Epidemiological survey and phylogenetic analysis of Paragonimus westermani isolates in Jinhua, China
Paragonimiasis has previously been reported in many zones of China, which is the infestation of the trematode genus Paragonimus. The aim of this study was to investigate the presence and epidemiology of paragonimiasis in Jinhua which is next to Fujian, China. The differences of Paragonimus westmani isolates from Jinhua and other areas of the world were also analyzed. Freshwater crabs and snails from streams located in each of the villages were dissected for isolation of Paragonimus metacercariae. The epidemiology data were further analyzed by using geographic information systems (GIS). We found that the infestation rate for the Paragonimus cercariae in snails was as low as 2.3%, while that was as high as 76.67% in crabs. So, freshwater crabs were demonstrated as one of the main hosts for P. metacercariae in Jinhua. Moreover, phylogenetic analysis indicated that the sequences of the second internal transcribed spacer (ITS2) and cytochrome coxidase subunit I (COI) were conserved among different isolates, especially for the ITS2 gene. Based on the phylogenetic trees generated from the comparison results of COI gene, it was interesting to find that Paragonimus strains from different areas were present in different cluster. We conclude that the COI gene of Paragonimus can be a molecular marker contributing to the typing and source tracking for Paragonimiasis.
Key words: Paragonimus westermani, epidemiological survey, second internal transcribed spacer (ITS2), cytochrome coxidase subunit I (COI) gene.