Dengue cases from July to Sept fall more than 35% from previous quarter

There were 874 dengue cases here between July and September, a 35.8 per cent decrease from the 1,361 cases reported in the previous quarter.

There was one death in the latest quarter compared with two in the previous three months, according to the National Environment Agency's (NEA) quarterly dengue surveillance data released on Oct 21.

Also, the agency identified 80 dengue clusters from July to September, a 37 per cent decrease from the clusters identified from April to June. Among the 80 clusters identified, 72 were closed in the same period.

There was also a decrease in the number of mosquito breeding habitats detected by NEA in the latest quarter - the over 3,700 habitats discovered marked a decrease of about 34 per cent compared with the previous three months.

Overall, there are fewer dengue cases in 2025 up till Oct 11, compared with the same period in 2024 - 3,527 in 2025 versus 12,476 in 2024, according to the latest Health Ministry weekly infectious disease bulletin.

NEA previously said that the warmer months from May to October usually see higher dengue transmission in Singapore, due to accelerated development of the Aedes mosquito vector and faster multiplication of the dengue virus in mosquitoes.

Infectious diseases expert Ooi Eng Eong welcomed the declining trend of dengue cases and attributed the drop to several factors, such as NEA's efforts in combating dengue.

Among the agency's efforts is Project Wolbachia, which lowered the risk of contracting dengue by about 75 per cent in areas where Wolbachia mosquitoes were released.

The project, which began in 2016, is named after the Wolbachia bacteria introduced to male mosquitoes in the lab, which are then released into different areas. When female mosquitoes in the environment mate with these mosquitoes, their eggs do not hatch.

Professor Ooi, who is with the Duke-NUS Medical School, said that the level of immunity in Singapore's population to the types of dengue viruses circulating here could also explain why there has been a quarter-on-quarter fall in the number of dengue cases.

He added that the genetic composition of dengue viruses are also important in shaping the rate of such cases, as they determine how transmissible the viruses are by Aedes mosquitoes here and if they are "sufficiently fit" to infect people.

He added: "Genetic changes in dengue viruses, which happen constantly all over the world, are beyond our control and can have profound effects on where and when dengue outbreaks occur."

The drop in dengue cases in Singapore is contrasted by a surge in such cases in other countries in the region recently.

In Hanoi, prolonged heavy rain in October heightened the risk of dengue fever, prompting increased monitoring and hospital admissions.

According to the Hanoi Centre for Disease Control, the Vietnamese capital recorded 336 dengue fever cases in the week before Oct 15. Seventeen new outbreak clusters were detected, while 30 active dengue clusters are still being monitored across the city.

Bangladeshi health experts had, in early October, warned the dengue outbreak there could spiral if urgent and coordinated mosquito control efforts are not launched.

According to the Bangladeshi Directorate General of Health Services, 50,689 dengue cases and 215 deaths have been reported nationwide in 2025 as at Oct 6.