All mosquitoes are not created equal. Different species of the flying pest thrive at various temperature ranges and transmit different diseases. From this starting point, a Stanford-led paper for the first time predicts how, when and where in Sub-Saharan Africa malaria will ebb and other mosquito-borne diseases, such as dengue fever, will rise dramatically. The article, published Sept. 9 in Lancet Planetary Health, warns of a public health disaster if the region fails to supplement its focus on malaria to include strategies tailored to other mosquito-borne diseases.

Graphic showing possible scenarios of temperature-driven changes in disease risk across Sub-Saharan Africa under a “business as usual” climate scenario. Red circles denote disease risk hotspots. Color scale indicates the intensity of human exposure risk, based on temperature.
Image/Mordecai, et al. / Lancet Planetary Health


“Climate change is going to rearrange the landscape of infectious disease,” said Stanford biologist and study lead author Erin Mordecai. “Chikungunya and dengue outbreaks like we’ve recently seen in East Africa are only becoming more likely across much of the continent. We need to be ready for this emerging threat.”

A tale of two mosquitoes

The nighttime-biting Anopheles gambiae mosquito transmits malaria, a disease that affects more than 200 million people in Sub-Saharan Africa, and killed more than 400,000 people there in 2018. For years, public health efforts in the region have taken aim at the scourge with insecticide-treated bed nets and indoor spraying, among other measures.

18 infections you can get from mosquitoes

These malaria-focused control strategies, however, do little to combat the daytime-biting Aedes aegypti mosquito, which can transmit a range of devastating diseases, such as Rift Valley Fever, yellow fever, Zika, chikungunya and dengue. Growing urbanization has expanded Aedes aegypti’s range by enlarging its preferred breeding grounds – human-made containers, such as discarded tires, cans, buckets and water storage jugs. In contrast, malaria-transmitting mosquitoes breed in naturally occurring pools of water more common in rural areas. Expanding urban areas also form heat islands or microclimates several degrees warmer than surrounding vegetated areas – another draw for the warm weather-loving Aedes aegypti.

Read more at Stanford University