A team led by Zhiyong Xi, a medical entomologist at Michigan State University in East Lansing, infected Anopheles stephensi mosquitoes with Wolbachia bacteria to produce insects that could pass the infection on to their offspring. Female mosquitoes that carried Wolbachia also bred with uninfected mates, the researchers report today in Science, swiftly spreading the malaria-blocking bacterium to entire insect populations within eight generations.

“This is the first paper reporting that it is indeed possible to use Wolbachia to control malaria,” says geneticist Steven Sinkins of the University of Oxford, UK. But he cautions that field trials will be the real test of this advance.

Wolbachia has already been used to block mosquitoes’ ability to transmit other human pathogens. For instance, scientists have created heritable infections in Aedes aegypti mosquitoes that stop the insects from transmitting dengue virus. But manipulating those mosquitoes that carry the malaria parasite exclusively — from the genus Anopheles — has proved trickier.