Indonesia’s dengue cycle is shortening as climate shifts, official warns

The Indonesian Health Ministry has said climate change is playing a major role in the rising number of dengue hemorrhagic fever (DBD) cases across the country. Higher global temperatures — including those driven by El Niño — are making Aedes aegypti mosquitoes more active and aggressive, increasing the risk of dengue transmission to humans.

dr. Fadjar SM Silalahi, head of the Health Ministry’s working team on vector-borne diseases, zoonoses, venomous animal bites and toxic plants, said climate change is creating conditions that favor Aedes aegypti, the primary dengue vector. Warmer temperatures, he said, prompt mosquitoes to bite more frequently because they require more blood to reproduce.

“Mosquitoes bite more often because they need blood for reproduction. As a result, the potential for transmission to humans becomes much higher, and the mosquito population also increases,” Fadjar said during a media discussion in Cikini, Central Jakarta, on Wednesday (Feb. 4, 2026).

He said spikes in dengue cases typically occur after an increase in the Oceanic Niño Index (ONI), which indicates an El Niño event. This pattern was reflected in 2024, which was recorded as Indonesia’s hottest year on record, with the national average temperature reaching $27.5$ degrees Celsius.

In 2024, dengue cases in Indonesia hit a record 257,271, with 1,461 deaths, and were reported in every province. Cases also surged globally, with around 14 million reported infections, including 7 million confirmed cases and roughly 10,000 deaths worldwide.

“Every time El Niño is high, dengue cases also rise. This shows that the influence of climate on the increase in dengue cases is very, very significant,” he said.

According to Fadjar, climate change is also altering Indonesia’s dengue cycle. If dengue outbreaks were once believed to follow a five-year cycle, he said, that cycle is now shortening to roughly every two years.

“Now we can no longer think the way we used to — that cases will fall and it will still be a long time before they rise again. Changing climate patterns mean dengue risk continues to increase every year,” he said.

Fadjar also warned the public to stay alert during the rainy season, which can trigger a rise in dengue cases. Heavy rainfall can increase the number of breeding sites for Aedes aegypti, raising the likelihood of dengue transmission.

“Climate change and the rainy season go hand in hand — it’s a happy time for dengue mosquitoes. That’s why we must remain vigilant and keep up prevention efforts,” he said.

To prevent dengue, he urged the public to practice “3M Plus”: draining water containers, tightly covering water storage, and recycling unused items — plus additional measures to eliminate mosquito breeding sites. Dengue vaccination is also an important part of a comprehensive prevention strategy, to be implemented alongside core steps such as 3M Plus and vector control.

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