“To try to get rid of them, I don’t think it’s possible,” he says. Instead, James and his colleagues want to try a different approach: making mosquitoes themselves into malaria-fighting warriors.
To understand how it works, it helps to understand the life cycle of malaria. The malaria pathogen is a parasite that grows inside humans. It’s transmitted via mosquitoes that flit from person to person, sucking blood (the parasites also reproduce inside the guts of skeeters).
“If we can make the mosquitoes inhospitable to the pathogens, you know, we can eliminate the threat of getting the disease,” he says.
But making mosquitoes uninviting to malaria is a tough job. The malaria parasite doesn’t make mosquitoes sick, so mosquito immune systems don’t fight it.
To get around the problem, the team used a gene-editing technique called CRISPR. They started with genes from mice, whose immune systems do fight human malaria.
“What we did then was engineer those [genes], and give them to the mosquitos,” he says.
The results were published this month in the Proceedings of the National Academy of Sciences. Sure enough, the gene-edited mosquitos produced malaria-fighting antibodies.
Those antibodies “worked very well,” says James. “They reduce the number of parasites in the mosquito, most importantly in the salivary gland, which is where they would be before they were transmitted to a human host.”
This technique also allows the researchers to make the genes spread quickly. That means, rather than having to release swarms of gene-edited mosquitos, they could put out a smaller number. The engineered mosquitoes mate, pass on their genetic code, and that code rapidly fans out across the wild population.