In 2025, Harvard University developed a chemical coating for insecticide-treated bed nets that blocks malaria parasites inside mosquitoes instead of killing the insects. It produced a breakthrough that could fight malaria without increasing insecticide resistance

A new approach to malaria control could change how insecticide-treated bed nets are used. In 2025, a Harvard-led research team identified chemical compounds that can kill malaria parasites inside mosquitoes after the insects come into contact with treated netting.

The strategy is designed to target the parasite rather than the mosquito, potentially offering a way to tackle malaria transmission without adding to the growing problem of insecticide resistance.

The collaborative research, published in Nature, involved scientists at Harvard T.H. Chan School of Public Health, Oregon Health & Science University (OHSU), the Portland Veterans Affairs Medical Center and Southwest Research Institute (SwRI).

How does the new malaria strategy work?

The research focused on endochin-like quinolones, known as ELQs, a class of experimental antimalarial drugs. Researchers at Harvard screened 81 chemical compounds for their ability to interfere with the mosquito stages of Plasmodium falciparum, the parasite responsible for malaria.

The screening identified 22 compounds that were active against early parasite stages inside the mosquito's digestive tract. Further medicinal chemistry work produced several ELQs with stronger antiparasitic activity.

Two compounds emerged as the strongest candidates. When incorporated into or applied to net-like polyethylene materials, they killed 100% of the parasites at very low concentrations and remained active for more than a year.

The idea is simple: an infected mosquito lands on the treated net, absorbs the compound through its legs and the drug attacks the malaria parasites it carries.

“If an infected mosquito hits or lands on netting containing either of the ELQs, it’s essentially disinfected. It absorbs the treatment via its legs, and that kills the parasites that it’s carrying,” said Mike Rubal, Ph.D., a scientist at Southwest Research Institute who contributed to the Nature study. “The best defense against malaria has been insecticide-treated bed nets, but mosquitoes are developing a resistance to those prevention methods. This novel approach targets the source of the disease," said Mike.

Why target parasites instead of mosquitoes?

Malaria control has relied heavily on insecticide-treated bed nets, but increasing insecticide resistance among Anopheles mosquitoes has become a major obstacle.

The researchers said targeting parasites during their mosquito stage could help bypass that problem because the approach does not depend on killing the insect.

“Insecticide resistance is now extremely common in the mosquitoes that transmit malaria, which jeopardizes many of our most effective control tools,” said Alexandra Probst, M.Pharm, lead author of the study and a Ph.D. candidate in Flaminia Catteruccia's Harvard laboratory. “By targeting malaria-causing parasites directly in the mosquito, rather than the mosquito itself, we can circumvent this challenge and continue to reduce the spread of malaria.”

The research therefore explores a different way of interrupting malaria transmission, even when mosquitoes have become resistant to conventional insecticides, as per "In vivo screen of Plasmodium targets for mosquito-based malaria control", a research article published in the journal Nature.

Who developed the experimental bed-net treatment?

The work was led by researchers associated with Harvard T.H. Chan School of Public Health, with important contributions from OHSU, PVAMC and SwRI.

Michael Riscoe, Ph.D., professor of molecular microbiology and immunology at OHSU, designed and synthesized the ELQ compounds. Flaminia Catteruccia, Ph.D., the study's senior author and Irene Heinz Given Professor of Immunology and Infectious Diseases at Harvard, led the mosquito research and screening.

SwRI used its drug formulation and manufacturing expertise to create two bed-net prototypes. One involved coating commercially available polyester netting with an ELQ solution, while another formulation was incorporated into high-density polyethylene filaments that could be woven into netting.

“We desperately need innovation in malaria control. This study offers a new, effective way to stop the transmission of malaria parasites, which we hope will reduce the burden of this devastating disease in Africa and beyond,” said Catteruccia.

Could the treatment help fight malaria?

The need for new malaria-control tools remains significant. In 2023, the World Health Organization reported 263 million malaria cases and nearly 600,000 deaths worldwide.

The ELQ-treated materials showed activity even against mosquitoes resistant to traditional insecticides. Researchers also found that using two different ELQs could further reduce the likelihood of resistance developing against the treatment.

“Our research shows that the two drugs, which are absorbed through the legs of the insect, kill parasites developing within the mosquito. By using two different ELQs, the likelihood of resistance is greatly diminished and possibly eliminated,” said Riscoe.

The researchers said further work is needed to determine whether ELQs should be incorporated alongside insecticides in bed-net fibers or eventually used on their own.

The next step is field testing of ELQ-impregnated bed nets. That work is expected to test whether the promising laboratory results can translate into a practical tool for malaria control.

“This work has potential to significantly blunt the transmission of malaria,” Riscoe said. “I think that it will evolve and develop to be a key element to our success in eradicating malaria around the world," as per "In vivo screen of Plasmodium targets for mosquito-based malaria control", a research article published in the journal Nature.

FAQs

What do the new bed nets target?
They target malaria parasites inside mosquitoes.

Why is this approach important?
It could bypass insecticide resistance.