Investigation On Pomacea Canaliculata Infected By Angiostrongylus Cantonensis In Two States Of Yunnan Province And Phylogenetic Analysis

【Objective】To investigate the snails infection which is the intermediate host of Angiostrongylus cantonensis in Xishuangbanna and Dehong in Yunnan province. And explore the gene Phylogenetic of Angiostrongylus cantonensis.【Method】We used regional sampling, extracted 4 counties in Xishuangbanna and Dehong to investigate the Pomacea canaliculata and Cipangopaludina cathayensis infected with Angiostrongylus cantonensis.The Pomacea canaliculata and Cipangopaludina cathayensis were handed by Lung screening method and enzyme-digestion method,and their larvaes were collected. The DNA of Angiostrongylus cantonensis isolated from Xishuangbanna and Dehong were extracted: PCR amplified of two counties of themitochondria DNA Cytochrome coxidase subunit I(COI) gene fragments were cloned and sequenced; Calculating genetic distance, phylogenetic,comparative angiostrongylus genetic relationship about two counties of Yunnan province.【Result】5139Pomacea canaliculata were collected from 4 counties in Xishuangbanna and Dehong. Among them we have not detected the Guangzhou angiostrongylus cantonensis larvae in Cipangopaludina cathayensis. The positive Pomacea canaliculata for twenty-nine and the total positive rate of Pomacea canaliculata was0.56%. The infection rate was 0.98%( 14/1428) and 0.28%( 3/1070) in Xishuangbanna Mengla and Jinghong; The infection rate was 1.10%(10/905) and0.12%(2/1736) in Dehong Ruili and Longchuan. In different growth environment the Pomacea canaliculata infection rates are also different, The highest infection rate was1.37%(23/1683)for ditch type, followed by paddy fields type and fish ponds type,the infection rate was 0.17%(4/2398) and 0.19%(2/1058)respectly. Dehong and Xishuangbanna 、 Dehong and Baxi standard 、 Dehong and Fujian standard Angiostrongylus cantonensis COIgene sequence homology were 93%、98%and 99%; Xishuangbanna and Baxi standard 、 Xishuangbanna and Fujian standard Angiostrongylus cantonensis COI gene sequences homology were 92% and93%; Baxistandard and Fujian standard Angiostrongylus cantonensis COI gene sequence homology was 97%.It Showed that Xishuangbanna and Dehong in Yunnan provinces of Angiostrongylus cantonensis COI gene highly homologous, they and Baxistandard and Fujian standard strains belong to the same insect species.【Conclusion】For investige the snails infection which is the intermediate host of Angiostrongylus cantonensisin two places,we can known that each survey point can captured the live Pomacea canaliculata and Cipangopaludina cathayensis from the field. The natural foci of Pomacea canaliculataare mainly distributed in eight villages and towns(Mengman、Mengbang、Mengla、Jingha、Jiexiang、Nongdao、Chengzi、Longba). Infection rates of Pomacea canaliculata in Xishuangbanna and Dehong of Yunnan provinces were different, the high or low infection rate was relative to Pomacea canaliculata Living environmental factors and the eating habits of the people,so there is a potential threat to human infection;Four methods was used to construct phylogenetic tree topology are basically identical. That showed Xishuangbanna and Dehong in Yunnan provinces of Angiostrongylus cantonensis COI gene highly homologous, they and Baxi and Fujian standard strains belong to the same insect species.