Dengue cases up 53 per cent between July and September, one death reported
There was a total of 3,055 reported dengue cases for the July to September period, a 53 per cent increase from the previous quarter.
There was one death due to infection during that period, bringing the number of dengue-related deaths to three in 2023, according to data from the National Environment Agency (NEA).
As at Nov 4, there were 8,437 cases reported so far in 2023 – about a quarter of the 32,325 cases recorded in 2022.
NEA figures, released on Oct 31, showed that the DenV-2 serotype accounted for 67.9 per cent of the infections in September.
This is in contrast to June and August, when the DenV-1 strain was dominant.
DenV-1 caused a major outbreak 10 years ago, with 22,170 dengue cases reported in 2013.
It replaced the DenV-3 strain that drove the dengue outbreak in 2022 and was the main cause of infections in the first half of 2023.
Of the four distinct dengue virus variations, the DenV-1 and DenV-2 serotypes are most commonly seen here.
The majority of infections since 2016 have been caused by DenV-2.
Dengue expert Tikki Pang told The Straits Times the increase in cases could be down to a number of factors, such as increased rainfall together with higher temperatures due to the El Nino phenomenon, and an increase in mosquito numbers due to these favourable breeding conditions.
In October, the NEA had warned that warmer weather in the coming months due to El Nino – a climate pattern associated with the unusual warming of surface waters in the eastern tropical Pacific Ocean – could see the dengue situation becoming worse.
However, there is “no real cause for concern” with the re-emergence of the DenV-2 serotype, said Professor Pang, a visiting professor at the National University of Singapore’s Yong Loo Lin School of Medicine
He said there that from time to time, different strains will become dominant.
The resurgence of DenV-2 cases may be due to people having waning immunity against the strain, as DenV-3 was the predominant serotype in the first half of the year, he said.
It is “definitely possible” that there could be a surge in dengue cases at the end of this year or the beginning of 2024 due to the different factors at play, he added.
To avoid getting infected, people should use mosquito repellent, wear long sleeves and get vaccinated, if eligible, said Prof Pang.
The NEA identified 290 dengue clusters between July and September 2023, an increase of about 36 per cent compared to the previous quarter.
Of these, 219 have been closed.
The agency also discovered about 4,500 mosquito breeding habitats during that period, a decrease of about 15 per cent compared to the previous quarter.