Project Wolbachia to cover more than 50% of households in Singapore by October

SINGAPORE – By October, more than 800,000 households here will be covered by Project Wolbachia – an effort to prevent the spread of dengue by controlling the mosquito population – as it expands to five more areas in the Republic.

This means the initiative by the National Environment Agency (NEA) will exceed its target of providing coverage to 50 per cent of all households by the end of 2026, a goal set in 2024 by Minister for Sustainability and the Environment Grace Fu.

Between April and October, the programme will be progressively rolled out to Bukit Panjang, Little India, Pioneer, Toa Payoh and Ang Mo Kio, NEA said in a statement.

They will join areas such as Bukit Batok, Tampines and Serangoon, which are already under the project.

The project will start in April in Bukit Panjang, Little India and Pioneer, followed by Toa Payoh in June and Ang Mo Kio in October.

The release of male mosquitoes carrying the Wolbachia bacteria will be conducted twice a week in the morning at each site, with residents informed in advance via informational banners and posters displayed at residential lift lobbies or through letters.

The release schedule will be available on the NEA website. In response to queries, NEA said it will provide updates on additional expansions at a later stage.

The project involves infecting male mosquitoes with the Wolbachia bacteria in a laboratory. Female mosquitoes that mate with these male mosquitoes produce eggs that do not hatch.

The release of these male mosquitoes in high-risk dengue areas can thus help reduce the mosquito population over time.

“Reaching 50 per cent household coverage, including most areas at risk of large dengue outbreaks, will mark an important milestone for Singapore’s dengue control efforts,” said the agency.

It noted that while residents may see a temporary increase in the number of mosquitoes due to the release of the male Wolbachia-infected Aedes mosquitoes – which do not bite – studies have shown significant benefits in areas where they are released.

NEA cited a study by researchers from various institutions, published in the prestigious New England Journal of Medicine in February, which found that Aedes aegypti mosquito populations were reduced by 80 per cent to 90 per cent in areas covered by Project Wolbachia.

The dengue risk for residents in these areas fell by more than 70 per cent, while those living in adjacent areas were 45 per cent less likely to contract dengue compared with those in areas without releases.

“These results highlight the effectiveness of Project Wolbachia as a complementary tool in Singapore’s comprehensive dengue control strategy,” said the NEA, pointing to other moves such as the removal of stagnant water sources and community education initiatives.

Noting that Project Wolbachia marks its 10th anniversary in October, NEA described the project’s decade-long history as one of “innovative research with strong support from partners, stakeholders and the community”.

“The milestone underscores Singapore’s commitment to develop cutting-edge and effective approaches to combat dengue and other mosquito-borne diseases,” it added.

Senior Minister of State for Sustainability and the Environment Janil Puthucheary announced the expansion on his social media accounts.

He said that to prevent mosquitoes from breeding, residents should continue to remove stagnant water, taking steps such as overturning pails and changing the water in vases weekly. 

“Project Wolbachia works best when we all do our part,” he added.  

This comes amid a decrease in the number of dengue cases over the past year. There were 4,036 reported cases in 2025 – a 70 per cent drop from the 13,651 recorded in 2024.

There have been 344 cases in 2026 as at March 12 – less than half of the 950 cases seen over the same period in 2025.

In May 2025, NEA attributed the lower number of dengue cases in part to efforts such as Project Wolbachia, though experts have said the initiative’s impact on dengue numbers here will become more obvious only in the coming years.

Marsiling resident Shahrizal Ismail said he had noticed an increase in the number of mosquitoes in December, when the initiative was expanded to his neighbourhood, but added that he was not bothered by it. 

On the decrease in dengue cases here in 2025, the 43-year-old art team manager said: “If it’s really working, that’s great news.”

Sembawang West MP Poh Li San noted that her constituency – then part of Sembawang GRC – was a dengue cluster with hundreds of infections in mid-2022.

The introduction of Project Wolbachia to the area later that year helped improve the situation, she said.

“The number of cases of dengue dropped tremendously, and it has remained that way for the past three years,” said Ms Poh.

She added that while residents were initially annoyed by the large numbers of mosquitoes around their homes, particularly on release days, community engagement helped them understand the initiative’s importance and effectiveness.

Ms Poh, who chairs the Government Parliamentary Committee for Sustainability and the Environment, emphasised, however, that people should still do their due diligence in preventing mosquitoes from breeding.

“We must not think that Project Wolbachia is a silver bullet,” she said.