By the time the sun sets in Burkina Faso, swarms of mosquitoes rise with it—tiny, buzzing engines of one of the world’s oldest and deadliest diseases. But now researchers have turned one of the insects’ greatest strength—their sheer reproductive drive—into their downfall.

In a new study, scientists revealed a new kind of biocontrol agent that sounds more like science fiction than public health strategy: a sexually transmitted fungal infection designed to kill mosquitoes. Once transferred from male to female during mating, the genetically modified fungus—harmless to humans—kills almost 90 percent of female mosquitoes within two weeks. These are the very mosquitoes responsible for transmitting malaria, a disease that claims more than 600,000 lives each year, most of them young children in sub-Saharan Africa.

Sex, Spores, and Survival

The innovation centers on a fungus called Metarhizium pingshaense, long known for its ability to kill insects. But scientists at the University of Maryland and institutions in Burkina Faso reengineered it to produce a hybrid neurotoxin—lethal to mosquitoes but inert to other species. The fungus is weaponized through sex.

In controlled tests, researchers dusted male mosquitoes with spores of the modified fungus and released them into semi-field compartments—enclosures designed to mimic natural conditions. The males mated as usual, and in the process, transmitted fungal spores to their partners.

The outcome was dramatic: nearly 9 out of 10 females died within 14 days, compared to only 4% in the control group.

That’s not all. The infection didn’t deter the insects from mating. “Interestingly, we noticed that the presence of the fungus did not deter female mosquitoes from mating with infected males,” said Raymond St. Leger, a Distinguished University Professor of Entomology at the University of Maryland and co-author of the study. “Mating rates stayed the same, which makes this fungus a very powerful mosquito population control tool.”

Even more remarkable, the infected males remained contagious for up to 24 hours—meaning they could infect multiple females in that period. Unlike insecticides that often face resistance, the fungus-based approach cleverly exploits mosquito biology.

From Lab to Field—and Beyond

The research, conducted by a team from the Institut de Recherche en Sciences de la Santé in Bobo-Dioulasso, Burkina Faso, along with U.S. collaborators, was designed with real-world applications in mind. The team tested both wild-type and transgenic versions of the fungus. Only the genetically modified version showed the kind of rapid mortality that could meaningfully suppress mosquito populations.

“The transgenic fungus was more effective at killing mosquitoes than the wild-type fungus,” the authors wrote in the study. Females did not die from merely sharing space with infected males—it had to be sexual contact.

This discovery is particularly important because of how mosquitoes have evolved. In response to insecticides and indoor interventions like bed nets, many malaria-transmitting species have shifted to outdoor feeding and resting. That makes them harder to target with conventional tools.

By introducing fungal infections via mating, scientists can sidestep that behavioral change entirely.

And there’s another twist: the fungus also appears to make mosquitoes more vulnerable to insecticides. According to St. Leger, the hybrid toxin disrupts the insects’ ability to sense chemicals. “It’s really a double blow against them,” he said.

While early data is promising, researchers caution that the method still requires further refinement before large-scale deployment. For one, releasing infected males into the environment raises logistical and ethical questions. Preliminary modeling also suggests that the timing of male release and the positioning of swarms in relation to natural features like sunset direction can influence success rates.

Still, the potential applications are tantalizing, especially when combined with other techniques like the Sterile Insect Technique (SIT) or the use of Wolbachia bacteria to block disease transmission.

A Deadly Legacy

Malaria remains one of the oldest scourges in human history. Some scientists estimate that mosquitoes, through the diseases they spread, have killed half of all humans who have ever lived. Today, despite decades of effort, malaria remains stubbornly persistent, especially in parts of West and Central Africa.

Progress has slowed in recent years. Mosquitoes have become increasingly resistant to insecticides, and parasites have begun to develop tolerance to drugs like artemisinin. The World Health Organization has called for new tools and strategies.

This sexually transmitted fungus is exactly the kind of out-of-the-box innovation that could answer that call.

“It’s essentially an arms race between the mosquitoes and us,” said St. Leger. “Just as they keep adapting to what we create, we have to continuously develop new and creative ways to fight them.”

For now, the war against malaria continues. But thanks to a microscopic fungus—and the very act of mosquito reproduction itself—the battlefield may finally be shifting in humanity’s favor.

The findings appeared in the journal Scientific Reports.