Medium range olfactory responses of the malaria vector Anopheles gambiae to synthetic odor blends

Abstract

The interaction between the malaria vector Anopheles gambiae and its human host is mediated mainly by olfactory cues that emanate from the host. Several compounds from whole body odor, sweat and breath are proven mosquito kairomones. Medium range olfactory responses of An. gambiae s.s to ammonia, carbon dioxide (C02) and selected carboxylic acids were evaluated using semi-field binary assays. Traps baited with a blend consisting of ammonia, CO2 and optimal concentrations of the carboxylic acids caught 17% [12%-23%] of all responding mosquitoes when tested in competition with human foot odors plus CO2. The binary assays were found to be advantageous for rapid evaluation of behaviorally active compounds. Evidently. ammonia, carbon dioxide and the candidate carboxylic acids are not the only compounds that mediate Anopheles olfactory responses to humans. However. it is concluded that by combining selected attractants at their optimal concentrations, it is possible to formulate a blend that is optimally attractive to host seeking mosquitoes. The odor blend developed in this study can be readily used to develop high impact interventions or sampling tools that target malaria mosquitoes.