2011 Fiscal Year Final Research Report
Speciation of Taeniid cestodes (Echinococcus spp. and Taenia spp.) in the world and co-evolution of the host-parasite relationship
| Project/Area Number |
21256003
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Parasitology (including Sanitary zoology)
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| Research Institution | Asahikawa Medical College |
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Principal Investigator |
ITO Akira 旭川医科大学, 医学部, 教授 (70054020)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAO Minoru 旭川医科大学, 医学部, 准教授 (70155670)
NAKAYA Kazuhiro 旭川医科大学, 医学部, 准教授 (70109388)
SAKO Yasuhito 旭川医科大学, 医学部, 講師 (40312459)
YANAGIDA Tetsuya 旭川医科大学, 医学部, 助教 (40431837)
OKAMOTO Munehiro 京都大学, 霊長類研究所, 教授 (70177096)
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| Project Period (FY) |
2009 – 2011
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| Keywords | 感染症 / 遺伝子 |
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| Research Abstract |
Parasitic cestodes, Cestoda, Plathelminthes, have well been known to be hermatophroditic. Self-fertilization is the basic strategy for reproduction biology in cestodes. However, through our most recent studies on mitochondrial (haploid) and nuclear (diploid) DNA of two independent species infecting humans, Taenia saginata and Taenia asiatica have revealed that there are hybrids or hybrid derived adult tapeworms in Thailand and China where these species are sympatrically distributed. These data strongly reveal cross fertilization in the definitive host, humans, and launch “What is T. asiatica? Is it really independent species?" It is still under debates. Similar evidence showing cross fertilization between the intraspecies two, Asian and Afro/American genotypes of Taenia solium has been confirmed from larval stage of this parasite sampled in Madagascar. In Madagascar, we could have confirmed that the two genotypes are sympatrically distributed and also some hybrid individuals have been confirmed. Our work is the first one comparing both mitochondrial and nuclear genes in cestodes or platyhelminthes. These all data strongly suggest the cross fertilization in cestode reproduction biology. Molecular studies on Echinococcus spp. have also revealed that E. granulosus sensu lato is not a single species but 5 species, and a total of 9 independent species are included in the genus Echinococcus. Among these species, E. multilocularis is highly pathogenic and 3 (North American, Asian and European) genotypes have been known, but we have confirmed additional one, Mongolian genotype. The new information on the cestode speciation and identification has successfully been confirmed by the establishment of immuno- and molecular-diagnostic tools developed by our research team.
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[Journal Article] Usefulness of pumpkin seeds combined with areca nut extract in community-based treatment of human taeniasis in northwest Sichuan province2012
Author(s)
Li T, Ito A, Chen X, Long C, Okamoto M, Raoul F, Giraudoux P, Yanagida T, Nakao M, Xiao N,Craig PS
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Journal Title
Acta Trop
Volume: 124
Pages: 152-157
DOI
Peer Reviewed
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[Journal Article] A Loop-mediated isothermal amplification method for a differential identification of Taenia tapeworms from human: application to a field survey2012
Author(s)
Nkouawa A, Sako Y, Li T, Chen X, Nakao M, Yanagida T, Okamoto M, Giraudoux P, Raoul F, Nakaya K, Xiao N, Qiu J, Qiu D, Craig PS, Ito A.
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Journal Title
Parasitol Int
Volume: 61
Pages: 723-725
DOI
Peer Reviewed
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[Journal Article] Recent hybridization between Taenia asiatica and Taenia saginata2012
Author(s)
Yamane K, Suzuki Y, Tachi E, Li TY, Chen XW, Nakao M, Nkouawa A, Yanagida T, Sako Y, Ito A, Sato H, Okamoto M.
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Journal Title
Parasitol Int
Volume: 61
Pages: 351-355
DOI
Peer Reviewed
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