Investigation On Epidemic Focus Of Paragonimiasis In Sangyan District,Fujian Province And Study On The Independence Of Pagumogonimus Veocularis

Objective: To study the disposition of epidemic focus and species of Paragonimiasis and infection condition of people, and the independence of P.veocularis by morphous observation and molecular technique. Methods: Epidemiological investigation were used to study Paragonimiasis in Sangyan district by routine methods. Metacercariae and cercariae of Paragonimus were examined and observed about snails and crabs in Sangyan district. DNA of metacercariae of P.skrjabini and Pveocularis were extracted. These DNA sequences were obtained from the ITS2 genes used PCR amplification with special primer, then comparing these gene identities with Blast program of GenBank. Phylogenetic trees were built from the results using ME program of MEGA3.0 software. Results: Cercariae of Paragonimus was not found in 654 Semisulcospira liberlina,468 Erichi sp.nov and 235 Assimili examined. Sinoptamon fujianense, Malaypotamon fukienense and Nanhaipotamon angulatum served as the second intermediate host harboured metacercariae of Paragonimus.Infection rate of which was 44.28%(62/140) with an average number of 11.03 metacercariae per crab and 1.24 per gram of crab tissues. So, infestation index of metacercariae was 6.07.Eggs of Paragonimus were checked from 2 dejectas of wild cats. The positive rate of skin test in people was 8.64%(21/243). The positive rate of Paragonimiasis antibody of positive people of skin test was 23.81%(5/21). Above all, Sangyan district is a severely endemic areas of Paragonimiasis as the most of P.skrjabini.There were obvious morphological differences between metacercariae of P.skrjabini and Pveocularis,but it was observed that 57.14% (12/21) of metarcercariae of Pveocularis separated from crabs in 0.5~2h changed into analogous metacercariae of P.skrjabini in morphological character. Gene identities comparison indicates: The identity of ITS2 gene between Pveocularis and P.skrjabini is 100%,and the basyl variation number of ITS2 gene between Pveocularis and P.skrjabini is 0. So they have not gene variation; The identities of ITS2 gene among Pveocularis and P.westermani,E.cenocopiosus.P.macrorchis are 90%,93% and 92% respectively. The basyl variation number of ITS2 gene among P.veocularis and Pwestermani.E.cenocopiosus, P.macrorchis are 33,25 and 29 respectively. So they have very obvious gene variation. Phylogenetic tree indicates:P. skrjabini and P.veocularis lie at the same position, but they are great further with P.macrorchis, Euparagonimus cenocopiosus and P.westermani. Conclusion: Sangyan district is a severely endemic area of Paragonimiasis as the most of P.skrjabini. Morphologic characteristics among metacercariae of P.skrjabini and P.veocularis were obviously different. But 57.14% ( 12/21 ) of metacercariae of P.veocularis separated from crabs in 0.5~2h changed into analogous metacercariae of P.skrjabini in morphological character.ITS2 genes of P.skrjabini and P.veocularis were high identities according to the gene identical analysis, and they have no obvious phylogenetic distances in the phylogenetic tree. Above all, P.skrjabini and P.veocularis are the same species. P.veocularis is not separate species.