广州北部山区并殖吸虫流行分布现状初步研究

Epidemic distribution of Paragonimus in northern suburban of Guangzhou

目的调查广州北部山区并殖吸虫流行分布现状。方法采集并解剖调查点山溪中螺蛳、溪蟹,检查并殖吸虫尾蚴、囊蚴。用所获囊蚴人工感染猫、犬,解剖猫、犬查找并殖吸虫成虫。取成虫样本,进行COI基因I、TS2基因序列分析,与GenBank检索并殖吸虫,COI基因与ITS2基因序列相比较。结果良口螺蛳尾蚴感染率0.32%(4/1 210),螺种为放逸短沟蜷。溪蟹囊蚴感染率100%(35/35)。感染度:79.4个囊蚴/只蟹,11.12个囊蚴/g蟹,最高只蟹检出囊蚴1 050个,蟹种平和华溪蟹。南昆山螺蛳尾蚴感染率0.15%(3/2 000),螺种为放逸短沟蜷。溪蟹囊蚴感染率100%(59/59),感染度:105.66个/只蟹,7.87个/g蟹。蟹种为平和华溪蟹。吕田螺蛳尾蚴感染率0.03%(1/310),螺蛳种为拟钉螺。溪蟹囊蚴感染率36.73%(36/98),感染度4.55个囊蚴/只蟹,0.53个囊蚴/g蟹,蟹种为平远南海溪蟹。良口和南昆山成虫COII、TS2基因DNA序列与GenBank检索卫氏并殖吸虫COII、TS2基因序列相比较:同源性分别为99%、98%和98%、97%。结论广州北部山区新发现卫氏并殖吸虫超高度疫源地两处,两疫源地虫种无差异。斯氏狸殖吸虫中度疫源地一处。

In order to investigate the distribution of Paragonimus in northern suburban of Guangzhou,snails and crabs were collected from mountain streams and the cercariae and metacercariae of Paragonimus were detected and dissected.Cats and dogs were artificially infected with the metacercariae of Paragonimus from infected crabs,as results,the adult worms of Paragonimus were detected from these cats and dogs.The COI and ITS2 sequence analysis were performed in the adult worm samples,and the sequence results were compared with those of Paragonimus sequence in GenBank.It was found that for snail samples in Liangkou,Nankun Mountain and Lvtian areas,the average infection rates of cercariae were 0.32%（4/1,210）,0.15%（3/2,000） and 0.03%（1/310）.The snail species in both Liangkou and Nankun Mountain areas were identified as Semisulcospira libertine,while the snail species in Lvtian area was Tricula.;for crab samples in Liangkou area,the average infection rate of P.westermani metacercariae was 100%（35/35）,and the crab species were identified as Sinopotamon pinheense.The average numbers of the metacercariae in per crab and per gram of crab were 79.4 and 11.12,respectively.The highest numbers of metacercariae in one crab was 1 050.And for crab samples in Nankun Mountain area,the average infection rate of P.westermani metacercariae was also 100%（59/59）,and the crab species were also identified as Sinopotamon pinheense.The average numbers of the metacercariae in per crab and per gram of crab were 105.66 and 7.87,respectively.For crab samples in Lvtian area,the average infection rate of Pagumogonimus skrjabini was 36.73%（36/98）,and the crab species were identified as Nanhaipotomon pinyuanense.The average numbers of the metacercariae in per crab and per gram of crab were 4.55 and 0.53,respectively.The DNA sequences for COI and ITS2 from the adult worms of P.westermani from the Liangkou and Nankun Mountain areas detected 99%,98% and 98%,97% homologous with those of P.westermani in the GenBank DNA database.There are two ultrahigh infectious focus of P.westermani found in northern suburban Guangzhou,and one moderate infectious focus of Pagumogonimus skrjabini.