There were 377 dengue cases reported last week, the highest weekly total this year, the National Environment Agency (NEA) said yesterday.
The end of the year usually sees fewer infections, but cases have been on an unusual rise in recent months. A weekly high of 361 was reported just two weeks ago.
In a Facebook post yesterday, Senior Minister of State for Health and the Environment and Water Resources Amy Khor warned the public to "stay vigilant against dengue".
The NEA said warmer than usual year-end weather caused by the El Nino phenomenon could result in shorter mosquito breeding periods and shorter incubation times for the dengue virus.
While the number of dengue cases in the first 10 months of this year fell by about half compared with the same period last year, the Aedes mosquito population has doubled.
The DENV-2 serotype, which had been the dominant strain before 2013 until it was replaced by DENV-1, has now returned.
Dengue cases due to the DENV-2 serotype have increased, accounting for more than half of all cases here, according to the NEA.
Weekly numbers of more than 800 have been seen at times in 2013 and last year.
But this recent surge is worrying as a change in the main circulating dengue virus may be an early indicator of a future outbreak, unless measures are taken to suppress the Aedes mosquito population.
There are four strains of dengue and getting infected with one does not mean you are immune to the others. Many people infected recently could become infected again with a new strain.
Dr Khor urged the public to work together to "deny the Aedes mosquitoes their breeding habitats".
There were 75 active dengue clusters as of Monday, with 152 cases recorded in the largest cluster of Tampines Avenue 3 and Avenue 4, and Tampines Street 81 and Street 91.
Four people have died of dengue fever this year - three in recent months.
On Dec 9, a 59-year-old woman who lived in Upper Thomson died at Khoo Teck Puat Hospital. On Nov 28, a 79-year-old man died a few days after being admitted to Tan Tock Seng Hospital. The other victims were a 60-year-old woman from India who was visiting her son here in September, and a 53-year-old woman from China who died in February.
A total of 10,142 dengue cases were reported as of Dec 12. In the whole of last year, there were 18,335 cases with five deaths. The NEA said people infected with dengue should apply mosquito repellent to prevent mosquitoes from biting them and infecting others, and that those with symptoms should consult a doctor.
Members of the public are also advised to practise the "five-step mozzie wipeout", referring to actions to remove stagnant water to prevent mosquito breeding. These include inverting buckets and plant pot plates, and regularly changing water in vases.
This article was first published on Dec 30, 2015.
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