177 - New twist in dengue fight: Aedes aegypti's nocturnal feeding habits challenge current control measures

Abstract: Dengue, one of the world's quickly-spreading diseases, is the principal vector transmits the disease daytime-biting mosquito Aedes aegypti (Linnaeus). Our study, conducted between 2021 and 2024 in Dhaka, Bangladesh, determined significant night-time biting behavior of Ae. aegypti. The goal was to improve our understanding of their behavior and to develop effective vector management strategies. Using the human bait technique, female mosquitoes were captured in seven surveys across five areas of Dhaka. Mosquitoes were captured with mouth aspirators and identified by species. Data on mosquito abundance, species distribution, biting patterns, and landing rate per man hour (PMH) were analyzed. A total of 210,042 mosquitoes were captured, including Ae. aegypti, Ae. albopictus (Skuse), Armigeres subalbatus (Coquillet), Culex fuscocephala Theobald, Cx. quinquefasciatus Say, Cx. Tritaeniorhynchus Giles, Mansonia annulifera (Theobald), and Mn. uniformis (Theobald). The highest adult mosquito abundance was recorded in the dry winter months, while Ae. aegypti abundance peaked during the monsoon. Most mosquito bites occurred between 6-8 PM, with peak density at 7-8 PM, Ae. aegypti were utmost active at 5-6 PM (PMH density: 0.96). Remarkably, Ae. aegypti were also biting during night hours, particularly between 8-10 PM, with PMH densities of 0.16 and 0.10 at 8-9 PM and 9-10 PM, respectively. This nocturnal biting behavior has significant implications for dengue control strategies, especially those focused-on human-feeding vectors. Research also shows the adaptation of Ae. aegypti to artificial lighting represents a new challenge, highlighting the necessity to revise existing control strategies. The findings of our study provide essential information on the night-time biting patterns of Ae. aegypti, crucial for developing more effective dengue prevention approaches.