More than 7,100 people have been infected with dengue so far this year - and more than 1,000 have needed to be hospitalised, new official figures reveal.
With the onset of the hotter months from June to October, the number of infections has been rising steadily, and there are now 63 active dengue clusters.
Last week, 461 people were diagnosed, and since Sunday, another 216 have fallen ill. Doctors have to report all dengue cases so that efforts can be made to prevent further transmission.
There is a cluster concentration in the Serangoon-Hougang area, with the cluster between Aroozoo Avenue and Lorong Ah Soo the biggest at 140 cases. Some 24 new cases have been reported there in the past fortnight.
There are four strains of dengue virus. The dominant one is currently Den-1, the same one that caused an epidemic last year that infected 22,170 people and killed seven.
The National Environment Agency said on its dengue website: "A large proportion of our population is still susceptible to dengue infection due to the lack of immunity."
Dengue is spread by the Aedes mosquito. Someone who has been infected once is protected against that strain, but can fall ill again if they are bitten by a mosquito carrying a different dengue strain.
Fewer than one in five people with dengue ends up in hospital. Although the number of cases is currently high, a Ministry of Health spokesman said that dengue patients on any one day occupy "well under 1 per cent" of beds in acute public hospitals.
Singapore hospitals are facing a massive bed crunch, with above 90 per cent occupancy rates.
Neighbouring Malaysia is experiencing a dengue outbreak that has seen 33,500 infections in the first five months of this year - more than triple the number for the same period last year - and that has killed 68.
Asean Dengue Day will take place on Sunday in the Philippines, which has seen 22,000 infections in the first five months.
The annual event is attended by scientists and officials from member nations in an effort to highlight the problem, curb its spread and share success stories.
Vietnam, for example, is experimenting with the Wolbachia bacteria which, when introduced to the Aedes mosquito, reduces its lifespan and fertility.