US scientists have found a way to infect mosquitoes with bacteria in order to break the chain of malaria transmission, according to research published Thursday in a leading scientific journal.
A similar approach has helped cut back on dengue in some locations, and researchers hope that the findings could offer a path toward reducing malaria among the most common mosquitoes in the Middle East and South Asia.
The bacterial infection is inheritable and could be passed on for as many as 34 generations of mosquitoes, rendering them immune to malaria parasites, reported experts from the National Institutes of Health in the journal Science.
Scientists injected Anopheles mosquito embryos with Wolbachia, a common insect bacterium. When the mosquitoes matured, they bred the adult females with uninfected males.
The infection endured for 34 generations of mosquitoes. The study ended at that point, so it remains unknown how much longer the bacterial infection would have been passed on, preventing malaria transmission.
Researchers also tried introducing the bacterial infection in small numbers of adult mosquitoes, between five and 20 per cent of females in a given population.
Within eight generations, all of the mosquitoes were infected with the malaria-blocking infection.
The evidence supports the "potential of Wolbachia-infected mosquitoes as a malaria control strategy," said the study.
Previous research has shown the bacterium could prevent malaria-inducing Plasmodium parasites from developing in Anopheles mosquitoes.
But in this study, scientists were able to show for the first time that they could create mosquitoes with a stable Wolbachia infection that passed consistently from mother to offspring.
Researchers also discovered that the infection killed malaria parasites both in the mosquitoes' guts and in the salivary glands, the main avenue for transmission to humans via mosquito bites.
About 660,000 people die worldwide every year from malaria.