We thank Mr Victor Lim for his feedback (Setback in war on dengue, June 12).

The National Environment Agency (NEA) is currently releasing male Wolbachia-Aedes mosquitoes covering about 5 per cent of HDB blocks in Singapore, namely in areas within Tampines, Yishun and, since May, in Choa Chu Kang and Bukit Batok towns.

The releases in Tampines and Yishun have resulted in a 90 per cent suppression of the urban Aedes aegypti mosquito population and correspondingly 65 to 80 per cent fewer dengue cases in these neighbourhoods.

These localised effects, however, are not expected to make a significant impact on the current dengue outbreak.

Because of the low Aedes aegypti populations and the absence of large clusters in both the release sites within Tampines or Yishun, no fogging has been carried out in these neighbourhoods.

The fogging of mosquitoes performed elsewhere does not affect the performance of Project Wolbachia in these sites.

Premise operators and managers should use thermal fogging judiciously and only when the mosquito population is high or when there is a dengue cluster.

Overuse and indiscriminate use can lead to insecticide resistance.

We are thankful for the support from residents and local stakeholders in the Wolbachia-Aedes release sites.

While we continue to ramp up the capacity of Project Wolbachia, we urge all to continue to keep the mosquito population low in your neighbourhood.

Project Wolbachia - Singapore is not the silver bullet to prevent the spread of dengue. It is still in the research trial phase, and is intended to complement, not replace, conventional vector control measures.

The community's support to suppress mosquito breeding within their homes continues to be key.

It is essential that everyone continues to remove stagnant water to deprive mosquitoes of their breeding habitats, regardless of whether there are releases of Wolbachia-Aedes mosquitoes in his neighbourhood.

Use of repellent to reduce mosquito bites and spraying of insecticide where necessary to control the adult mosquito population will also reduce the risk of being infected by dengue.

Ng Lee Ching (Associate Professor)

Director, Environmental Health Institute

National Environment Agency