Molecular phylogeographic studies on Paragonimus westermani in Asia

The lung fluke, Paragonimus westermani (Kerbert, 1878), is widely distribut ed in Asia, and exhibits much variation in its biological properties. Previ ous phylogenetic studies using DNA sequences have demonstrated that samples from north-east Asia form a tight group distinct from samples from south A sia (Philippines, Thailand, Malaysia). Among countries from the latter regi on, considerable molecular diversity was observed. This was investigated fu rther using additional DNA sequences (partial mitochondrial cytochrome c ox idase subunit 1 (COI) and the second internal transcribed spacer of the nuc lear ribosomal gene repeat (ITS2)) from additional samples of P. westermani . Phylogenies inferred from these again found three or four groups within P . westermani, depending on the method of analysis. Populations of P. wester mani from north-east Asia use snail hosts of the family Pleuroceridae and d iffer in other biological properties from populations in south Asia (that u se snail hosts of the family Thiaridae). It is considered that the populati ons we sampled can be divided into two species, one in north-east Asia and the other in south Asia.