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Diphyllobothriasis associated with eating raw pacific salmon
Naoki Arizono1, Minoru Yamada, Fukumi Nakamura-Uchiyama
1Kyoto Prefectural University of Medicine, Kyoto, Japan. arizonon@koto.kpu-m.ac.jp
Emerging Infectious Diseases
|June 16, 2009
Summary
Human infections with the broad tapeworm Diphyllobothrium nihonkaiense are rising globally, particularly in urban populations. This parasite, linked to salmon consumption, presents a growing public health concern.
Area of Science:
- Parasitology
- Infectious Diseases
- Epidemiology
Background:
- The broad tapeworm Diphyllobothrium nihonkaiense infection is increasing in urban areas of Japan and Europe.
- D. nihonkaiense is morphologically similar to D. latum but genetically distinct, using Pacific salmon as an intermediate host.
- Clinical signs include diarrhea and passage of long tapeworm segments (strobila).
Purpose of the Study:
- To investigate the changing epidemiology of Diphyllobothrium nihonkaiense infections.
- To understand the life cycle and geographic distribution of D. nihonkaiense.
- To identify the natural definitive host of D. nihonkaiense.
Main Methods:
- Review of recent clinical case data.
- Genetic analysis to distinguish D. nihonkaiense from D. latum.
- Ecological studies to determine host-parasite relationships.
Main Results:
- Infection incidence is increasing in urban populations worldwide.
- Pacific salmon are confirmed as the second intermediate host.
- Brown bears in the Pacific coast region are identified as the natural final host.
Conclusions:
- Diphyllobothrium nihonkaiense infections are shifting from rural to urban populations.
- The consumption of seafood, including salmon, is a key factor in transmission.
- Further research is needed to fully elucidate the tapeworm's life history and range.
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