Singapore reports nearly 3,000 dengue cases in first seven weeks, Boon Lay Place monitored for potential Zika transmission

Dengue

From the beginning of the year through February 22, the Singapore National Environment Agency (NEA) has reported 2,970 cumulative dengue fever cases.

The weekly number of reported dengue cases remains high and is more than double the number of cases reported in Dec 2023. Collective community action and vigilance are critical to help prevent a surge in dengue cases. NEA urges residents living in dengue cluster areas to take immediate action to suppress the Aedes mosquito population and help break disease transmission, and to cooperate with NEA officers during our inspection rounds.

Image/by Monika Neumann from Pixabay , CDC

There are four Dengue virus serotypes circulating in Singapore. Currently, Dengue virus serotype 2 (DENV-2) has been predominant since Sep 2023, with prior periodic dominance of DENV-1 and DENV-3 in 2023. Our population’s immunity to all four Dengue virus serotypes remains low.

The NEA announced this week they will be expanding Project Wolbachia – Singapore to five additional sites in February 2024, covering 130,000 more households and bringing total coverage to 35% of all Singapore households. Results indicated more than 90% reduction in the Aedes aegypti mosquito population and up to 77% are less likely to get dengue at release areas.

This will increase Wolbachia coverage from 350,000 to 480,000 households – an increase from 26 per cent to 35 per cent of all households in Singapore.

The five locations are Bukit Merah – Telok Blangah, Clementi – West Coast, Commonwealth, Holland, Marine Parade – Mountbatten.

Dengue mosquito populations in the existing study sites of Bukit Batok, Choa Chu Kang, Tampines and Yishun have generally fallen by more than 90 per cent. In the last 4 years (2019 to 2022), residents living in areas with at least one year of releases were up to 77 per cent less likely to be infected with dengue.

Zika

Three Zika cases have been reported nationally in 2024 to date with the no new cases being reported in Singapore since 8 February 2024.

The Ministry of Health and NEA announced they are closely monitoring Boon Lay Place for potential Zika transmission. 

While there have been no more Zika cases reported in this area since December 2023, enhanced surveillance involving mosquito and wastewater testing has revealed persistent Zika virus signals in the area, which suggests ongoing Zika transmission.

MOH has alerted doctors to be vigilant and to test for Zika among patients with clinically compatible symptoms, especially for individuals residing or working in the Boon Lay area. 

Residents in and around the Boon Lay Place area are advised, especially pregnant women, to protect themselves and monitor their health closely. They should seek medical attention if unwell with Zika virus infection symptoms, which include rashes, fever, joint pain, muscle pain, headache and/or conjunctivitis (red eye). They should also inform their doctors of the location of their residence and workplace. 

 Symptoms of Zika virus infection include rashes, fever, joint pain, muscle pain, headache and/or conjunctivitis (red eyes). However, most people infected with the Zika virus infection may not develop symptoms. Although rare, Zika virus infection can cause microcephaly in unborn babies of pregnant women. There are no vaccines or specific anti-viral drugs against Zika virus infection.

Residents, especially those residing at Zika and dengue cluster areas, are reminded to prevent mosquito bites with the ‘S-A-W’ actions to protect themselves and their loved ones:

• Spray insecticide in dark corners around the house
• Apply insect repellent regularly, with DEET, picaridin or IR3535 as the active ingredient
• Wear long-sleeve tops and long pants 

Other measures include enclosing rooms or installing wire-mesh mosquito screens to prevent entry of mosquitoes. 

Persons with Zika virus infection are also advised to take these protection measures against mosquito bites to prevent further spread. Infected men should practice safe sex or abstain from sex for at least three months after recovery to prevent sexual transmission of the Zika virus.  If a woman is confirmed positive for Zika, she should practice safe sex or abstain from sexual intercourse for at least two months after recovery, before trying to conceive.