Human diphyllobothriasis is a parasitic disease caused by ingestion of larvae (plerocercoids) in raw or undercooked fish and commonly found in temperate areas. Rare cases were reported in tropical or subtropical areas especially in children. The first documented case of pediatric diphyllobothriasis in Taiwan had been reported 11 years ago. Here, we report another 8-year-old girl case who presented with a live noodle-like worm hanging down from her anus, with no other detectable symptoms. We pulled the worm out and found the strobila being 260 cm in length. Examination of gravid proglottids showed that they were wider than their lengths, containing an ovoid cirrus sac in the anterior side and the rosette-shaped uterus. Eggs extracted from the uterus were ovoid and operculated. Diphyllobothrium latum was confirmed by molecular analysis of the mitochondrial DNA cytochrome c oxidase subunit 1 (cox1) gene. The girl was treated with a single oral dose of praziquantel, and no eggs or proglottids were observed from her stool in the subsequent 3 months. The reemergence of human diphyllobothriasis in non-endemic countries is probably due to prevalent habit of eating imported raw fish from endemic areas. This pediatric case raised our concern that human diphyllobothriasis is likely underestimated because of unremarkable symptoms.
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Human diphyllobothriosis in Taiwan: A review of cases and molecular evidence of Dibothriocephalus nihonkaiensis Chia-Kwung Fan, Daniel Barčák, Tomáš Scholz, Pasaikou Sonko, Martina Orosová, Kua-Eyre Su, Chun-Chao Chang, Yuarn-Jang Lee, Roman Kuchta, Mikuláš Oros Food and Waterborne Parasitology.2023; 33: e00213. CrossRef
We described 4 human infection cases of zoonotic fish-tapeworm, Diphyllobothrium nihonkaiense, identified with morphological and molecular characters and briefly reviewed Chinese cases in consideration of it as an emerging parasitic disease in China. The scolex and mature and gravid proglottids of some cases were seen, a rosette-shaped uterus was observed in the middle of the mature and gravid proglottids, and the diphyllobothriid eggs were yellowish-brown in color and displayed a small knob or abopercular protuberance on the opposite end of a lid-like opening. The average size of the eggs was recorded as 62-67×42-45 μm. The parasitic materials gathered from 4 human cases were morphologically identified as belonging to the genera Diphyllobothrium and Adenocephalus. The phylogenetic analysis based on the nucleotide sequences of cytochrome c oxidase subunit 1 gene of the etiologic agents confirmed that the 4 cases were D. nihonkaiense infection. The finding of 4 additional D. nihonkaiense cases suggests that D. nihonkaiense might be a major causative species of human diphyllobothriasis in China. A combined morphological and molecular analysis is the main method to confirm D. nihonkaiense infection.
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Dietary footprints of a global parasite: diagnosing Dibothriocephalus nihonkaiensis in non-endemic regions Wilson G.W. Goh, Jean-Marc Chavatte, Gabriel Z.R. Yan, Yuan Yi Constance Chen, Mark Dhinesh Muthiah, Lionel H.W. Lum Gut Pathogens.2025;[Epub] CrossRef
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Molecular Identification of Dibothriocephalus nihonkaiense Infection Using Nanopore Sequencing: A Case Report and Literature Review Hin-Fung Tsang, Stanley W.M. Leung, Tin-Nok Hung, Icy Law, Ka-Wai Lam, Loiston Chan, Sze-Chuen Cesar Wong Diagnostics.2024; 14(24): 2871. CrossRef
Human diphyllobothriosis in Taiwan: A review of cases and molecular evidence of Dibothriocephalus nihonkaiensis Chia-Kwung Fan, Daniel Barčák, Tomáš Scholz, Pasaikou Sonko, Martina Orosová, Kua-Eyre Su, Chun-Chao Chang, Yuarn-Jang Lee, Roman Kuchta, Mikuláš Oros Food and Waterborne Parasitology.2023; 33: e00213. CrossRef
Global analysis of cytochrome c oxidase subunit 1 (cox1) gene variation in Dibothriocephalus nihonkaiensis (Cestoda: Diphyllobothriidae) Niichiro Abe, Takashi Baba, Yoshitaka Nakamura, Shintaro Murakami Current Research in Parasitology & Vector-Borne Diseases.2021; 1: 100042. CrossRef
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