酶亚基I（cox1）基因作为首选标记，以10个多态性核微卫星位点作为主要分子工具，对代表20个种群的589条树枝状双槽绦虫个体的遗传结构和基因流进行了研究。基于30个cox1单倍型构建的单倍型网络以及基于微卫星数据的主坐标分析/结构分析显示，各大洲内的种群之间存在密切的遗传关系，即北欧和西北欧（挪威、芬兰以及英国/苏格兰）、北美（美国/阿拉斯加、美国/俄勒冈以及格陵兰）以及南美（阿根廷和智利）。位于北美和欧洲之间的大西洋中脊上的冰岛种群与欧洲和北美均有关联。通过对微卫星位点进行基于溯祖理论的分析（在Migrate软件中），证实了冰岛树枝状双槽绦虫具有近北极和古北极混合起源。最有可能的情况表明，冰岛种群是来自欧洲西北部和美国/阿拉斯加的绦虫的遗传混合体。这些发现与树枝状双槽绦虫的主要终末宿主——鸥科食鱼鸟类的分布和迁徙路线相一致。本研究还详细调查了巴塔哥尼亚地区一个明显的非本地树枝状双槽绦虫种群的起源。基于Migrate分析的两种最合理假设代表了不同的情况。其中一种假设认为巴塔哥尼亚种群起源于欧洲，另一种假设则认为其起源于北美。建议未来开展更广泛、地理范围更广的采样研究，以追踪树枝状双槽绦虫在巴塔哥尼亚的传播路线。
