Warmer temperatures enhance the growth of mosquito larvae and cause them to grow into adult mosquitoes faster, said Assistant Professor Vincent Pang, Director, Centre for Infectious Disease Epidemiology and Research (CIDER).
“Some studies showed that warmer temperatures may also increase the number of eggs laid per mosquito,” he added.
In addition to hot weather and the increase in Aedes mosquito population, low herd immunity could also be one of the main reasons for the spike in cases this year.
Professor Leo Yee Sin, Executive Director of the National Centre for Infectious Diseases and Adjunct Professor at SSHSPH, said the low herd immunity can be partly attributed to the successful implementation of the Aedes control programme in the 1970s and 1980s.
There are four known strains of dengue in Singapore: Dengue-2 has been the predominant serotype since 2016. Dengue-1 was the predominant serotype in the 2004 to 2005 and 2013 to 2014 outbreaks.
“The progressive build-up of new residents over the years, with limited or no prior exposure to the predominant serotypes Dengue-1 and Dengue-2 and who would be susceptible to dengue infection, may contribute to the overall low herd immunity,” said Dr Pang.
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