Scientists deploy ‘mosquito STD' to fight malaria in bold biotech breakthrough

Yahoo

05-06-2025

Scientists have flipped the script on mosquitoes, turning their mating rituals into a lethal weakness.
In a striking twist on pest control, researchers have engineered a sexually transmitted fungus that strikes during sex, infecting and killing mosquitoes from within.
This microscopic assassin offers fresh hope in the fight against malaria, a disease that kills more than 600,000 people each year, most of them young children in sub-Saharan Africa.
The fungus targets female mosquitoes, the ones that bite and spread the disease, delivering a fatal blow at the moment they mate.
And unlike chemical sprays or bed nets, which mosquitoes have learned to dodge, this approach hijacks their most basic instinct—ensuring the fungus spreads naturally, one deadly encounter at a time.
'It's essentially an arms race between the mosquitoes and us,' said study co-author Raymond St. Leger, a university professor of Entomology at the University of Maryland, in a release.
'Just as they keep adapting to what we create, we have to continuously develop new and creative ways to fight them.'Mosquitoes' remarkable ability to adapt has long frustrated disease-control efforts. As indoor repellents like bed nets and insecticide sprays improved, mosquitoes shifted tactics, moving outdoors and striking at new times to avoid human defenses.
To counter these evasive pests, the team enhanced a naturally occurring fungus called Metarhizium, equipping it to produce insect-specific neurotoxins that kill once inside a female mosquito's body.
Instead of direct application, the fungus rides into action via infected male mosquitoes, which are dusted with fungal spores and released. When they mate, they pass the killer fungus directly to their partners.
In real-world field trials in Burkina Faso, nearly 90 percent of female mosquitoes that mated with fungus-laden males died within two weeks compared to just 4 percent in the control group.
Crucially, while deadly to mosquitoes, the modified Metarhizium poses no threat to humans.
'What makes this fungus particularly promising is that it works with existing mosquito behavior rather than against their natural habits,' St. Leger said.
'Unlike pesticides or other chemical control methods that mosquitoes can develop resistance to, this method uses the mosquitoes' own biology to deliver the control agent.'
Researchers also discovered that infected males could continue transmitting the fungus for up to 24 hours after initial exposure, enabling each male to infect multiple females over time.
'Interestingly, we noticed that the presence of the fungus did not deter female mosquitoes from mating with infected males. Mating rates stayed the same, which makes this fungus a very powerful mosquito population control tool,' St. Leger said. 'And the fungus additionally made infected mosquitoes less able to sense insecticides, and much more susceptible to them, so it's really a double blow against them.'
With Metarhizium already widely used in agriculture for pest control, scientists believe this mosquito-specific adaptation could be a game changer, especially when paired with existing methods.
While hurdles remain to scale up the 'mosquito STD' for widespread use, the study marks a major leap forward in the long battle against mosquito-borne diseases.
'Mosquitoes are the world's deadliest animal. It's believed that they alone, by transmitting disease, have killed half of all human beings who have ever lived,' St. Leger noted. 'Being able to eliminate mosquitoes quickly and effectively will save people all over the world.'
The study has been published in Scientific Reports.