Project Wolbachia: Louis Ng says residents asking why release mosquitos that will bite them

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SINGAPORE — Member of Parliament Louis Ng on Wednesday (4 March) shared concerns from residents of his Nee Soon Group Representation Constituency (GRC) regarding a pilot project to curb the population of dengue-producing mosquito.

The MP asked Minister for the Environment and Water Resources (MEWR) Masagos Zulkifli during the ministry’s Committee of Supply debate for an update on Project Wolbachia, where male mosquitoes carrying the Wolbachia bacterium mate with females, causing them to lay eggs that do not hatch.

While the National Environment Agency (NEA) has been studying the programme since 2012, it first released the male mosquitos in trial areas in 2016.

The programme has since achieved 90 per cent suppression of the Aedes aegypti mosquito population within the Yishun and Tampines test sites. Masagos said that MEWR is considering expanding the project to more neighbourhoods in consultation with a dengue expert advisory panel.

Ng noted that the project has led to a 90 per cent drop in the mosquito populations in Nee Soon East. However, he asked how the ministry would be increasing awareness of the project, stating that residents had been asking him questions on it.

“Many asked me why we are releasing mosquitoes that will bite them. I tell them we're only releasing male mosquitoes and males don't bite,” he said.

“The next concern is that they tell me the males will attract the females who will then bite them. I tell them don't worry, it’s the males who look for the females.”

In response, Masagos said, “I hope to reassure residents that these male mosquitoes do not bite or transmit diseases, I say this in Parliament and ask residents to be patient and bear with the initial surge (of male mosquitos).”

Spike in dengue cases this year

Other MPs noted the spike of dengue cases this year as well as warmer weathers and rain, which would provide more breeding grounds for mosquitoes.

Dr Chia Shi-Lu noted that last week the NEA reported 110 dengue clusters, of which 25 are on red alert level, while Sylvia Lim stated that dengue cases at the beginning of this year have spiked against the same period last year, with several live clusters in Aljunied GRC.

Liang Eng Hwa also asked how the impact of climate change, such as warmer weather, would affect the management of dengue cases.

“Having been a dengue patient before myself last year I know how it is like to live through the illness,” he said. “We should spare no effort to minimise the cases of dengue in Singapore, not any less than how we manage COVID-19, and continue to seek new strategies to fight this virus.”

In response, Masagos said that Singapore has set up high-tech mosquito farms which optimise mosquito production, sort male mosquitoes from female, and transport male mosquitoes for release.

“We are scaling up the facilities production to 5 million male mosquitoes a week, over the next few years, to battle dengue,” he said. “This is a new and important means to future-proof ourselves against the faster breeding of mosquitoes as a result of higher temperatures brought by climate change.”

Project Wolbachia expansion on the cards?

During clarification, Lim asked why Project Wolbachia, having gone through a few phases, had not been deployed in dengue clusters. She also asked if the project will be deployed in these clusters.

In reply, Masagos said that despite the effectiveness of the project, the complaints and the disamenities that residents suffer from a sudden surge of mosquitoes have not abated.

“We are extremely careful in deploying this technology. Because while we are introducing something that is natural – Wolbachia is naturally occurring in mosquitoes – we are doing it artificially, and injecting huge numbers into the community,” he explained.

“So apart from the effectiveness of the technology, we also are mindful...of the disamenities that residents may suffer from suddenly having millions and millions of mosquitoes in the neighbourhood.”

The minister said that residents still complained to him about the large amount of mosquitoes despite knowing that they were Wolbachia mosquitoes.

“I think we need time to make sure that as we expand the areas where we deploy Wolbachia here, that the people are also used to this.”

Nevertheless, he added that he hopes to introduce fewer male mosquitoes over time, as the dengue mosquito population was suppressed.

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