May 13, 2009

Study: Bacteria might stop malaria spread

U.S. scientists say they've found bacteria in the Anopheles gambiae mosquito that can stop the mosquito from being infected with the malaria parasite.

Johns Hopkins University researchers in the school's Bloomberg School of Public Health said the bacteria in the gut of the mosquito inhibit infection of the insect with Plasmodium falciparum, the parasite that causes malaria in humans.

The scientists said they determined removing the bacteria with antibiotics made the mosquitoes more susceptible to Plasmodium infection because of a lack of immune stimulation.

Our study suggests that the microbial flora of mosquitoes is stimulating immune activity that protects the mosquito from Plasmodium infection, said Associate Professor George Dimopoulos, lead author of the study. "The interplay between bacteria and the mosquito's immune system may have significant implications for the transmission of malaria in the field where mosquitoes may be exposed to different types of bacteria in different regions.

Theoretically, he added, these bacteria could be introduced to the mosquitoes to boost their immunity to the malaria parasite and make them resistant and incapable of spreading the disease. Our current research aims at identifying those bacteria that trigger the strongest mosquito immune defense against the malaria parasite.

The study appears in the journal PLoS Pathogens.