Molecular Genetics in Paragonimus westermani Complex in Asia

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The present studies are to deduce (1) the origin of the triploids of Paragonimus westermani of Japan and (2) what P.westermani is which was described by Curbert in 1878, in the course of the studies on the biology, genetic variation and speciation inP.westermani Complex in Asia. More than 3,000 Paragonimus metacercariae were isolated from about 3,000 crayfishes, Cambaroides dauricus collected in Liaoning Province of north-eastern China in 1995. They were identified as P.westermani based on metacercarial morphology as well as that of the adults obtained from the experimentally infected dogs and cats. The flukes were proved to be diploid, triploid and tetraploid types. The triploid fluke from China was almost the same as Japanese one not only in host-specificity but also in electrophoretic patterns. In the diploid fluke, Chinese populations were polymorphic in electrophoretic patterns, while Japanese ones were monomorphic. The specific alleles of Japanese triploid were found, with high f … More requency, in the diploid populations in China. Therefore, a certain diploid population of this fluke in north-eastern China seems to be related to the ancestor of Japanese triploid in terms of the gene introgression. Ninety-seven Paragonimus metacercariae were isolated from 239 freshwater crabs, Potamiscus manipurensis collected in Manipur, north-eastern India in 1995. They were provisionally classified into 4 groups : westermani, bangkokensis, heterotremus and excysted types. They were inoculated into dogs, cats and a fellet. The morphology of the adults obtained from experimentally infected dogs with westermani type metacercariae was in good agreement with the description of P.westermani by Vevers (1923), but not Curbert (1878). About 300 Paragonimus metacercariae were isolated from 300 freshwater crabs, Phricotelphusa aedes collected in southern Theiland in 1996. They were classified into 2 groups and inoculated into dogs, cats and albino rats.Further studies on these flukes are now in progress. Less