Dengue cases this year hit 3-year high

A larvasonic system - which generates soundwaves to cause mosquito larvae to rupture - being deployed at a waste water treatment tank at the worksite of the upcoming Tanjong Katong MRT station yesterday. ST PHOTOS: DESMOND FOO
A larvasonic system - which generates soundwaves to cause mosquito larvae to rupture - being deployed at a waste water treatment tank at the worksite of the upcoming Tanjong Katong MRT station yesterday. ST PHOTO: DESMOND FOO
A construction worker using a phone app to monitor the mosquito population in a Gravitrap cylinder at the Tanjong Katong MRT station worksite yesterday.
A construction worker using a phone app to monitor the mosquito population in a Gravitrap cylinder at the Tanjong Katong MRT station worksite yesterday.ST PHOTO: DESMOND FOO

This is despite fall in weekly dengue cases and NEA closing most clusters since start of year

Almost 230 dengue clusters were closed in the last month alone, although the total number of dengue cases has risen from a month ago.

A total of 12,108 dengue cases for this year were reported as of Sept 21, up by 1,360 from 10,748 cases as of Aug 24.

This is the highest number of cases reported in three years.

However, the number of weekly cases has continued to fall, to 303 in the third week of September, down from 480 a month before.

As of Wednesday, the National Environment Agency (NEA) had closed 1,092 of the 1,183 dengue clusters since the start of this year.

A cluster is closed if no new case is reported for 14 days from the symptom onset date of the latest case.

But with dengue season still at its height, and cases of Zika creeping up, the NEA said there can be no let-up in efforts to keep mosquitoes at bay. "We're clearly not out of the woods yet," said the NEA's director-general of public health Chew Ming Fai yesterday.

THREAT STILL PRESENT

We do need residents to step up... Most of the breeding is still taking place in homes. The five-step Mozzie Wipeout is important, (and so is) letting your friends and neighbours know the threat is not over and reminding them to clear the area of stagnant water.

MR CHEW MING FAI, NEA's director-general of public health.

"The peak dengue season in Singapore usually lasts from June to October, and the weather remains quite warm," he said.

He was speaking during a tour of the construction site for the future Tanjong Katong MRT station.

 
 
 

The largest dengue cluster is in Jalan Eunos, with 127 cases, followed closely by Choa Chu Kang Avenue 2, where there have been 126 cases.

Separately, four cases of Zika were reported between Sept 8 and 21, bringing the total number of such cases this year to 11.

While some may pin the blame for rising dengue figures on construction sites, the NEA's data shows that the bulk of mosquito breeding habitats detected - about 60 per cent - were found in residential premises.

Mr Chew said: "We do need residents to step up... Most of the breeding is still taking place in homes. The five-step Mozzie Wipeout is important, (and so is) letting your friends and neighbours know the threat is not over and reminding them to clear the area of stagnant water."

The NEA has also stepped up its inspection of construction sites.

From January to June, the NEA conducted around 3,400 inspections at construction sites, issued 230 notices to attend court and 17 stop-work orders, and taken 11 court prosecutions against contractors for repeat offences.

During the same period, 12 dengue clusters were linked to construction sites, while 22 construction workers were infected with the virus.

However, after working with Singapore Contractors Association Limited and others in the industry, the agency has seen the proportion of construction sites breeding mosquitoes fall to 6 per cent this year - from 11 per cent of the sites inspected in 2013.

Anti-mosquito measures have been put in place at the Tanjong Katong construction site in accordance with the Land Transport Authority's requirements. These include daily housekeeping efforts to prevent stagnant water from accumulating, daily temperature-taking for workers, and monitoring of the mosquito population using Gravitraps - small black cylinders that trap female Aedes aegypti mosquitoes looking for water surfaces to lay eggs on.

Woh Hup, the firm overseeing the construction, has taken additional steps such as issuing its workers and staff with mosquito-repellent vests and deploying soundwave-emitting devices to destroy mosquito larvae.

Tanjong Katong MRT station's project director Thambithurai Vasudevan, who is from Woh Hup, said: "We need to take care of our workers and our staff - this is a core value for our company."

A version of this article appeared in the print edition of The Straits Times on September 27, 2019, with the headline 'Dengue cases this year hit 3-year high'. Print Edition | Subscribe