Some progress has been made as largest Woodlands cluster closes and dengue transmission reduces at Chai Chee cluster, but other clusters remain a concern
Singapore, 19 July 2019 – The largest dengue cluster this year in Woodlands, with a total of 216 reported cases, has closed and is under surveillance. However, caution is needed and residents are advised to be alert to the threat of dengue as there are other clusters of concern, such as at Geylang Rd, Jln Lembah Thomson, Aljunied Rd, Pasir Ris Dr 3, Changi Rd and Jurong East Ave 1.
2 As of 18 July 2019, there were 188 active dengue clusters in Singapore. A total of 7,808 dengue cases have been reported this year (as of 18 July 2019), about five times more than the dengue cases reported in the same period last year. We are in the peak dengue season in Singapore, which usually stretches from June to October, and the region around us is similarly seeing an upsurge of dengue cases this year. Urgent community action is needed to eliminate all potential mosquito breeding habitats.
Key reasons for the high dengue cases this year
3 Based on NEA’s surveillance, data collection and analysis, the surge in dengue cases this year are attributable to a combination of three factors – increase in mosquito population, warmer weather and lowered herd immunity. The Gravitrap surveillance system deployed by NEA has shown an increase in the Aedes aegypti mosquito population by almost three times since the last major dengue outbreak in 2013. This persistently high Aedes aegypti mosquito population increases the risk of transmission of the dengue virus. In addition, the mean temperature for the first half of this year was 0.7 degrees higher than that during the same period last year. Warmer temperatures result in higher transmission of dengue due to the accelerated development of the Aedes mosquito and shorter incubation period of the dengue virus. At the same time, a large proportion of our population continues to be susceptible to dengue, given our population’s low herd immunity. The proportion of adults that have had dengue before has progressively reduced from 59 per cent in 2004, to 51 per cent in 2009, and 41 per cent in 2017.
Largest Woodlands cluster closes and fewer cases reported at Chai Chee cluster
4 The largest Woodlands cluster, with a total of 216 reported cases, has closed and is under surveillance. The cluster was located at Woodlands Ave 6 / Woodlands Circle / Woodlands Cres / Woodlands Dr 40 / Woodlands Dr 60 / Woodlands Dr 70 / Woodlands Dr 72. We have observed a slowing down in dengue transmission in the past seven weeks at this cluster, with no reported cases in the past two weeks, compared to 27 cases reported in a week when transmission was at its peak.
5 The rate of dengue transmission has also slowed down at the Chai Chee cluster – at Chai Chee Ave / Chai Chee Dr / Chai Chee Ln / Chai Chee Rd / Chai Chee St. As of 18 July 2019, a total of 130 cases were reported. Of these, seven cases were reported in the past two weeks, compared to 26 cases reported in a week during the peak transmission period.
6 Despite the slowdown in the number of cases reported and the progress made, all stakeholders and residents in these clusters cannot be complacent and must remain vigilant in eradicating possible mosquito breeding habitats. Woodlands is also still under surveillance and cases may resurface given the mobility of our population.
Ongoing transmission at Geylang Rd, Jln Lembah Thomson, Aljunied Rd, Pasir Ris Dr 3, Changi Rd and Jurong East Ave 1
7 Large clusters at Geylang Rd and Jln Lembah Thomson have seen 11 and 10 cases reported in the past two weeks, respectively. While these have come down compared to the past weeks, the transmission in these two areas remains persistent, although at a lower case level. With the general uptrend in dengue cases across the island, a relatively faster rate of dengue transmission has also been observed at Aljunied Rd, Pasir Ris Dr 3, Changi Rd and Jurong East Ave 1. The majority of mosquito breeding habitats found in most of these clusters are within residential premises (refer to Annex A for inspection findings at the largest dengue cluster areas).
8 NEA and Town Councils have stepped up inspections and all stakeholders at the cluster areas need to step up their efforts to stem dengue transmission. All residents living in cluster areas are strongly encouraged to cooperate with NEA officers, and facilitate their checks and indoor misting in their homes. As the Aedes aegypti mosquito has adapted well to the urban environment, it is critical to eradicate mosquito breeding habitats and adult mosquitoes. Adult Aedes mosquitoes tend to rest inside homes. Accessing all homes in a dengue cluster area as quickly as possible, with the help of the local Grassroots and residents, helps keep the community safe. Residents living in cluster areas are also strongly encouraged to protect themselves, by applying mosquito repellent regularly, and keeping their homes free of stagnant water.
Concerted efforts to stem dengue transmission
9 All stakeholders need to reduce the mosquito population urgently. NEA, together with other Government agencies from the Inter-Agency Dengue Task Force, as well as all Town Councils, are continuing to check public areas and housing estates for potential mosquito breeding habitats, with officers carrying out daily checks. We are also eliminating adult mosquitoes through measures such as space-spraying and the deployment of Gravitraps.
10 Between January and June 2019, more than 442,000 inspections were conducted islandwide, and NEA uncovered about 8,200 mosquito breeding habitats. To safeguard public health, NEA will not hesitate to take enforcement action against anyone found to have created conditions favourable for the propagation or harbouring of vectors. As of June 2019, about 1,200 [1] enforcement actions have been taken against households for mosquito breeding.
11 Following this year’s national dengue campaign launch on 7 April 2019, 89 divisions across Singapore have organised more than 440 dengue prevention events and activities. Mayors, Grassroots Advisers, Community Leaders and Dengue Prevention Volunteers (DPVs) have been visiting residents’ homes to share dengue prevention tips, including information on how to identify potential mosquito breeding habitats. To heighten the public’s awareness and vigilance against mosquito breeding and dengue, particularly in dengue cluster areas, NEA will continue to work with stakeholders to carry out community events and house visits, to remind residents to regularly practise the 5-step Mozzie Wipeout.
12 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 dengue transmission cycle, by regularly doing the 5-step Mozzie Wipeout. All of us, including residents, contractors and business owners, 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.
[1] Provisional figures as of 11 July 2019
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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.
ANNEX A
Inspection Findings At Current Largest Dengue Clusters
(Information as of 18 July 2019)
The national average of mosquito breeding detected in homes is 60 per cent.
S/No. | Cluster Locality | No. of Cases | Date of Notification | Proportion of Mosquito Breeding in Homes |
1 | Woodlands Ave 6 / Circle / Cres / Dr 40 / Dr 60 / Dr 70 / Dr 72 | 216 | 2 Apr 2019 | 87% |
2 | Geylang Rd / Guillemard Rd / Lor 4, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23 Geylang / Sims Ave / Westerhout Rd | 174 | 26 Apr 2019 | 72% |
3 | Chai Chee Ave / Chai Chee Dr / Chai Chee Ln / Chai Chee Rd / Chai Chee St | 130 | 30 Apr 2019 | 76% |
4 | Jln Lembah Thomson / Jln Pelatina / Soo Chow Dr / Soo Chow Gdn Rd / Soo Chow Rise / Soo Chow View / Soo Chow Way / Taman Permata / Thomson Ridge / Upp Thomson Rd | 129 | 3 May 2019 | 80% |
5 | Pasir Ris Dr 3 / Pasir Ris Dr 4 / Pasir Ris Dr 6 / Pasir Ris St 41 | 98 | 11 Jun 2019 | 47% |
6 | Aljunied Rd / Geylang Rd / Guillemard Rd / Jln Molek, Suka / Lor 22, 24, 25, 25A, 26, 27, 27A, 28, 29, 30, 31, 32, 33, 34, 35, 36 Geylang / Sims Ave | 96 | 26 Apr 2019 | 67% |
7 | Changi Rd / Joo Chiat Ave / Joo Chiat Pl / Joo Chiat Walk / Lor G Telok Kurau / Lor G Telok Kurau (East Bay Gdns) / Lor H Telok Kurau / Lor J Telok Kurau / Lor K Telok Kurau | 68 | 29 May 2019 | 60% |
8 | Jurong East Ave 1 / Jurong East St 21 / Jurong East St 24 | 66 | 22 May 2019 | 46% |