Committee of Supply debate: Ministry of the Environment and Water Resources

Field study to assess using special mozzies against dengue

It entails releasing bacteria-carrying male mosquitoes into environment; steps taken to safeguard public health

A field study will be conducted at the end of this year to assess if a special type of mosquito can be a weapon against dengue.

The male Wolbachia-carrying Aedes aegypti mosquitoes will be released into the environment in the small-scale study to be conducted by the National Environment Agency (NEA).

Speaking during the debate on the ministry's budget, Environment and Water Resources Minister Masagos Zulkifli said the Government was not embarking on the study "lightly", and had "studied this for years and taken all steps to ensure that public health and safety will not be compromised".

Only male mosquitoes, which do not bite, will be released.

Wolbachia is a naturally occurring bacteria that can be found in over 60 per cent of insect species, but not in dengue-carrying Aedes aegypti mosquitoes.

  • $1.9 billion 

    Total bill, up 13.1 per cent from last year.

    6,300 

    Number of dengue cases in the first three months of this year.

    43,000 

    Rat burrows found last year.

    800,000 

    Tonnes of food waste generated by Singapore last year - equivalent to two bowls of food per person every day.

When male mosquitoes carrying the bacteria mate with wild female mosquitoes, they produce eggs that do not hatch. This could help to suppress the number of Aedes aegypti mosquitoes in the long run. The method has been used in the fight against dengue in countries such as Australia and Brazil.

The study will look at the behaviour of these special mosquitoes in the built-up environment, such as how long they can live in the wild and their flight range. The data collected will help in the design of a future trial. Previously, studies were conducted in the laboratory by the Environmental Health Institute under the NEA.

Based on the NEA's assessment so far, the technology poses no or insignificant risk of negative impact on public health or ecology.

The NEA has appointed a research firm to identify any potential secondary environmental and social impact that may arise.

Dengue expert Tikki Pang said each country's situation is unique and "only time will tell" if the technology will work in Singapore.

"Any tool that helps in the battle against dengue should be considered and tested," added the visiting professor at the Lee Kuan Yew School of Public Policy at the National University of Singapore.

The announcement comes on the back of a sharp rise in the number of dengue cases this year. A total of 6,338 dengue cases were reported between January and March this year, almost three times as many as the 2,251 cases reported in the same period last year.

The authorities have warned that unless immediate action is taken to suppress the Aedes mosquito population, the number of dengue cases this year may exceed 30,000 - higher than the record set in 2013 when 22,170 cases were reported.

Several MPs also asked about the Government's plan to approve the dengue vaccine for use here.

Mr Masagos replied that it has been closely tracking the development of the vaccine. But as the vaccine is new, "we do not know yet whether its quality is what (the manufacturer) promised it to be".

A version of this article appeared in the print edition of The Straits Times on April 13, 2016, with the headline 'Field study to assess using special mozzies against dengue Committee of Supply debate: Ministry of the Environment and Water Resources'. Print Edition | Subscribe