Global Dengue Cases Doubled In 2024 From 2023 To 12 Million; Study Links Surge To Extreme Rain From Climate Breakdown
Every year, mosquitoes in mostly tropical and subtropical countries cause millions of cases of dengue fever, a virus that induces potentially lethal flu-like symptoms. Cases surged in 2019, after rising for decades, making dengue one of the World Health Organization’s top-10 global health threats and the fastest-growing mosquito-borne disease. In 2023, 6.5 million people contracted dengue and more than 6,800 people died in what was the largest outbreak of the disease ever recorded—until the following year, when cases doubled. South America saw record outbreaks in both years, with hotspots in Brazil and Peru. Many factors may have contributed to these grim milestones, the WHO concluded, including a strong El Niño, when warmer ocean waters can trigger heavy rains and flooding in the tropics.
Now, a new study has harnessed a relatively new modeling method to determine whether the catastrophic cyclone that pummeled the normally dry northwestern coast of Peru in 2023 helped drive the historic outbreak of dengue fever that killed more than 380 people in six months. In the study, published Tuesday in the peer-reviewed journal One Earth, a team of scientists from the United States, Peru and Ecuador attributed 60 percent of dengue cases over nearly three months in the most affected regions to the relentless, torrential rains brought by Cyclone Yaku and a strong El Niño.
The study, among the first to estimate the number of mosquito-borne illness cases caused by extreme weather, suggests that climate change made those conditions more likely. Climate change, the team concluded, “has increased the risk of warm and unusually wet conditions in northwestern Peru, which in turn caused the majority of cases during an unprecedented dengue outbreak even after controlling for region-wide increases in dengue.” “People already thought there was a contribution of climate, but I didn’t necessarily expect it to be 60 percent (of cases),” said Mallory Harris, a postdoctoral scholar at the University of Maryland who led the research while getting her Ph.D. at Stanford University. “The magnitude did surprise me.”
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They identified the regions with the most extreme precipitation and compared them with areas less affected by the cyclone, choosing regions with the most historically similar climate conditions before the cyclone as control groups. Then they used the method to determine what share of the outbreak could be attributed to the extraordinarily wet conditions by estimating how many cases might have occurred without the cyclone.“We predict that it would have been one of the worst years ever for dengue, regardless,” Harris said. “But then this cyclone, this extreme precipitation, is what really kind of supercharged it to where you could get this tenfold higher (case rate) than the historic average.”
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https://insideclimatenews.org/news/20032026/peru-dengue-fever-record-outbreak-climate-driven-weather/
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