Abstract: Objective To investigate the population density of Anopheles vector of malaria after elimination of malaria in Hangzhou, China, and to provide a basis for risk assessment of imported malaria transmission and development of control strategy. Methods Ten districts, counties, or cities in Hangzhou were selected as malaria vector monitoring sites from 2018 to 2019. The density of adult (malaria vector) and larval mosquito populations were monitored by lamp-trapping, human-trapping, and dip survey methods. The data of confirmed cases of vivax malaria in Hangzhou from 2016 to 2020 were collected. The characteristics of malaria vector and epidemic were analyzed. Results A total of 1 686 mosquitoes were captured by lamp-trapping from 2018 to 2019. Of malaria vectors, only An. sinensis (116, 6.88%) was captured in the suburb and rural areas. A total of 834 An. sinensis adults were captured by human-trapping. The density was the highest in late July, which was 0.56 mosquitoe/person-hour in suburb areas and 5.63 mosquitoes/person-hour in rural areas (20.50 mosquitoes/person-hour in Chun'an county). Only 373 An. sinensis larvae were captured by dip survey in rice fields, with the density of 0.70, 0.05, and 0.02 larva/dip in Chun'an county, Tonglu county, and Lin'an district, respectively. The density of larvae was the highest in late July (0.54 larva/dip on average). From 2016 to 2020, 12 imported cases of vivax malaria were reported in Hangzhou, mainly in Yuhang district and Xihu district. The mean time from onset to diagnosis was (7.08±8.24) d. Conclusion An. sinensis is the only malaria vector consistently present in Hangzhou, which is mainly found in rural areas and varies significantly across seasons. Undetected imported cases of vivax malaria still pose a risk of transmission in Hangzhou.

Key words: Malaria, Malaria vector, Hangzhou

摘要： 目的 了解杭州市消除疟疾后传疟媒介按蚊种群及密度现状，为消除疟疾后输入性疟疾再传播风险评估及输入性疟疾防控策略的制定提供依据。方法 2018－2019年选取杭州市10个区（县、市）为传疟媒介监测点，采用诱蚊灯法、人诱法、勺捕法分别进行传疟媒介成蚊种群及成蚊、幼蚊密度监测，同时收集2016－2020年杭州市间日疟确诊病例个案调查资料，对传疟媒介及疟疾疫情流行特征进行分析。结果 2018－2019年各监测点采用诱蚊灯法共捕获各类蚊虫1 686只，传疟媒介按蚊中仅发现中华按蚊（116只，占6.88%），主要分布于郊区和农村，城区未捕获；人诱法成蚊密度监测共捕获中华按蚊834只，7月下旬密度最高，其中郊区点为0.56只/（人·h），农村点为5.63只/（人·h），淳安县达到20.50只/（人·h）；勺捕法幼蚊密度监测仅在稻田中捕获中华按蚊幼蚊373条，分布在淳安县、桐庐县和临安区，勺舀指数分别为0.70、0.05和0.02条/勺，7月下旬幼蚊密度最高（平均为0.54条/勺）。2016－2020年杭州市共确诊境外输入性间日疟病例12例，病例主要分布在余杭和西湖区；病例发病到确诊的时间平均为（7.08±8.24） d。结论 中华按蚊是杭州市持续存在、唯一的传疟媒介，主要分布在农村且有明显的季节性，境外输入性间日疟病例未及时发现仍存在再传播的风险。

关键词: 疟疾, 传疟媒介, 杭州