To keep mosquitoes from transmitting malaria, aim for the gut. Two research teams have found that tinkering with mosquitoes’ resident microbes can help them spread resistance to the malaria parasite. One used “weaponized” bacteria to deliver parasite-stopping proteins to mosquito guts. The other found that mosquitoes with a malaria-blocking gene have an unexpected mating advantage thanks to their microbes.
“I found both of [the studies] exciting in different ways,” molecular biologist Omar Akbari of the University of California, Riverside, says. “I really hope to see these technologies tested in the field.”
After biting a person infected with malaria, a female Anopheles mosquito harbors the malaria parasite—Plasmodium falciparum—in its gut. So molecular entomologist Marcelo Jacobs-Lorena of Johns Hopkins University in Baltimore, Maryland, and colleagues have developed strains of genetically modified bacteria that fight the parasite and lower the chance that an insect will pass it on with its next bite. But so far, it’s been hard to get these helpful bacteria to spread through a mosquito population.
Recently, a routine dissection turned serendipitous. Sibao Wang, a postdoc in Jacobs-Lorena’s lab who has since moved to Chinese Academy of Sciences in Shanghai, found fluid in a mosquito ovary that seemed cloudy to him—a possible indicator that it harbored bacteria. The bacterial variety he discovered, a new strain in the common genus Serratia, loved to spread. When female Anopheles gambiae mosquitoes ate sugar laced with the Serratia, it quickly populated their guts. The bacterium appeared on the surface of their…