SINGAPORE - Those who have been infected with dengue are urged to protect themselves against mosquito bites to help curb the spread of the disease, as Singapore grapples with a surge of over 5,000 dengue cases in the first quarter of 2024 – more than double the number of cases in the same period in 2023.

As at March 25, seven people have died of dengue so far in 2024, said the National Environment Agency (NEA). 

Ahead of the traditional peak dengue season of May to October, Senior Parliamentary Secretary for Sustainability and the Environment Baey Yam Keng launched the National Dengue Prevention Campaign 2024 in Bukit Batok on March 31. The campaign aims to get the community to stay vigilant and help reduce the risk of dengue infection.

Speaking to reporters, Mr Baey said: “Last year, 2023, was actually a good year... for dengue cases. We had about 9,900 cases. That was almost 70 per cent less than the previous outbreak year (in 2022). But what’s worrying is that this year, we are seeing an increase in the number of cases.”

In 2023, the number of dengue cases stood at 9,949 – a 69 per cent drop from the 32,173 cases in 2022. There were six deaths in 2023, and 19 deaths in 2022.

Weekly reported dengue cases in 2024, on average, have been more than 300 from mid-February, although there was a slight dip to 222 cases for the week of March 24 to 28, according to NEA’s website.

Dengue patients, too, can do their part in stopping the transmission of the dengue virus by taking precautions to avoid further mosquito bites – these include spraying insecticide in dark corners around their house, applying insect repellent regularly, and wearing long-sleeved tops and long pants, Mr Baey added. 

Mosquitoes become infected when they bite a person infected with the dengue virus. Infected mosquitoes can then spread the virus to other people by biting them.

NEA is working with the Ministry of Health, polyclinics and general practitioner clinics to spread these messages and remind patients who are recovering from dengue to take these precautions, said Mr Baey.

This comes as most of the seven people who died of dengue in 2024 were elderly folk, who are more vulnerable to dengue to begin with, he noted.

“We need to be more mindful because of the ageing population, and we hope that everyone can look out for mosquito breeding and stop the spread of dengue,” he said.

Elderly people are at high risk of more severe illness and death from dengue, especially if they are grappling with other chronic conditions at the same time.

Dr Jacky Shee, a family physician at Healthway Medical clinic in Bukit Batok, said he has seen an increase of 20 per cent to 30 per cent of dengue cases in 2024 compared with 2023. Many have symptoms such as fever and body aches, which resolve on their own, and those with more serious illness tend to be the elderly.

Singapore managed to avert a dengue outbreak in 2023 through stepped-up prevention and control measures, despite there being high-risk factors, such as a high Aedes aegypti mosquito population and low population immunity against the virus.

Some of these measures included removing stagnant water, intensified vector control measures and increased public communication efforts, said NEA.

The same risk factors for a dengue outbreak remain, explaining the unusually high number of cases in 2024.

Mr Baey said: “There’s nothing we can do about herd immunity, but what we can do is to reduce the Aedes mosquito population... and that’s where everyone can play a part to support the (dengue prevention) campaign, not just during this campaign period, but throughout the year.”

NEA said nationwide outreach will be conducted over at least three months to sustain awareness throughout the traditional peak dengue season.

There are four dengue serotypes. The current dominant one is Den-2, which gained dominance in September 2023. Den-3 was dominant from 2021 to mid-2023, when Den-1 prevailed for a few months. People do not get reinfected by the same serotype, but can be infected by the other three.

NEA said it will also continue to combat dengue with Project Wolbachia, and has expanded the project to five additional residential sites, increasing coverage from 350,000 households in 2023, to 480,000 households by the first quarter of 2024.

These sites – Bukit Merah-Telok Blangah, Clementi-West Coast, Commonwealth, Holland and Marine Parade-Mountbatten – were chosen based on historical dengue risk.

Under Project Wolbachia, lab-grown male Wolbachia mosquitoes that mate with female Aedes mosquitoes result in eggs that cannot be fertilised, thus helping to reduce the Aedes mosquito population.

In Bukit Batok, Tampines, Choa Chu Kang and Yishun, there has been more than a 90 per cent reduction in the Aedes mosquito population.  

Data from 2019 to 2022 also indicates that residents living in areas with at least one year of mosquito releases are up to 77 per cent less likely to be infected with dengue, said NEA. 

Mr Baey said: “Regular mosquito releases could help mitigate dengue outbreaks at these areas, complementing community efforts to prevent mosquito breeding.” 

In the Year of Public Hygiene, which places strong emphasis on the collective efforts of all stakeholders to uphold high standards of public hygiene, all stakeholders are reminded that they have a critical role to play in dengue prevention and control, said NEA.