This project will characterize the olfactory mechanisms that determine how Anopheles stephensi specifically targets humans for blood feeding versus other animals. If successful, we will create a genetically modified A. stephensi strain that will avoid feeding on humans. Release of this mosquito coupled with a gene-drive mechanism could lead to replacement of current, human-seeking, populations. This could effectively break the disease transmission cycle, leading to reduction or eradication of malaria. Eradicating malaria would be a revolutionary development as it is currently responsible for over 250 million cases of illness annually, resulting in over 400,000 deaths.
Long lasting insecticide-treated bed nets in conjunction with indoor residual spraying have reduced malaria transmission by targeting mosquitoes with habits highly tied to feeding on sleeping humans within dwellings (notably Anopheles gambiae - Sub-Saharan Africa and Anopheles stephensi – Southern Asia). Mosquito repellents, habitat modification (to reduce larval development sites), and anti-malarial drugs also contribute to reductions in malaria cases.
Despite these efforts, malaria remains a problem for U.S. service members and civilians due to insecticide resistance, Plasmodium resistance to anti-malarial drugs, and mosquito behavioral changes (aversion to insecticide-treated surfaces, and outdoor feeding preferences), among other factors. Alternative approaches are therefore needed for improved control or eradication of this disease.
The most dangerous mosquito vector species are those that specialize in feeding on humans, facilitating rapid human-mosquito-human transmission of disease. This preference for humans is driven by the mosquito’s sense of smell, allowing it to discriminate human odors from those of other animals.