2005—2019年贵州省传疟媒介按蚊密度及种群监测

目的　了解2005—2019年贵州省传疟媒介按蚊密度、种群构成及生境分布，为制定全省输入性疟疾传播风险防控措施提供参考依据。方法　2005—2019年在贵州省分别采用人帐诱法和诱蚊灯法开展按蚊密度及按蚊种群监测，对捕获的按蚊进行形态学分类鉴定并计数，并对按蚊生境分布进行分析。 结果　2005—2019年贵州省传疟按蚊密度自6月上旬开始上升，在7月上旬达到高峰后开始下降，活动规律呈单峰型，最高密度为2018年8月上旬的57.34只/（人·夜）、最低密度为2009年10月下旬的1.29只/（人·夜）；年均按蚊密度由2005年的17.91只/（人·夜）逐年缓慢降至2012年的12.34只/（人·夜），下降了38.02%（χ2]趋势 = 115.04，P < 0.01），2017—2019年按蚊密度有上升趋势（χ2] 趋势 = 420.00，P < 0.01）。2017—2019年贵州省传疟按蚊在19：00至次日7：00监测时间内均能被捕获，总体密度呈先上升后下降趋势，19：00—21：00为全省传疟按蚊活动高频时段。2005—2019年贵州省采用诱蚊灯法共监测938次，累计捕获按蚊52 781只，其中中华按蚊49 705只、微小按蚊804只、嗜人按蚊238只、其他按蚊2 034只，各类按蚊构成差异有统计学意义（χ2] = 165.68，P < 0.01）。2017—2019年，在贵州省人房、户外和畜房三类生境中累计捕获传疟按蚊24 557只，以畜房捕获按蚊最多，占总捕获按蚊总数的67.65%；人房捕获按蚊最少，占12.01%；不同生境捕获按蚊数量差异有统计学意义（χ2] = 55.04，P < 0.01）。在捕获的按蚊种类中，三类生境均能捕获中华按蚊、嗜人按蚊和微小按蚊，其中以中华按蚊最多，占98.07%；嗜人按蚊最少，占0.09%。结论　贵州省原疟疾流行区传疟媒介种群结构发生了改变，中华按蚊取代了微小按蚊和嗜人按蚊成为全省主要传疟媒介；传疟按蚊密度近年来有上升趋势，捕获的按蚊种类及数量均有所增加，有引起输入性疟疾本地传播的潜在风险。今后需在贵州省长期、持续、全面开展传疟媒介监测。

Surveillance of malaria vector Anopheles in Guizhou Province from 2005 to 2019

Objective　To understand the density, populations and habitats of malaria vector Anopheles in Guizhou Province from 2005 to 2019, so as to provide the evidence for formulating the countermeasures to tackle the risk of local transmission of imported malaria in the province. Methods　The malaria vector Anopheles density and populations were monitored using human?bait trapping and light trapping techniques in Guizhou Province from 2005 to 2019, and all captured Anopheles was morphologically identified and counted. In addition, the distribution of Anopheles habitats was investigated. Results　During the period from 2005 through 2019, the malaria vector Anopheles density increased from early June in Guizhou Province, peaked on early July and then declined, which appeared a single peak. The greatest Anopheles density was seen on early August, 2018 57.34 mosquitoes/(person?night)], and the lowest density was found on late October, 2009 1.29 mosquitoes/(person?night)]. The annual mean Anopheles density slowly reduced from 17.91 mosquitoes/(person?night) in 2005 to 12.34 mosquitoes/(person?night) in 2012, with a 38.02% reduction (χ2] trend = 115.04, P < 0.01), while the annual mean Anopheles density showed a tendency towards a rise from 2017 to 2019 (χ2] trend = 420.00, P < 0.01). The malaria vector Anopheles was captured during the period between 19：00 and 7：00 of the next day in Guizhou Province from 2017 to 2019, with the overall density appearing a tendency towards a rise followed by a decline, and the Anopheles activity was highly frequent during the period between 19：00 and 21：00. The malaria vector Anopheles was monitored for 938 times using the light trapping method in Guizhou Province from 2005 to 2019, and a total of 52 781 Anopheles mosquitoes were captured, including 49 705 An. sinensis, 804 An. minimus, 238 An. anthropophagus, and 2 034 other Anopheles mosquitoes, with a significant difference seen in the Anopheles composition (χ2] =165.68, P < 0.01). From 2017 to 2019, a total of 24 557 Anopheles mosquitoes were captured in human housings, outdoors and livestock housings in Guizhou Province, with 67.68% captured in livestock housings and 12.01% in human housings, and there was a significant difference in the number of Anopheles mosquitoes captured from the three types of habitats (χ2] = 55.04, P < 0.01). An. sinensis, An. minimus and An. anthropophagus were captured form all three types of habitats, in which 98.07% was An. sinensis, and 0.09% was An. anthropophagus. Conclusions　The population structure of malaria vector Anopheles has changed in historically malaria?endemic areas of Guizhou Province, and An. sinensis has replaced An. minimus and An. anthropophagus to become the predominant malaria vector. The malaria vector Anopheles density has shown a tendency towards a rise in Guizhou Province during the recent years, and there have been a rise in the type and number of Anopheles mosquitoes, leading to a potential risk of local transmission of imported malaria. Long?term, persistent and extensive surveillance of malaria vectors is recommended in Guizhou Province.