Harvard University researchers have found evidence of a bacterial infection that occurs naturally in the same species of mosquitos that cause malaria, according to a new study. The infection, Wolbachia, has been shown in laboratories to reduce the incidence of malaria in infected mosquitoes, of the species known as Anopheles.
The research is important because it could pave the way for controlling mosquito populations in areas of the world affected by malaria. According to the World Health Organization, there were 207 million cases of malaria worldwide in 2012, with 627,000 deaths, primarily in countries in Africa, Asia, and South America.
“Wolbachia is an interesting bacterium that seems perfectly suited for mosquito control. However, there were strong doubts that it could ever be used against field Anopheles populations,” says Flaminia Catteruccia, associatee professor of immunology and infections diseases at Harvard School of Public Health and at the University of Perugia, Italy. “We were thrilled when we identified infections in natural mosquito populations, as we knew this finding could generate novel opportunities for stopping the spread of malaria.”
Anopheles mosquitoes are the deadliest animal on the planet, according to information provided by Harvard. These mosquitoes are responsible for transmitting malaria. Wolbachia infections spread rapidly through wild insect populations by inducing a reproductive phenomenon called cytoplasm incompatibility (CI). Inducing CI in the mosquitoes could reduce the numbers of Anopheles mosquitoes in areas with high rates of malaria, thereby reducing infections in people. Sixty-six percent of arthropod species are infected with Wolbachia.
Study co-author Francesco Baldini, from University of Perugia, Italy and Harvard, and other researchers, collected Anopheles mosquitoes from villages in Burkina Faso, West Africa, and analyzed their reproductive tracts. Their objective was to identify all the bacteria in the reproductive systems of both male and female mosquitoes. However, they were not looking directly for Wolbachia. To their surprise, they found a novel strain of the infection, which they named wAnga.
The researchers say they can now investigate whether the wAnga strain shares properties with other Wolbachia strains. This could make control strategies possible by inducing CI and reducing Plasmodium (the parasite that causes malaria) numbers in Anopheles mosquitoes in the field.
“If successful, exploiting Wolbachia infections in malaria mosquitoes could reduce the burden of the disease globally,” says co-author Elena Levashina, from the Max Planck Institute for Infection Biology, Berlin.