After dengue cases hit a 5-year high in July with 665 cases recorded in just a week, Minister for the Environment and Water Resources revealed on Monday (2 September) that the figure has now reduced.
Speaking in Parliament, the Minister noted that the number of dengue cases has declined and majority of dengue clusters in the country are no longer labelled as hotspots. He explained that as of August 24, the National Environment Agency (NEA) has closed 863 of 1,021 clusters created in 2019, and reduced the 665 cases recorded in the second week of July to 477 cases in the third week of August.
He also added that some of the largest clusters like Woodlands, Upper Thomson, Chai Chee and Pasir Ris have closed.
Despite closing major clusters, NEA stated in its website that there are still newer larger clusters being formed at Choa Chu Kang Ave 2, Choa Chu Kang Ave 4, Jalan Eunos, Flora DR, Ang Mo Kio Ave 3 and Commonwealth Ave.
Mr Masagos said that the increase in dengue cases this year is attributed to three factors – an increase in mosquito population, the relatively warmer weather and lower herd immunity in the population.
In order to curb this, NEA has “stepped up its housekeeping measures and inspections of common areas to eliminate potential breeding areas”.
“In the first six months of the year, NEA conducted more than 442,000 inspections island-wide and uncovered about 8,200 mosquito breeding habitats. 60% of the breeding habitats were found in residential premises. In dengue clusters, the proportion of breeding habitats detected in residential premises is even higher at 70%,” said the Minister.
He added, “This points to an urgent need for home and premises owners found with mosquito breeding and has taken about 1,200 enforcement actions against households between January and June.
As such, Mr Masagos noted that mayors, grassroots advisers, community leaders as well as dengue prevention volunteers have amped-up public education campaigns as it contributed to the decrease in dengue cases and dengue clusters from its peak in July.
If that is not all, NEA has also join forces with the People’s Association (PA) on 25 August to increase dengue outreach efforts, said the Minister.
“5,000 volunteers from PA grassroots organisations and Community Emergency and Response Team will work hand-in-hand with dengue prevention volunteers to conduct house visits and distribute dengue prevention leaflets,” said Mr Masagos.
More initiatives taken
Responding to questions raised by Members of Parliament (MPs) on controlling the dengue cases, Mr Masagos said that NEA will continue to work with different partners to enhance the efforts in dengue control. One of the methods include deploying 14,000 more Gravitraps to new HDB blocks and landed estates.
Gravitrap – which attracts and traps female Aedes mosquitoes looking for areas to lay their eggs – was first introduced in 2017 and there are currently 50,000 of those in the country.
“The Gravitrap surveillance system allow NEA to prioritise its resources and deploy officers to focus on areas with high mosquito population,” said Mr Masagos.
Besides that, he also highlighted that NEA is sharing information on areas with “relatively higher Aedes aegypti adult mosquito population on its website” in order to create “awareness of dengue risk in areas with high mosquito population which might not yet be dengue clusters”.
This is done “so that stakeholders can pre-emptively take measures to reduce potential mosquito breeding habitats and avoid the formation of new dengue clusters,” said the Minister.
Project Wolbachia in Singapore
Responding to a question raised by MP Joan Pereira of Tanjong Pagar GRC on expediting the trial of Project Wolbachia in the top dengue clusters given the high success rate of this project in eradicating the Aedes mosquito populations, Mr Masagos said that although “results from Project Wolbachia field studies have been promising” but “it is important for NEA to evaluate the technology rigorously before deploying it on a large scale”.
This is because “the Wolbachia technology has only been tested in small study sites in Singapore, and remains under research and development,” the Minister explained.
For those who don’t know what this project is all about, it basically means taking male Aedes mosquitoes and infecting it with Wolbachia bacteria, so that when they mate with female Aedes mosquitoes, the female’s egg don’t hatch. On top of that, Wolbachia-infected male mosquitoes also do not bite.
“The project is now in Phase 3, which aims to determine if the Aedes aegypti population suppression achieved this far can be sustained in larger areas. The release area covers 84 blocks in Yishun and 60 blocks in Tampines and is 3.7 times larger than the release area when Wolbachia first started,” Mr Masagos said.
However, he stressed that Wolbachia technology is not a “silver bullet.
“It will not replace the community’s effort to ensure good housekeeping, which is still needed to keep our homes and estates from mosquitoes and dengue,” the Minister noted.
He added, “Comprehensive mosquito surveillance, source eradication of mosquito breeding habitats, and spraying of insecticide where necessary to control the adult mosquito population, continue to be Singapore’s key strategies for dengue prevention and control”.