In 2016, the National Environmental Agency (NEA) revealed plans to release Wolbachia-infected male mosquitos to drive down mosquito numbers.

Reduce Aedes mosquitoes breeding

Named Project Wolbachia, it involves phased field studies to evaluate the use of such male Wolbachia-Aedes mosquitos to gradually reduce the Aedes mosquito population and curb the spread of the dengue, chikungunya and Zika virus.

These male mosquitos have been infected with the Wolbachia bacteria, which renders them sterile.

This means that when they mate with female Aedes mosquitoes, the eggs will not hatch, or their offspring will inherit the disease and be rendered infertile.

Positive results

The first phase of the study was conducted in October 2016 and has achieved more than 50 per cent suppression in Tampines, Yishun and Serangoon where the mosquitoes were released. There have been gradual improvements achieved in the research.

According to a press release by NEA on Oct. 7, 2019, phase 3 of the study yielded favourable results.

Phase 3 evaluated if the mosquito suppression that has already been achieved can be expanded to cover larger areas sustainably.

The release area covered 60 blocks in Tampines and 84 blocks in Yishun, nearly four times the size of the first project area.

Phase 3 of the study also made use of automated efforts to sterilise and release the male mosquitoes.

The population of urban Aedes aegypti mosquitoes at the Nee Soon East and Tampines West study sites has since been suppressed by at least 90 per cent.

In November 2019, NEA will extend the release of male Wolbachia-Aedes mosquitoes to more neighbourhoods at Nee Soon East and Tampines West as part of the fourth phase of the project.

In Phase 4, NEA will scale up the production and release of the Wolbachia-Aedes male mosquitos, with a new mosquito production facility and technology.

Wolbachia-infected mosquitos not a "silver bullet"

Minister Masagos Zulkifli said in September that the project is still under research and development, and should not be seen as a "silver bullet" to the Aedes mosquito problem.

Residents in areas being tested should still continue to carry out mosquito control procedures, such as the 5-Step Mozzie Wipeout as persistent breeding of mosquitoes will still undermine the effectiveness of Project Wolbachia.

Along with the residents' response, community outreach efforts and existing eradication measures remain as key strategies used by the Ministry of Environment and Water Resources (MEWR) in combating the dengue virus.

Top image via NEA's Facebook video