Development and field evaluation of a synthetic mosquito lure that is more attractive than humans
Biomedical and Environmental Sciences Thematic Group, Ifakara Health Institute, Ifakara, Tanzania; School of Biological Sciences, University of Nairobi, Nairobi, Kenya; Disease Control and Vector Biology Unit, London School of Hygiene and Tropical Medicine, London, United Kingdom; School of Biological Sciences, Durham University, Durham, United Kingdom; Vector Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom; College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, United States; Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, Netherlands
Background: Disease transmitting mosquitoes locate humans and other blood hosts by identifying their characteristic odor profiles. Using their olfactory organs, the mosquitoes detect compounds present in human breath, sweat and skins, and use these as cues to locate and obtain blood from the humans. These odor compounds can be synthesized in vitro, then formulated to mimic humans. While some synthetic mosquito lures already exist, evidence supporting their utility is limited to laboratory settings, where long-range stimuli cannot be investigated. Methodology and Principal Findings: Here we report the development and field evaluation of an odor blend consisting of known mosquito attractants namely carbon dioxide, ammonia and carboxylic acids, which was optimized at distances comparable with attractive ranges of humans to mosquitoes. Binary choice assays were conducted inside a large-cage semi-field enclosure using attractant-baited traps placed 20 m apart. This enabled high-throughput optimization of concentrations at which the individual candidate attractants needed to be added so as to obtain a blend maximally attractive to laboratory-reared An. gambiae. To determine whether wild mosquitoes would also be attracted to this synthetic odor blend and to compare it with whole humans under epidemiologically relevant conditions, field experiments were conducted inside experimental huts, where the blend was compared with 10 different adult male volunteers (20-34 years old). The blend attracted 3 to 5 times more mosquitoes than humans when the two baits were in different experimental huts (10-100 metres apart), but was equally or less attractive than humans when compared side by side within same huts. Conclusion and Significance: This highly attractive substitute for human baits might enable development of technologies for trapping mosquitoes in numbers sufficient to prevent rather than merely monitor transmission of mosquito-borne diseases. © 2010 Okumu et al.
ammonia; carbon dioxide; carboxylic acid; adult; article; controlled study; field experiment; human; male; mosquito; nonhuman; odor; Animals; Evaluation Studies as Topic; Host-Parasite Interactions; Humans; Mosquito Control