Singapore is currently grappling with a worrying increase in dengue cases, with over 7,000 reported so far in 2023. The resurgence of the DenV-1 dengue virus strain, which caused a major outbreak a decade ago, has raised concerns among health authorities. The National Environment Agency (NEA) has reported that the number of active dengue clusters has risen to over 60, with nine clusters classified as red-alert. Local media reports suggest that the situation may worsen as the year progresses. However, local authorities have been proactive in addressing the rising cases and have implemented effective strategies to control the situation.
Last year, Singapore recorded more than 32,000 dengue cases, marking the second-highest number ever reported. The resurgence of the DenV-1 strain, which caused a major outbreak in 2013, is particularly concerning. Over time, the population’s immunity to this strain has decreased, making them more susceptible to infection.
The DenV-1 dengue virus strain has become a significant cause for concern among health authorities in Singapore. NEA has noted that this strain has been contributing to persistent dengue transmission since June 2023. With the rise in DenV-1 cases and a high Aedes aegypti mosquito population, Singapore is at risk of experiencing sustained high levels of dengue transmission, especially during the warmer months from May to October.
The prevalence of different dengue virus serotypes can shift over time due to various factors. Historically, DenV-1 and DenV-2 were dominant, but in late 2021, the rarer DenV-3 serotype became prevalent. However, in July, the proportion of DenV-1 cases surged to about 55%, surpassing DenV-3 cases. Given Singapore’s status as a global travel hub, it is challenging to predict which serotype will dominate in the future.
Infectious diseases experts suggest that while more of the population in Singapore will eventually develop immunity to DenV-1, it may take time. DenV-1 is expected to remain the dominant strain for a few years, potentially leading to another outbreak.
The largest dengue cluster in Singapore is currently located in Lorong 1 and Lorong 2 Toa Payoh, with 323 cases. Despite efforts to control the mosquito population, dengue transmission continues. Authorities have been implementing vector-control measures, including inspections, drain maintenance, and fogging.
In light of the concerning surge in dengue cases driven by the resurgence of the DenV-1 dengue virus strain and a high Aedes mosquito population, vigilance, community involvement, and ongoing efforts to control mosquito breeding are crucial to mitigate the impact of dengue in Singapore.