A smarter way to control mosquitoes
A new method for separating nonbiting males from biting females that carry disease could make mosquito control faster, cheaper, and easier to scale.
image: Researcher Melanie Hempel handles a mosquito specimen in the lab. Hempel helped develop the DeMark system, a new method for producing nonbiting male mosquitoes for disease control.
Credit: Photo by Marya Barlow for Virginia Tech.
Scientists at Virginia Tech may have just made it easier to fight the world’s deadliest animal: the mosquito.
Only female mosquitoes bite because they need nutrients from blood to develop eggs. That drive makes them dangerous, allowing them to spread viruses such as Zika, dengue, malaria, and yellow fever, which together kill over 1 million people a year.
One promising disease control method is releasing sterile males, raised in labs, into the wild. When females mate with these sterile males, they don’t produce offspring, gradually shrinking the population without relying on insecticides that harm beneficial insects.
But this approach is technically complex, labor-intensive, and costly — limiting its effectiveness and scalability.
Now, researchers have taken a major step toward solving that problem. In a study published in Proceedings of the National Academy of Sciences, the team unveiled “DeMark” — a genetic system that streamlines the separation process. The method eliminates the need for manual sorting, multiple breeding lines, or foreign genetic material, making it easier to produce large batches of nonbiting male mosquitoes.
“This adds a potentially powerful new tool to global mosquito control efforts,” said Austin Compton, one of the study’s lead authors. “It’s relatively simple and scalable.”
The research was led by scientists from the Department of Biochemistry in the College of Agriculture and Life Sciences and the Fralin Life Sciences Institute.
About the DeMark system
DeMark — short for Differential Elimination of Marked sex chromosomes — uses genetic markers to separate out unwanted mosquitoes before they reach adulthood. What remains is a batch of nonbiting males that are not modified with any foreign genetic material.
To build the system, the researchers combined natural and lab-engineered versions of mosquito genes, or alleles, that are passed down through sex chromosomes. When inherited in certain combinations, these alleles cause some mosquitoes to die early. This built-in safeguard helps ensure that unmodified males are produced every generation and can be easily isolated based on their lack of marked sex chromosomes.
Unlike other approaches that require maintaining multiple breeding lines, DeMark works with a single breeding line, reducing both production costs and complexity.
The team also tested whether the lab-raised males could compete with wild-type mosquitoes when it came to mating. They did — a key factor for any control strategy to succeed outside the lab.
“Before these strains can be considered for potential field release, more work is needed to test their stability and competitiveness under mass-rearing and controlled semi-field conditions,” said Melanie Hempel, who co-led the research as a Ph.D. student and is now a postdoctoral researcher at Virginia Tech.
Adding to the mosquito control toolbox
This study focused on Aedes aegypti, the mosquito species known for spreading Zika, dengue, chikungunya, and yellow fever. The researchers say the same approach could potentially be adapted to other species, including Anopheles gambiae, which transmits malaria.
“This approach can work hand in hand with other mosquito control strategies,” said Zhijian “Jake” Tu, University Distinguished Professor and senior author of the study. “Our goal is to add to the growing toolbox of options available to fight mosquito-borne diseases in ways that make sense for different regions and communities around the world.”
The research was supported by the National Institutes of Health, the Virginia Agricultural Experiment Station, and other partners. Austin Compton was supported in part by a fellowship from the Robert Wood Johnson Foundation.
Other authors include Atashi Sharma, Azadeh Aryan, James K. Biedler, Mark B. Potters, and Clément Vinauger, all affiliated with the Department of Biochemistry and the Fralin Life Sciences Institute at Virginia Tech. Karthikeyan Chandrasegaran is affiliated with the Department of Entomology at the University of California, Riverside.
Original study: DOI 10.1073/pnas.2412149122