Amid a record year for dengue infections globally, a new study has found that climate change is responsible for 19% of the rising dengue burden.
Climate change has the potential to trigger an additional 40-60% increase by 2050 — and up to 150-200% in some areas — according to the study presented at the annual meeting of the American Society of Tropical Medicine and Hygiene (ASTMH) in the US.
India has also seen a surge in dengue cases this year.
The latest findings from researchers at Stanford and Harvard universities offer the most definitive evidence to date that climate change is a major factor driving the global surge in the mosquito-borne disease.
Countries in the Americas alone have recorded almost 12 million cases in 2024, compared to 4.6 million in 2023, with locally acquired infections reported in California and Florida. The study also carries warnings of even sharper increases to come.
“We looked at data on dengue incidence and climate variation across 21 countries in Asia and the Americas and found a clear and direct relationship between rising temperatures and rising infections,” said Erin Mordecai, an infectious disease ecologist at Stanford’s Woods Institute for the Environment.
It’s evidence that climate change has already become a significant threat to human health, and for dengue in particular, our data suggests the impact could get much worse, Mordecai added.
While some dengue infections produce only mild symptoms, others cause excruciating joint pain (earning dengue the nickname “breakbone fever”), and severe cases can lead to bleeding complications and shock.
There are no drugs to treat the disease, and while there are two licensed dengue vaccines available, some experts have pointed to challenges with both that could limit widespread adoption.
The study finds that amid dengue’s growing threat, moderating global warming by reducing emissions would also moderate the climate impacts on dengue infections.
The analysis shows that with sharp cuts in emissions, areas now on track to experience a 60% increase would instead see about a 40% rise in dengue infections between now and 2050.
However, with global climate models predicting that temperatures will continue to rise even with large reductions in emissions, the researchers found that 17 of the 21 countries studied would still experience climate-driven increases in dengue, even under the most optimistic scenarios for carbon cuts.
Mordecai said that dengue-endemic areas that are just now entering the 20 to 29 degrees Celsius “sweet spot” for virus transmission — parts of Peru, Mexico, Bolivia, and Brazil — could face the biggest future risks, with infections over the next few decades rising by 150% to 200%.
(ians)
