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The release of Wolbachia-infected mosquitoes has led to a 50% to 80% reduction in dengue cases in Selangor
According to the New Straits Times, Health Minister Datuk Seri Dr Dzulkefly Ahmad told the Dewan Rakyat that public health studies conducted on the release of these special mosquitoes showed encouraging results.
"During the early phase of implementation, the results of public health studies in six dengue outbreak localities in Selangor showed a reduction in dengue cases between 50% to 80% compared with control localities," he said in a written parliamentary reply on Tuesday, 27 January.
Dr Dzulkefly was responding to Mohd Hasnizan Harun (PN–Hulu Selangor), who asked whether the Ministry of Health had conducted comprehensive environmental and public health impact studies following the release of Wolbachia-infected mosquitoes, and whether continuous monitoring was in place to ensure safety.
Federal Territories of Kuala Lumpur and Putrajaya Health Department officers release Wolbachia-infected mosquitoes in Precinct 18, Putrajaya in December 2025.
Image via Perbadanan Putrajaya (Facebook)Wolbachia is a naturally occurring bacterium found in insects and was introduced into Aedes mosquitoes in Malaysia to help reduce dengue transmission
This works because when Wolbachia-carrying male mosquitoes mate with females, their eggs will fail to hatch, gradually reducing the local mosquito population.
The approach is considered safe and sustainable, as Wolbachia cannot infect humans or survive outside insect cells. It is also not classified as a genetically modified organism (GMO), since the bacteria occurs naturally in insects.
Wolbachia-infected mosquitoes.
Image via Perbadanan Putrajaya (Facebook)Dr Dzulkefly said early assessments have examined how Wolbachia-infected Aedes mosquitoes interact with existing mosquito populations in the environment
As of December 2025, he said Wolbachia-infected mosquito release operations have been carried out in 51 localities across eight states and territories, including Selangor, Kuala Lumpur, Putrajaya, Johor, Penang, Melaka, Kelantan, Pahang, and Negeri Sembilan.
He said evaluations conducted after six years of implementation found that 28 of the 51 localities met the assessment criteria and were deemed successful.
