Abstract：
Human diphyllobothriasis, caused by Dibothriocephalus nihonkaiensis, is prevalent globally, especially in regions where raw fish is consumed. Recent molecular diagnostic techniques have made species identification of tapeworm parasites and the determination of genetic variations among parasite populations possible. However, only a few studies done over a decade ago, have reported on the genetic variation among D. nihonkaiensis in Japan. The present study employed PCR-based mitochondrial DNA analysis to specifically detect D. nihonkaiensis from archived clinical samples, and to determine any genetic variation that may exist among the Japanese broad tapeworms from patients of Kanagawa Prefecture, Japan. Target genes were amplified from DNA extracted from the ethanol- or formaldehyde-fixed samples by PCR. Further sequencing and comparative phylogenetic analyses based on mitochondrial COI and ND1 sequences were also performed. In our results, all PCR-amplified and sequenced samples were identified as D. nihonkaiensis. Analysis of COI sequences revealed two haplotype lineages. However, clustering of almost all COI (and ND1) sample sequences into one of the two haplotype clades, together with reference sequences from different countries worldwide, revealed a common haplotype among D. nihonkaiensis samples in our study. Our results suggest a possible presence of a dominant D. nihonkaiensis haplotype, with a global distribution circulating in Japan. Results from this study have the potential to improve the management of clinical cases and establish robust control measures to reduce the burden of human diphyllobothriasis in Japan.
摘要：
人类双叶病，由日本双头鱼引起，在全球普遍存在，尤其是在食用生鱼的地区。最近的分子诊断技术已经使tape虫寄生虫的物种鉴定和确定寄生虫种群之间的遗传变异成为可能。然而,十年前只做了几项研究，已经报道了日本日本D.nihonkaiensis的遗传变异。本研究采用基于PCR的线粒体DNA分析从存档的临床样品中特异性检测D.nihonkaiensis，并确定来自神奈川县患者的日本广泛tape虫之间可能存在的任何遗传变异，日本。通过PCR从提取自乙醇或甲醛固定样品的DNA扩增靶基因。还进行了基于线粒体COI和ND1序列的进一步测序和比较系统发育分析。在我们的结果中，所有PCR扩增和测序的样品均被鉴定为D.nihonkaiensis。COI序列的分析揭示了两个单倍型谱系。然而,将几乎所有COI（和ND1）样本序列聚类成两个单倍型进化枝之一，以及来自世界各地不同国家的参考序列，在我们的研究中揭示了日本D.nihonkaiensis样品中常见的单倍型。我们的结果表明可能存在显性D.nihonkaiensis单倍型，在日本流通的全球分布。这项研究的结果有可能改善临床病例的管理，并建立强有力的控制措施，以减轻日本人类二叶病的负担。
