Written Reply to Parliamentary Question on Dengue by Ms Grace Fu, Minister for Sustainability and the Environment

09 MAY 2022

Written Reply by Ms Grace Fu, Minister for Sustainability and the Environment, to Parliamentary Question on Dengue

Mr Ang Wei Neng: To ask the Minister for Sustainability and the Environment (a) what additional steps will be considered by the Ministry to reduce the number of dengue cases; and (b) whether an update can be provided on the use of Wolbachia-Aedes suppression technology in Singapore.

Mr Lim Biow Chuan: To ask the Minister for Sustainability and the Environment what other measures can be taken to deter mosquito breeding in homes and common areas such as drains.

Answer:

  1. Dengue cases in Singapore have been rising sharply since March 2022, with over 6,000 dengue cases reported by end-April. This is more than the 5,258 dengue cases in the whole of 2021. The National Environment Agency (NEA) has been working with partner agencies and Town Councils to intensify inspections, flushing of drains and chemical treatment in dengue cluster areas, to remove potential sources of mosquito breeding and suppress the adult mosquito population. About two-thirds of the 587 dengue clusters notified since the start of the year have been closed.

  2. Collective effort by the community is needed to bring down the number of dengue cases. NEA launched the annual National Dengue Prevention Campaign on 30 March 2022, ahead of the traditional peak dengue season from June to October, to rally members of the public and stakeholders to take immediate action to reduce mosquito breeding and protect themselves against dengue. New purple dengue alert banners have been deployed in areas with persistently high Aedes aegypti mosquito populations. This is to raise awareness of the greater risk of dengue transmission in these areas and encourage the public to take immediate action against mosquito breeding.

  3. NEA has been working with grassroots organisations and the People’s Association (PA), to intensify outreach efforts and distribute insect repellent through house visits and community events. We have deployed volunteers to areas with high footfall, such as hawker centres and transport hubs, and worked with partners such as supermarket operators to ramp up awareness of the dengue situation.

  4. Project Wolbachia is being implemented using in a phased approach to allow a rigorous evaluation of the effectiveness of the technology and an assessment of the deployment strategy. Thus far, Wolbachia-Aedes mosquitoes have been released at about 1,800 HDB blocks across study sites in Yishun, Tampines, Choa Chu Kang and Bukit Batok towns and within 5 square kilometres of landed estate at Marine Parade, comprising some 160,000 homes. NEA has observed up to 98 per cent suppression of the primary mosquito vector of dengue, Aedes aegypti, and up to 88 per cent fewer dengue cases in study sites with at least one year of Wolbachia-Aedes mosquito releases.

  5. Nonetheless, the Wolbachia technology is not a silver bullet and cannot replace the basic preventive actions that everyone must take to remove stagnant water and prevent mosquito breeding. With the traditional peak dengue season still ahead, NEA and partner agencies will press on with efforts to reduce the local mosquito population, including taking strong enforcement action against egregious cases of mosquito breeding. Town Councils face fines of up to $5,000 for mosquito breeding found in common breeding habitats such as roof tops and drains, during cluster operations. Poorly maintained construction sites that are found to harbour mosquito breeding may be issued with Stop Work Orders or face prosecution in court. Offenders in households found with repeat mosquito breeding offences and multiple mosquito breeding habitats may be sent to court, and upon conviction, face a fine of up to $5,000, or imprisonment for a term not exceeding three months, or both. Heftier penalties will be given for subsequent court convictions. Thus far this year, NEA has issued 38 Stop Work Orders to construction sites and 6 contractors were charged in court for repeat offences. During the same period, 960 enforcement actions were taken against occupiers of various premises for mosquito breeding.

  6. Residents living in dengue clusters should take extra precautions as the virus is circulating in their local community. Those who suspect that they have dengue fever should seek medical attention immediately. Residents who have been diagnosed with dengue should apply insect repellent regularly to prevent mosquito bites and stop the onward transmission of dengue by mosquitoes to their family members and the community.