Researchers expect some mosquito-borne diseases to rise
Measures are likely to lower the rate of some diseases, but may increase others
17th September 2020
Not all mosquitoes are created equal.
Different types of the flying pest thrive in different temperature ranges and transmit different diseases. From this starting point, Stanford-led research predicts for the first time how, when and where malaria will subside – and that other mosquito-borne diseases like dengue will increase dramatically in sub-Saharan Africa.
The US National Science Foundation-funded study, published in Lancet Planetary Health, warns of a public health disaster if the region does not expand its focus on malaria to other mosquito-borne diseases.
“Climate change will rearrange the infectious disease landscape,” said Stanford biologist and study director Erin Mordecai. “Chikungunya and dengue outbreaks, as we saw recently in East Africa, are becoming more likely in much of the continent. We need to be prepared for this emerging threat.”
The nocturnal Anopheles gambiae mosquito transmits malaria, a disease that affects more than 200 million people in sub-Saharan Africa and which killed more than 400,000 people there in 2018. For years, public health efforts in the area have targeted the scourge Insecticide treated bed nets and indoor spraying, among others.
However, these malaria-focused control strategies do little to control the daytime mosquito, Aedes aegypti, which can transmit devastating diseases such as rift valley fever, yellow fever, zika, chikungunya and dengue fever.
Increasing urbanization has expanded the Aedes aegypti range by expanding its favorite breeding grounds – man-made containers such as discarded tires, cans, buckets and water storage jugs. In contrast, malaria-carrying mosquitoes breed in naturally occurring pools of water, which are more common in rural areas.
As in America, new public health efforts in sub-Saharan Africa to combat Aedes aegypti and dengue, chikungunya and other viruses need to be added to existing malaria control measures, the researchers argue. The development of a precise point-of-care diagnosis for dengue and chikungunya viruses as well as community-based mosquito control such as removing rubbish and covering stagnant water is becoming increasingly important.
“The world is changing in many complex ways,” said Sam Scheiner, program director in NSF’s environmental biology division. “This research is what we need to prepare for these changes.”
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