Wolbachia-Aedes Mosquito Suppression Strategy

Field Study to Test Targeted Release Strategy

Field study to test targeted release strategy

Targeted release strategy in HDB estates

Since May 2020, NEA expanded releases of male Wolbachia-carrying Aedes aegypti (Wolbachia-Aedes) mosquitoes to selected dengue high-risk neighbourhoods in Choa Chu Kang, Keat Hong, Hong Kah North, and Bukit Gombak. These neighbourhoods were selected due to their consistently high Aedes aegypti mosquito populations.

This targeted approach, which zeroes in on high-risk areas, differs from the “rolling” approach adopted in Yishun and Tampines, where release sites were gradually expanded to adjacent neighbourhoods.  

Release schedule

Preliminary findings

Ongoing releases in parts of Choa Chu Kang, Keat Hong and Hong Kah North constituencies have reduced the urban Aedes aegypti populations, with most areas having fewer than 10 mosquitoes caught per 100 traps per week. The heat map below shows the “eraser effect”, where previously dark red areas (indicating high Aedes aegypti mosquito population) gradually faded to low mosquito population from May/June 2020 to March 2022. 

With the promising results, NEA expanded and carried out releases at other high-risk areas in Choa Chu Kang and Bukit Batok towns in Oct 2021 and May 2022. The targeted strategy in these areas remain unchanged, which means releases will be conducted on pockets of areas with perennially high Aedes aegypti mosquito populations and persistent dengue transmission. 

Heat map showing mosquito population suppression in CCK

 

Targeted release strategy in landed estate

Following the good results of Project Wolbachia in high-rise residential HDB estates, NEA has expanded releases to the Marine Parade landed estate area. This study will help NEA develop strategy and tactics for the use of Wolbachia technology in high-risk landed estates.

Vans equipped with release automation technology are deployed to conduct releases. The use of van releases is part of NEA’s efforts to incorporate automation into releases so that we can cover larger areas more effectively as Project Wolbachia scales up.

Since April 2021, NEA has conducted mosquito trap studies and small-scale trial releases to collect data in preparation for the large-area releases. Residents were engaged and volunteers hosted different mosquito traps in their homes for mosquito surveillance.

Release schedule

Targeted release strategy in construction sites

As part of the expansion, releases will also be carried out at construction sites within the study sites. NEA is working with relevant stakeholders, including construction companies, to guide them on the surveillance and release of male Wolbachia-Aedes mosquitoes at such premises. This is part of our strategy to achieve better suppression at the study sites, by covering different terrains and landscapes.