CRISPR can stop malaria spread by editing a single gene in mosquitos

CRISPR gene-editing therapy has shown great potential to treat and even cure diseases, but scientists are now discovering how it can be used to prevent them as well. A team of researchers found a way to edit a single gene in a mosquito that prevented it from transmitting malaria, according to a paper published in Nature. These genetically modified mosquitos could eventually be released into the wild, helping prevent some of the 600,000 malaria deaths that occur each year.

Mosquitos infect up to 263 million people yearly with malaria and efforts to reduce their populations have stalled as late. That’s because both the mosquitos and their parasites that spread malaria have developed resistance to insecticides and other drugs.

Now, biologists from UC San Diego, Johns Hopkins and UC Berkeley universities have figured out a way to stop malarial transmission by changing a single amino acid in mosquitos. The altered mosquitos can still bite people with malaria and pick up parasites from their blood, but those can no longer be spread to others.

The system uses CRISPR-Cas9 “scissors” to cut out an unwanted amino acid (allele) that transmits malaria and replace it with a benign version. The undesirable allele, called L224, helps parasites swim to a mosquito’s salivary glands where they can then infect a person. The new amino acid, Q224, blocks two separate parasites from making it to the salivary glands, preventing infection in people or animals.

“With a single, precise tweak, we’ve turned [a mosquito gene component] into a powerful shield that blocks multiple malaria parasite species and likely across diverse mosquito species and populations, paving the way for adaptable, real-world strategies to control this disease,” said researcher George Dimopoulos from Johns Hopkins University.

Unlike previous methods of malarial control, changing that key gene doesn’t affect the health or reproduction capabilities of mosquitos. That allowed the researchers to create a technique for mosquito offspring to inherit the Q224 allele and spread it through their populations to stop malarial parasite transmission in its tracks. “We’ve harnessed nature’s own genetic tools to turn mosquitoes into allies against malaria,” Dimopoulos said.

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