Carbon dioxide (CO2) is one of the most universal compounds to which blood-feeding mosquitoes respond and is an essential component of all mosquito traps. However, the delivery of CO2 to traps in the field is a logistical and economic bottleneck that hinders the widespread utility. This could be resolved by the availability of a CO2 mimic that can be released together with attractive baits. While potential CO2 mimics have been identified for Aedes and Culex, they are not effective against An. gambiae or other malaria vectors. To address this, we will specifically target the molecular receptors that are active in Anopheline CO2 responses to identify effective CO2 mimics for An. gambiae and other malaria vectors.
Carbon dioxide (CO2) is one of the most universal kairomone compounds to which blood-feeding mosquitoes respond and not surprisingly, a range of studies on the olfactory behavior of the malaria vector mosquito Anopheles gambiae s.l. reveal that a blend of CO2 together with other characteristic compounds is consistently attractive to female mosquitoes. Remarkably, while CO2 is not an essential odorant for the anthropophilic Anopheles gambiae s.s. in the laboratory, semi-field and field studies indicate that CO2 is essential to lure the mosquitoes from a distance into the vicinity of a trap, where body-related odors then guide the insects to the trap entrance, the importance of CO2 in this trapping paradigm is at odds with the inherent difficulties and limitations in its delivery/incorporation into economically viable, long-lasting and highly efficacious odor-baits in which CO2 is an essential synergist to evoke this behavior. However, the bottleneck posed by the delivery of CO2 to mosquito traps could be resolved by the availability of other compounds that could act as robust CO2 mimic that can be released similarly as the synthetic odors, while studies in Aedes and Culex have identified just such a set of potential CO2 mimics, they are not effective against An. gambiae or other malaria vectors. To address this gap in the current trapping armamentarium, we will specifically target the molecular receptors that are active in Anopheline CO2 responses to identify effective CO2 mimics for An. gambiae and other malaria vectors.
