广西微小按蚊种群密度地理分布及种类分子鉴定研究

Study on the geographical distribution of population density of Anopheles minimus and molecular identification of the species in Guangxi

目的研究20世纪以来广西壮族自治区(广西)微小按蚊的种群密度和地理分布,为疟疾防治提供参考。方法收集广西20世纪50-90年代微小按蚊资料及疟疾发病率,于2004-2010年在不同经纬度原以微小按蚊为主要传播媒介的疟疾流行区收集该蚊成蚊,采用形态学和PCR方法鉴定采集的微小按蚊样品。结果1957-1998年对全自治区不同经纬度媒介按蚊调查,92个县中有56个县存在微小按蚊;2004-2007年在该蚊活动频繁的36个县的乡村收集按蚊,仅在20个县40个媒介点采集到微小按蚊244只;采用种类分子鉴定,除百色市旺甸村有微小按蚊种类A存在外,其他地区均为微小按蚊种类C。2008年后全自治区各县疟疾疫情发病率已降至0.1/万。结论目前在广西存在微小按蚊种类A和C两种,以种类C为主;全自治区不同经纬度的微小按蚊种群密度和分布范围已经明显减少,该蚊有可能不再是该区域疟疾传播的主要媒介。

Objective To study the geographical distribution of population density of Anopheles minimus and molecular identification of the species since the 20th century in Guangxi Zhuang Autonomous Region for providing scientific data for its prevention and control.Methods Data on An.minimus and malaria incidence from 1950s to 1990s in Guangxi were collected,with the adult An.minimus collected in 2004 to 2010 in the Autonomous Region in the malaria endemic areas at different longitude and latitude where An.minimus was previously the major vector and the collected samples identified by morphology and PCR assay.Results It was found that of all of the 92 counties of the Region,there were 56 counties at different longitude and latitude locations in which An.minimus existed from 1957 to 1998.An.minimus were collected in the villages of 36 counties from 2004 and 2007 where the insects were prevalent.Only 244 An.minimus were collected at the 40 surveillance sites of 20 counties,and PCR molecular identification of the species revealed that An.minimus from Wangdian village,Baise district was of An.minimus A.The insects collected from other sites were all of An.minimus C.The incidence of malaria in all the counties of the Region was reduced to 0.1/10 000 after 2008.Conclusion Currently there exist two species of An.minimus in Guangxi,with An.minimus C being the predominant species and An.minimus A about to die away.There is a substantial decrease in the population density and geographical distribution range of An.minimus in Guangxi.It is likely that An.minimus will no longer be the major vector for malaria in the region.