Sharing of information on areas with relatively higher Aedes aegypti adult mosquito population will help key stakeholders, community partners and residents to take proactive preventive measures
Singapore, 23 August 2019 – The National Environment Agency (NEA) is working with key stakeholders to strengthen collective efforts in the fight against dengue, with a new initiative to share information on areas with relatively higher Aedes aegypti adult mosquito population, gathered from NEA’s Gravitrap surveillance system. This additional information will be made available on the NEA website [www.nea.gov.sg/dengue-zika/Aedes] from today, 23 August 2019, and will be updated monthly. With the Aedes aegypti mosquito as the primary vector for the transmission of dengue, and its high population being one of the reasons for the high dengue cases experienced this year, information on areas with relatively higher mosquito population will serve as a useful indicator for early intervention, to facilitate targeted action by key stakeholders, community partners and residents.
Update on dengue situation
2 Over the past six months, NEA has been working intensively with key stakeholders from various Government agencies in the Inter-Agency Dengue Task Force (IADTF), Town Councils (TCs), construction site management, community partners and residents, to strengthen our collective efforts in the fight against dengue. Through these efforts, we have closed 854 of the 1,013 dengue clusters notified since the start of 2019 (as of 22 August 2019). The number of weekly dengue cases has declined from a high of 664 in the second week of July, to 525 in the second week of August. Some of the largest dengue clusters, in Woodlands, Upper Thomson, Chai Chee and Pasir Ris, have also closed, with some still under close surveillance. However, despite the progress made, the number of weekly dengue cases remains persistently high at above 500. Even as clusters are progressively closed, we still have some rather persistent clusters, such as at Aljunied Road and Changi Road, as well as newer clusters being formed, in Choa Chu Kang Avenue 2 and 4 and Jalan Eunos. Common to all the past and present clusters, the Aedes mosquito population and number of mosquito breeding detected in homes at the dengue cluster areas, have been found to be higher than the national average or that at non-dengue cluster areas.
New indicator on Aedes aegypti adult mosquito population and higher dengue risk areas
3 Since 2017, NEA has been using Gravitrap data to monitor the Aedes adult mosquito population and guide its preventive inspection of homes at HDB residential estates. About 50,000 Gravitraps have been deployed islandwide at HDB estates since 2017, with another 14,000 to be rolled out and deployed at landed estates and newly completed HDB estates from the second half of 2019. Through the Gravitrap surveillance system, NEA was able to detect and remove 21 per cent more mosquito breeding habitats in 2018, compared to in 2017. Gravitraps have also been effective in helping NEA remove a large number of Aedes aegypti adult mosquitoes, including infected female mosquitoes. Resource optimisation from such a data-driven surveillance system has also allowed NEA to re-deploy manpower for other urgent dengue prevention tasks.
4 The high Aedes aegypti mosquito population is one of the key reasons for the high dengue cases experienced this year. Areas with relatively higher Aedes aegypti adult mosquito population have a higher risk of dengue transmission, especially during the peak dengue season. Thus, starting from 23 August 2019, information on areas with relatively higher Aedes aegypti adult mosquito population will be made available on the NEA website, to provide an additional source of information to heighten the awareness of the community to the risk of dengue, and to guide them in taking more proactive mosquito prevention measures. The data will be updated monthly. This proactive effort supplements the existing comprehensive national dengue prevention and control efforts, which bring together our key stakeholders such as community partners, residents, Government and corporate entities, to focus on collective mosquito prevention measures.
5 Mr. Chew Ming Fai, NEA’s Director-General Public Health, said: “With the high number of dengue cases this year, we need to take a holistic whole-of-community approach to fighting dengue, focusing on both dengue cluster areas as well as non-dengue cluster areas, which may be at risk of becoming dengue cluster areas in the future. We hope that the sharing of information on areas with relatively higher mosquito population will serve as a useful lead indicator for our stakeholders to take pre-emptive measures in reducing potential mosquito breeding habitats, thus lowering the risk of dengue transmission and future clusters from being formed.”
Benefits to Town Councils and homeowners/ occupants
6 For Town Councils (TCs), this additional Gravitrap surveillance data can help them prioritise their dengue prevention and control measures, and target areas with higher mosquito population. These measures can include stepping up the cleaning of drains in certain areas, and removing discarded receptacles to prevent chokes and stagnant water at all times. Areas that TCs can check to look out for mosquito breeding include: inspection chambers, lightning conductor pits, pump rooms, water tanks, as well as rooftops and gullies. Granular insecticide or Bti can be added to stagnant water bodies that cannot be removed.
7 Similarly, residents living in areas with relatively higher Aedes aegypti adult mosquito population are urged to help reduce the mosquito population, by regularly practising the 5-step Mozzie Wipeout, and reminding their families, friends and neighbours to remove stagnant water from within and around their homes.
Lowered population immunity, warmer temperature and climate change
8 Besides the increase in the Aedes mosquito population, lowered population immunity and warmer weather are the other two factors contributing to the high number of dengue cases this year. Climate change is anticipated to worsen the spread of dengue, as higher temperatures facilitate faster development of the Aedes aegypti mosquito vector and faster replication of the dengue virus. Annual average temperatures in Singapore are anticipated to continue rising, with rainstorms becoming more frequent and intense. These conditions are conducive for the continual introduction of new and reemerging vector-borne diseases, and more frequent pandemics of such diseases.
Concerted and proactive preventive efforts by key stakeholders, community partners and residents
9 NEA has not been alone in the fight against dengue. Fighting dengue requires the concerted effort of the whole community, including residents, contractors, and business owners, who all have a part to play in preventing and stopping dengue transmission. Continued vigilance and action is needed by all to eliminate potential mosquito breeding habitats.
10 During a dengue peak period, taking a pre-emptive approach in heightening dengue awareness and mobilisation of the community for dengue prevention efforts, are key. These involve the expansion of dengue prevention efforts from dengue cluster areas, to also include other relatively higher risk, non-dengue cluster areas, which have relatively higher Aedes aegypti mosquito population.
11 We encourage everyone to be an advocate of dengue prevention, and to remind his or her family members and neighbours to join in the collective effort to stop the dengue transmission cycle, by regularly doing the 5-step Mozzie Wipeout. All of us have a part to play in preventing dengue. The latest updates on the dengue situation can be found on the NEA website, stop Dengue Now Facebook page, and myENV app.
~~ End ~~
For more information, please contact us at 1800-CALL NEA (1800-2255 632) or submit your enquiries electronically via the Online Feedback Form or myENV mobile application.