中国-缅甸边境地区微小按蚊种群密度及其生态习性调查

Investigation on population density and bionomics of Anopheles minimus in China-Myanmar border

目的了解我国云南省中国-缅甸(中缅)边境地区微小按蚊种群密度及其生态习性,为该地区疟疾输入继发传播风险评估及制定有针对性的媒介控制措施提供科学数据。方法选择云南省中缅边境地区腾冲市的5个乡作为调查点,每个乡选取2个自然村,于2015年5-12月开展现场调查。采用诱蚊灯诱捕法、双帐人诱法通宵监测微小按蚊种群密度及其叮人习性,通过定人、定时、定点的人工捕获法,对成蚊的生态习性、蚊幼虫密度及其孳生地进行调查;利用多重PCR方法鉴定成蚊的胃血来源。结果共捕获按蚊4 089只,经形态学鉴定分别为中华按蚊、微小按蚊、带足按蚊、库态按蚊、美彩按蚊、银足按蚊和多斑按蚊,以中华按蚊(2 055/4 089,50.26%)、带足按蚊(1315/4 089,32.16%)和微小按蚊(563/4 089,13.77%)为优势种。微小按蚊密度高峰在9月,其中牛房和人房蚊密度分别为32.70和12.20只/(灯·夜),叮人率为2.0只/(人·夜)。微小按蚊在日落后通宵均有吸血活动,吸血场所以牛房为主,人房与牛房捕获吸血的微小按蚊比例为1∶10。微小按蚊偏吸牲畜血,人血指数为0.23。在孳生地共捕获蚊幼虫423条,以池塘捕获数量最多,为266条。结论腾冲市经过长期的疟疾防治工作,微小按蚊种群数量得到了有效控制,但蚊种的部分生态习性可能发生改变,还需继续加强监测。

Objective To study the current density and ecological characteristics of Anopheles minimus in China-Myanmar border areas and provide the evidence of risk on malaria reintroduction across the borders. Methods The study sites were selected from five townships in Tengchong county of Yunnan province located in China-Myanmar border. In each township, two villages were selected for mosquito sampling. The light trapping and human bait trapping were conducted for investigation on population density and human bite behavior from May to December in 2015. The investigation on ecological characters of both adults and larvae was carried out by experienced staff in the field with regular time intervals. The multiple polymerase chain reaction （PCR） was used to detect the blood meal source in mosquitoes. Results Totally 4 089 Anopheles mosquitos were trapped. There were seven species identified by morphological characters：An. sinensis, An. minimus, An. peditaeniatus, An. culicifacies, An. splendidus, An. argyropus, and An. maculatus. The predominant species identified based on population density were An. sinensis （2 055/4 089, 50.26%）, An. peditaeniatus （1 315/4 089, 32.16%）, and An. minimus （563/4 089, 13.77%）. The peak of population density of An. minimus was observed in September. There were 32.70 and 12.20 mosquitoes/night in cattle shelter and human dwelling respectively. The human bite rate was 2.0 bites/（human·night）. Anopheles minimus was observed to exhibit blood sucking behavior all night after sunset. The preferred blood seeking place was found in cattle shelter, the ratio compared with human dwelling was 10：1. The human blood index was tested as 0.23. A total of 423 An. minimus larvae were collected, 266 from the pond around village. Conclusion Anopheles minimus populations were well controlled after several years á efforts. It had limited impact on malaria transmission locally. But the ecological characteristics were found to be different from previous studies, further surveillance is required even after malaria elimination certification.