New Gene Drive Stops the Spread of Malaria—Without Killing Any Mosquitoes

Mosquitoes are an uncomfortable, itchy nuisance. But for people in sub-Saharan Africa, a bite could mean death. The pests are living incubators for the parasite that causes malaria. Roughly 600,000 people are killed by the disease each year, with most being children under five years of age.

Insecticides, malaria drugs, and mosquito nets saved a million lives globally in 2024 alone. But their efficacy is waning. Mosquitoes and the malaria parasite are becoming resistant to chemical inhibitors. And consistent, perfect use of physical barriers is hard to manage for years on end, especially for children.

Realizing this, scientists have turned to a drastic solution: Gene drives, a technology that skews the rules of inheritance. Rather than nature’s fifty-fifty chance of an offspring inheriting a gene from either parent, gene drives raise the possibility of a gene’s inheritance to over 90 percent—if not higher.

The tweak allows a gene to rapidly spread across entire populations. In lab tests encoding gene drives that reduce female mosquito fertility, mosquito populations have collapsed. Other experimental gene drives encoding genes that block parasite reproduction have suggested they could replace a natural population with one unable to carry malaria in just a few generations.

But these studies mostly used a specific type of lab-grown mosquito and older generations of the malaria parasite. Whether gene drives could keep naturally circulating malaria parasites in check, especially in countries where they’re most prevalent, was unknown.

This month, a research team from Tanzania and the UK found engineered mosquitoes conquered a wide variety of malaria parasites in blood samples collected from children in the area. Genetically altered in a new state-of-the-art biosecurity facility in Tanzania, the mosquitoes passed on genes that inhibit the parasite with breakneck speed and efficiency.

The promising findings are the latest from Transmission Zero, a Tanzania-led and internationally supported project to develop genetically based mosquito suppression.

“Gene-drive mosquitoes…offer unprecedented hope,” wrote study authors Alphaxard Manjurano at the National Institute for Medical Research Mwanza Center and Dickson Lwetoijera at the Ifakara Health Institute, both based in Tanzania.

Moving South

Gene drives shatter the laws of evolution. Rather than a fifty-percent chance of inheriting genes from a parent, gene drives pass genes down through generations with near-certainty.

Scientists engineer gene drives by first adding instructions to make the gene editing tool CRISPR. These instructions are genetically inserted into a single chromosome in a chromosome pair. The chromosomes in these pairs are inherited one from each parent. The drive hijacks the bug’s protein-making machinery to pump out Cas9 “scissors” that break the sister chromosome.

Rather than stitching the broken ends together, the cells use the gene-drive containing chromosome as a template for repair. And now both chromosomes contain the drive, ensuring it’ll be passed down to future generations.

Gene drive design is extremely versatile. Some drives target genes involved in female fertility, making mosquitoes sterile and quickly lowering their numbers. Others produce malaria antibodies in female mosquitoes when they drink blood, neutralizing the parasite and preventing it from spreading. Yet others propagate a protective gene that naturally wards off malaria in mosquitoes.

The latter strategies are gaining steam. Not everyone is keen on eliminating entire species. Mosquitoes may play diverse roles in ecosystems that we haven’t yet discovered. Kneecapping malaria parasites as they grow in mosquitoes seems like the safer bet.

But previous gene-drive mosquitoes were designed and tested using old, frozen malaria samples—a far cry from the genetic diversity and rapid evolution that make the parasite formidable in natural environments. Bringing the technology to regions heavily affected by the disease could help local communities better battle the disease.

Hidden Medicine

The new gene drive relied on previous efforts from George Christophides at Imperial College London who was also an author of the new study. Malaria parasites take roughly 10 days to incubate and develop inside mosquitoes. Once mature, they spread into the bug’s saliva, which can now infect people. Because the mosquito carriers don’t survive long past this period—but can do lots of damage in the meantime—delaying parasite development could crash the entire transmission cycle.

The team took inspiration from two small proteins that naturally cripple parasite development. One was discovered in the African clawed frog; the other in honeybees. Parasites in lab-grown mosquitoes, engineered to contain gene drives loaded with the proteins, took a few days longer to mature—precious time during which some of the bugs naturally died off.

Collaborators in Tanzania recreated these gene drive mosquitoes and tested them in a near real-world setting. After feeding on blood samples from local children infected by various strains of the parasite, the edited mosquitoes struggled to produce more of the pathogen.

“This is the first time a genetically modified, gene drive-compatible mosquito strain has been developed in Africa, by African scientists, targeting malaria parasites circulating in local communities,” said Lwetoijera in a press release. However, long-term monitoring is essential to make sure the parasite doesn’t develop resistance against the gene drive. The treatment presents a new way to slash malaria risks in plagued communities.

The project didn’t just rely on scientific insights. In a country with relatively low resources, little infrastructure, and hazy regulations, building the research program from the ground up was a top priority to ensure biocontainment safety. The study was conducted in a state-of-the-art facility specifically designed for this research, allowing local scientists to spearhead future genetic engineering efforts and field testing.

A daring trial to release the edited mosquitoes on an island in Lake Victoria is planned for the next phase. Throughout the project, Transmission Zero has worked with local communities to build trust in a bewildering technology. Plenty of protocols and planning need to be in place before a real-world test takes place. These include ecological risk assessment, regulatory oversight, and continued development of skills and expertise in staff leading the effort.

Both Manjurano and Lwetoijera stressed the importance of African leadership as the project moves along, ensuring that as the technology is developed and implemented it meets local priorities and ethical standards.

International collaborators agree. “Now, we want to move at the right speed. It is important that we’re not too fast and that we make sure people are supportive of this new technology, but we should also move with urgency and treat malaria as the emergency that it is,” said study author Nikolai Windbichler at Transmission Zero and Imperial College London.