Genetic tweak in mosquitoes blocks malaria transmission without affecting insect health

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Genetic tweak in mosquitoes blocks malaria transmission without affecting insect health

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University of California - San Diego,  Phys.org,  2025.

Mosquitoes kill more people each year than any other animal. In 2023, the blood-sucking insects infected a reported 263 million people with malaria, leading to nearly 600,000 deaths, 80% of which were children. Recent efforts to block the transmission of malaria have been stalled because mosquitoes have adapted resistance to insecticides and the  within mosquitoes that cause malaria have become resistant to drugs. These setbacks have been amplified by the COVID-19 pandemic, which impeded ongoing anti-malarial efforts. Now, researchers at the University of California San Diego, Johns Hopkins University, UC Berkeley and the University of São Paulo have developed a new method that genetically blocks mosquitoes from transmitting malaria. Their work appears in Nature.

Biologists Zhiqian Li and Ethan Bier from UC San Diego, along with Yuemei Dong and George Dimopoulos from Johns Hopkins University, created a CRISPR-based gene-editing system that changes a single molecule within mosquitoes, a minuscule but effective change that stops the malaria-parasite transmission process. Genetically altered mosquitoes are still able to bite those with malaria and acquire parasites from their blood, but the parasites can no longer be spread to other people. The new system is designed to genetically spread the malaria resistance trait until entire populations of the insects no longer transfer the disease-causing parasites. “Replacing a  in mosquitoes with another naturally occurring variant that prevents them from being infected with malarial parasites—and spreading that beneficial trait throughout a mosquito population—is a game-changer,” said Bier, a professor in the UC San Diego Department of Cell and Developmental Biology (School of Biological Sciences). “It’s hard to believe that this one tiny change has such a dramatic effect.”