Four years after laboratory studies on using male Wolbachia-carrying Aedes aegypti mosquitoes to control the mosquito population were conducted, about 3,000 of the insects were set free in Braddell Heights on Tuesday (Oct 18), one of the three sites selected for a small-scale field study.
Regular releases of these mosquitoes carrying Wolbachia, a naturally-occurring bacteria, will be conducted over the next six months, to better understand how they fare in Singapore’s urban environment.
The first release of these mosquitoes at the other two selected sites — Tampines West and Nee Soon East — will be on Oct 28 and Nov 15, respectively, the National Environment Agency (NEA) said on Tuesday.
One to three mosquitoes per person will be released regularly at public spaces – such as stairwells and void decks – around each of the three housing estates as part of the trial.
The study will allow the NEA to move towards using these infected male mosquitoes to suppress the population of the dengue-transmitting mosquitoes in the community. As male mosquitoes do not bite, those released in the study will not transmit any diseases.
“The results (of the study) will help to calibrate the strategy for maximal mosquito suppression and reduction of dengue in Singapore,” said Dengue Expert Advisory Panel member, Associate Professor Vernon Lee of the National University of Singapore’s Saw Swee Hock School of Public Health.
A comprehensive risk assessment of Wolbachia technology has determined it to be safe, with no risk to human health and insignificant risk to ecology, the NEA said.
Mr Seah Kian Peng, a Member of Parliament for Marine Parade GRC, and some residents of Bradell Heights on Tuesday joined NEA officers in releasing the Wolbachia-carrying mosquitoes.
“…We are happy to support NEA’s efforts in exploring new tools and technologies to improve dengue control in Singapore,” Mr Seah said in a Facebook post.
Braddell Heights resident Tan Jiah Yong, 83, is among those who agreed to have fan-based mosquito traps and Gravitraps, black cylinder-shaped containers, in her home. “It’s for the good of residents and it’s just placing a fan outside the house,” said Mdm Tan.
Participating residents are asked to change the mesh daily and to place them in Ziploc bags without flattening them. The Ziploc bags then go into a plastic container that is hung outside their unit.
Student Rachel Koh, 20, said she hoped the field study would work in reducing the mosquito population. There are “a lot of mosquitoes in this area” and she is bitten “easily twice a day”, she added.
For now, the sight of significantly more mosquitoes buzzing around will take some getting used to for a few residents.
Mr Patrick Foo, 55, noticed many more of them in the house on Tuesday and guessed it could be due to the release of the Wolbachia-carrying mosquitoes.
“Even if they don’t bite, it’s so irritating,” he said, pointing to a cluster buzzing around a vase of artificial flowers.
His family is hosting a fan-based trap because his brother, who was once hospitalised with dengue, decided to take part, said Mr Foo.
Source: TODAY Online
