West African mosquitoes infected with the bacterium Wolbachia are less likely than uninfected ones to carry the malaria parasite Plasmodium.
Wolbachia infection has long been proposed as a way to reduce the spread of mosquito-borne diseases such as malaria. To study natural Wolbachia infection, Flaminia Catteruccia at the Harvard T. H. Chan School of Public Health in Boston, Massachusetts, and her colleagues collected and studied 221 Anopheles coluzzii mosquitos from a village in Burkina Faso. They found that about half of the insects carried a Wolbachia strain. Only one infected mosquito (less than 1%) was also infected with Plasmodium, whereas roughly 10% of the 105 mosquitos free of Wolbachia tested positive for the malaria parasite.
Mathematical modelling suggested that even at this rate of Wolbachia infection, the bacterium could decrease the prevalence of malaria in humans.