中缅边境(西段)传疟媒介的初步调查

Investigation on Malaria Vectors in Western Part of China-Myanmar Border

目的了解中缅边境(西段)传疟媒介的分布与构成。方法 2008年8～9月,在中缅边境的中国云南省盈江县及其相邻的缅甸昔懂县6个自然村,用诱蚊灯在人房和牛棚共进行20次通宵诱捕。将捕获的蚊虫以传统方法进行形态学鉴定,然后用复合PCR法鉴别微小按蚊、乌头按蚊和杰普按蚊。同时,抽提部分蚊虫标本总基因组DNA,以巢式PCR方法检测蚊体内的疟原虫感染情况。结果共捕获各类蚊虫4 571只,隶属9属50种,其中按蚊属是优势蚊种,占总量的54.32%(2 483/4 571)。人房和牛棚的按蚊蚊种构成差异有统计学意义,其中人房以腹簇按蚊、微小按蚊和中华按蚊为主,而牛棚以腹簇按蚊(223只)、环纹按蚊(184只)、迷走按蚊(131只)和杰普按蚊(129只)为主。对比有牛村和无牛村中人房的蚊种构成发现,有牛村的人房以微小按蚊(260只)和腹簇按蚊(49只)为主,而无牛村人房则以腹簇按蚊(481只)和中华按蚊(124只)为主。巢式PCR检测1 075只按蚊,其中9只检出疟原虫阳性,分别为微小按蚊(7/408)、乌头按蚊(1/125)和伪威氏按蚊(1/101)。经测序鉴定均为恶性疟原虫感染,目的条带长204 bp。结论中缅边境(西段)蚊虫密度高、种类多,在传疟作用中以微小按蚊最为重要,乌头按蚊和伪威氏按蚊亦为当地的传播媒介。

Objective To reveal the distribution and composition of malaria-transmitting vectors on the western part of China-Myanmar border.Methods An entomological survey of malaria vectors was carried out in six villages of Yingjiang County and Xidong County on China-Myanmar border between August and September,2008.Mosquitoes in human dwellings and cattle sheds were collected by overnight trapping with ovitrap light.The mosquitoes were firstly identified morphologically,and then Anopheles minimus A and C,An.aconitus,and An.jeyporiensis were identified by using multiplex PCR.Some mosquitoes were selected to extract the total genomic DNA,and detect sporozoites by nested PCR.Results A total of 4 571 mosquitoes were captured with 54.32%（2 483/4 571） of anopheline mosquitoes.There was significant difference in Anopheles species composition in human dwellings and cattle sheds.The main species in human dwellings were An.kochi,An.minimus,and An.sinensis,while the principal species in cattle sheds consist of An.kochi（223）,An.annularis（184）,An.vagus（131）,and An.jeyporiensis（129）.Furthermore,the composition in human dwellings of villages with and without cattle was significantly different.An.minimus（260） and An.kochi（49） were the most important species in villages with cattle,whereas An.kochi（481） and An.sinensis（124） were the key species in villages without cattle.A total of 1 075 mosquitoes were examined for sporozoites and 9 mosquitoes were found to be infected.Only three species,i.e.An.minimus（7/408）,An.aconitus（1/125） and An.pseudowillmori（1/101） were infected with malaria parasite.All sporozoites were identified as Plasmodium falciparum by sequencing,the target fragment was 204 bp.Conclusion The species composition of mosquitoes is complex in the study sites on the western part of China-Myanmar border,and An.minimus is the major malaria vector.Additionally,An.aconitus and An.pse-udowillmori are also confirmed as potential malaria vector in this area.