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Whether it’s stress and uncertainty from forced displacements from wildfires, rises in sea level, or fear and hunger from poor nutrition in places where people can’t grow food, climate change is one of Earth’s biggest threats. Indeed, recent scientific discoveries show that mosquito-induced dengue cases are set to double in the next 25 years, especially in warmer areas like the Americas and Asia, and could potentially affect over 250 million people. 

 “It’s evidence that climate change already has become a significant threat to human health and, for dengue in particular, our data suggests the impact could get much worse,” says Dr Erin Mordecai, an infectious disease ecologist at Stanford University. 

According to  the World Health Organisation, the global public health agency for the United Nations, dengue fever is a viral infection that is spread by mosquitoes to people. The fever is most common in tropical and subtropical climates. Imma Perfetto, a Cosmos science journalist, states that, “Mild cases of dengue may be asymptomatic or cause fever and flu-like symptoms.  Severe cases can cause serious bleeding, a sudden drop in blood pressure (shock), and death.” Currently the fever is treated with pain medication, but the disease doesn’t have a cure.  

There are steps being taken to reduce the problem but climate change could make the job of health workers more challenging. According to David Cox, a writer for the British Broadcasting Corporation (BBC), cold blooded animals, such as mosquitos, can’t self-regulate their body temperature. This means that the temperature of their environment determines every aspect of their lives, such as their bite rate or how fast they mature. With global temperatures rising, particularly favourable conditions are created for dengue-carrying mosquitos.  

Early last year, Erin and colleagues, Marrisa Childs, Kelsey Lyberger, Mallory Harris, Marshall Burke, who are professors and researchers at Harvard University, Stanford University and the National Bureau of Economic research, assessed the impact of temperature of dengue in the Americas and Asia. They say, “We found that dengue incidence responds nonlinearly to temperature, increasing up to a peak at 27.8°C and declining at higher temperatures.” This means that South America could face big future risks, with cases of dengue rising by up to 200% in the upcoming decades. 

Preparing for the future, researchers hope that countries will do more tracking and reporting of dengue cases. “Since we’ve established this relationship between temperature and cases, the next step is to see how warming, both in the past and in the future, is going to affect the number of cases that we have or will see,” says Dr Kelsey Lyberger, an ecologist at Arizona State University.  With the information they gather, hopefully governments, scientists and researchers can work together to help reduce the amount of people at risk of dengue fever. 

Nora Vastag was an outstanding participant in Double Helix’s Young STEM Journalism Bootcamp. This year, Double Helix partnered with Letterly to launch the inaugural 4-week program, inviting students aged 8 to 18 to write science news articles on the topics that matter to them! This article went through multiple rounds of editing with 1-to-1 feedback from Letterly’s highly qualified and passionate writing coaches. Double Helix editors provided a final edit for accuracy and style.