Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Aug 21;17(1):64.
doi: 10.1186/s13099-025-00738-9.

Dietary footprints of a global parasite: diagnosing Dibothriocephalus nihonkaiensis in non-endemic regions

Wilson G W Goh  1 , Jean-Marc Chavatte  2 , Gabriel Z R Yan  3   2   4 , Yuan Yi Constance Chen  5 , Mark Dhinesh Muthiah  6 , Lionel H W Lum  3
Affiliations

Dietary footprints of a global parasite: diagnosing Dibothriocephalus nihonkaiensis in non-endemic regions

Wilson G W Goh et al. Gut Pathog. .

Abstract

Background: Species within the genus Dibothriocephalus/Diphyllobothrium are notable for being among the largest cestodes capable of human infection. Historically, Dibothriocephalus latus (previously Diphyllobothrium latus) is considered the more prevalent species (in Europe and Patagonia). However, Dibothriocephalus nihonkaiensis (previously Diphyllobothrium nihonkaiensis) is commonly found in East Asian countries, particularly Japan, where diets frequently include raw salmons. The increasing globalization and adoption of diverse dietary practices have led to the detection of tapeworm infections like D. nihonkaiensis outside their traditionally endemic areas, potentially making them more common than previously thought, as exemplified by the present case in Singapore.

Case presentation: A 35-year-old Chinese female presented with chronic abdominal distension, loose stools and unintentional weight loss. 3 months prior to her symptom onset, she had travelled extensively throughout Asia (Thailand, Vietnam, Laos, Malaysia and China) and Mexico and had consumed raw salmon throughout her travels. A full blood count revealed eosinophilia, and a worm was passed during bowel preparation. Molecular sequencing identified it as D. nihonkaiensis. She was treated successfully with praziquantel.

Conclusion: Increased globalization, cross-cultural dietary exchange, and greater salmon consumption have expanded the geographic distribution of D. nihonkaiensis infections beyond previously endemic regions. Consequently, clinicians worldwide must maintain a high index of suspicion for this parasitic infection, even in non-endemic areas. A thorough patient history, with particular attention to dietary habits and travel, is paramount for accurate and timely diagnosis, thereby enabling appropriate treatment and preventing potential complications. Increased awareness, reporting, and molecular identification of Dibothriocephalus are crucial for determining infection sources and guiding food safety surveillance.

Keywords: Dibothriocephalus; Diphyllobothrium; Abdominal distension; Cestodes; Eosinophilia; Praziquantel; Salmon consumption.

PubMed Disclaimer

Conflict of interest statement

Declarations. Ethics approval and consent to participate: Not applicable. Consent for publication: Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor of this journal. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
(A) Worm expelled from patient (B) Microphotograph of D. nihonkaiensis proglottids (width 5.4 mm x thickness 2.1 mm) with a uterus filled with eggs and genital pore (C) Iodine wet mount specimen of the egg from D. nihonkaiensis
See this image and copyright information in PMC

References

    1. Ikuno H, Akao S, Yamasaki H. Epidemiology of diphyllobothrium Nihonkaiense diphyllobothriasis, japan, 2001–2016. Emerg Infect Dis. 2018;24(8):1428–34. - PMC - PubMed
    1. Tsuboi M, Hayakawa K, Yamasaki H, Katanami Y, Yamamoto K, Kutsuna S, Takeshita N, Kanagawa S, Ohmagari N, Kato Y. Clinical characteristics and epidemiology of intestinal tapeworm infections over the last decade in tokyo, japan: A retrospective review. PLoS Negl Trop Dis. 2018;12(2):e0006297. - PMC - PubMed
    1. Le TH, Blair D, McManus DP. Mitochondrial genomes of parasitic flatworms. Trends Parasitol. 2002;18(5):206–13. - PubMed
    1. Park SH, Jeon HK, Kim JB. Four additional cases of diphyllobothrium Nihonkaiense infection confirmed by analysis of COX1 gene in Korea. Korean J Parasitol. 2015;53(1):105–8. - PMC - PubMed
    1. Chen S, Ai L, Zhang Y, Chen J, Zhang W, Li Y, Muto M, Morishima Y, Sugiyama H, Xu X, Zhou X, Yamasaki H. Molecular detection of Diphyllobothrium Nihonkaiense in humans. China Emerg Infect Dis. 2014;20(2):315–8. - PMC - PubMed

LinkOut - more resources