Surveillance of malaria vectors in Anhui Province from 2016 to 2018

Abstract

To understand the population distribution, density, seasonal fluctuation and nocturnal activity of malaria vectors in Anhui Province from 2016 to 2018, so as to provide a data support for formulating the control strategy for imported malaria during the malaria post-elimination stage. The malaria vectors were monitored in 105 counties (cities or districts) of Anhui Province from 2016 to 2018, and the population density, seasonal fluctuation and nocturnal activity of the mosquitoes were observed using the lamp trapping and human bait trapping methods. The density of Anopheles mosquitoes was compared among different years, regions and mosquito-capturing sites. Anopheles mosquitoes were captured in 103 counties (cities or districts) of Anhui Province during the period from 2016 to 2018, and a total of 32 494 mosquitoes were captured using the lamp trapping method and 36 228 captured using the human bait trapping method. All captured mosquitoes were morphologically identified as Anopheles sinensis, and no An. anthropophagus was found. The density of An. sinensis peaked from June to August, and the peak nocturnal activity was found during the period between 19∶00 and 23∶00. Among all mosquito-capturing sites, the highest mosquito density was seen in the livestock and poultry sheds (H = 18.835, P < 0.05). The density of An. sinensis varied significantly in regions in 2016 and 2017 (H = 16.655 and 11.566, P < 0.01), and a low density was found in north of the Huai River. An. sinensis is widely distributed in Anhui Province, which is the currently predominant malaria vector in the province. During the malaria post-elimination stage, the malaria vector monitoring should be intensified and vector control interventions should be timely adopted in epidemic foci of Anhui Province to prevent the local re-transmission of overseas imported malaria.