Integrated vector management with the sterile insect technique component for the suppression of Aedes aegypti in an urban setting in Indonesia.

Background: Implementing the sterile insect technique (SIT) in areas with high-density target mosquito populations throughout the year is challenging. This study evaluated the effectiveness of releasing radiation-sterilized male Aedes aegypti mosquitoes, which were subjected to pre-release control measures in a highly urbanized city.

Methodology/principal Findings: A mark-release-recapture (MRR) trial was conducted to assess the performance of sterile male mosquitoes. The MRR results revealed that the life expectancy of irradiated mosquitoes was 1.2-8.8 days, and that their mean dispersal distance was 60.0-64.3 m. The estimated wild male population ranged from 1,475-2,297 male mosquitoes/ha. In the SIT trial, sterile male A. aegypti mosquitoes were released at a rate of 9,000 male mosquitoes/week/ha for 24 weeks. Pre-release control measures, including chemical fogging (Fludora Co-Max EW) and breeding site removal, were employed at the release site. A buffer zone was established by applying residual insecticide (K-Othrine PolyZone SC) and releasing sterile male mosquitoes. In the SIT trial, relative to control sites, the site with sterile male mosquitoes had considerably greater sterility in the field population (greater by 86%), resulting in reductions in the ovitrap density index, and number of wild female mosquitoes captured. In contrast, no significant reduction in ovitrap index was observed. However, despite the gradual recording of low values for egg hatching, ovitrap density index, and female capture, mosquito suppression was incomplete. The mosquito population rebounded shortly after the release of sterile male mosquitoes ended.

Conclusions/significance: This study underscores the critical role of integrated vector management when the SIT is implemented in highly urbanized areas. It also emphasizes the importance of combining vector control interventions to ensure they are tailored to the geographic context based on logistical feasibility, available local facilities, and local knowledge of the vector.