P47 - Container-Specific Breeding Site Dynamics and Their Contribution to Aedes Abundance in Urban Dhaka, Bangladesh

Abstract: Dengue, caused by the DENV virus of the genus Flavivirus, is primarily transmitted by Aedes aegypti and Aedes albopictus, both highly adapted to human environments. These container-breeding mosquitoes utilize a wide range of natural and artificial water-holding sites, making control efforts challenging. Understanding larval density and container preference is not only essential for developing effective vector management strategies but also to understand their availability and occurrence in certain area.

Larval Survey were conducted weekly in 2700 sites in Dhaka, Bangladesh from June 2024 and September 2025. Random sampling was applied across a diverse range of wet container and the positive containers were systematically recorded. Container type was identified under 3 categories: structure of container, container material and size of the container. Breeding preference ratios (BPRs) were calculated using Index of Available Containers, the Index of Contribution to Breeding Sites, larval density and container occurrence index.

Out of 50 container type surveyed, 47 containers were found positive. Flooded floor (48.4%), basement/parking (17.1%), and plastic drums (13.7%) collectively accounted for nearly 80% of total larval productivity, whereas the remaining containers contributed less than 20%. Larva per container varied considerably, with flooded floors (~6,638 larvae), discarded food wrappers (~1,746 larvae), and pits (~1,667 larvae) exhibiting the highest larval rates, while small containers such as plastic bottles, buckets, and polythene bags yielded fewer than 1,000 larvae. Large containers, including water tank(cement) and flooded floor showed moderate larval occurrence (~40–70%), while they were responsible for the majority of overall larval output ( >60% of total larvae). In contrast, small containers such as coconut shells and bamboo stumps, although showed 100% occurrence, contributed minimally (< 1%) in larval density.

Aedes productivity is driven mainly by a few high-yield large containers, highlighting the need to target both these and persistently positive small habitats for effective vector control.