Experimental bed nets target malaria parasite inside mosquitoes

Scientists at Harvard T.H. Chan School of Public Health, led by HHMI Investigator Flaminia Catteruccia, have created a new class of bed nets that attack the malaria parasite directly inside the mosquito rather than killing the insect. The approach aims to circumvent the growing problem of mosquito resistance to traditional insecticides used on standard bed nets.

The research team identified that the parasite's mitochondria fuel its rapid multiplication inside the mosquito over a two-week period. They first tested atovaquone, an existing antimalarial drug known to block mitochondrial function, and found that mosquitoes resting on atovaquone-coated surfaces became parasite-free after feeding on infected blood.

Because atovaquone was not optimized for bed-net absorption, the lab collaborated with Oregon Health & Science University to develop two new compounds, endochin-like quinolones (ELQs), that penetrate the mosquito's cuticle and hit two separate targets on an essential mitochondrial protein. This dual action makes it significantly harder for the parasite to develop resistance.

Working with the Southwest Research Institute, the team devised a method to coat full-scale bed nets with the ELQ compounds. In field tests conducted in Adama, Ethiopia, mosquitoes exposed to the treated nets and then fed blood drawn from local malaria patients showed no parasite development, confirming effectiveness against genetically diverse, circulating strains.

Larger-scale experiments are scheduled for Ethiopia's peak malaria season in September and October. Volunteers will sleep in experimental huts under the treated nets to evaluate protection under realistic exposure conditions. If successful, large-scale epidemiological trials comparing the new nets with current standard nets would follow.

The researchers are also investigating additional parasite vulnerabilities, such as the PfApiAT2 amino-acid transporter, to expand the number of simultaneous attack points. Catteruccia emphasized that targeting multiple independent pathways reduces the likelihood of resistance emerging.