Urbanization, transportation, and climate change are rapidly expanding mosquito habitats. That’s bad news.
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Around 700,000 people die every year from mosquito-borne disease. The biggest culprit is malaria, but other mosquito-borne diseases, like dengue fever, chikungunya, and Zika, have proliferated wildly in recent years, and now make up a substantial share of the global burden of mosquito-borne disease. By some estimates, the number of dengue infections has increased 30-fold in the past 30 years.
The culprit? Climate change, plus urbanization and changes in where human populations are concentrated. And a new study in Nature Microbiology suggests that things will only get worse. Using statistical mapping techniques, they model how two disease-carrying mosquitos, Aedes aegypti and Aedes albopictus, have spread over the last 30 years, and predict how they’ll spread over the next 30.
The results are alarming. These species of mosquito — which carry infectious diseases including Zika, dengue, chikungunya, and yellow fever, though not malaria — are expected to spread throughout most of the United States and Europe, exposing hundreds of millions of people to these diseases.
“Overall,” the study finds, “our predicted expansions will see Ae. aegypti invading an estimated 19.96 million km by 2050 (19.91–23.45 million depending on the climate and urbanization scenarios), placing an estimated 49.13% (48.23–58.10%) of the world’s population at risk of arbovirus transmission.”
The expanding range of disease-transmitting mosquitos is a significant source of harms from climate change. These diseases largely have low mortality, but serious quality-of-life costs (in the case of Zika, brain damage in fetuses). It’s not clear that most countries are ready to address the public health challenge.