Seminar: "Functional characterization of mosquito host-seeking and oviposition repellents" - Ali Afify

Ali Afify, Ph.D.
Assistant Professor
Drexel University

Mosquitoes are vectors for many deadly diseases, including malaria which kills more than 400,000 people around the world every year. Mosquitoes primarily depend on their sense of smell (olfaction), in combination with other senses, to find hosts for blood-feeding and select their egg laying habitats. Therefore, olfactory cues such as repellents can be used to control mosquitoes and their disease. We used a combination of behavioral, imaging, and electrophysiology methods to investigate the mode of action of currently used host-seeking and oviposition repellents in the malaria mosquito Anopheles coluzzii. We found that some host-seeking repellents strongly activate small numbers of olfactory receptor neurons (ORNs) in the Anopheles mosquito antennae, while others work by reducing the volatility of human skin odorants leading to a decreased attraction. We also found that some oviposition repellents of Aedes aegypti mosquitoes also repel Anopheles mosquitoes. However, one Ae. aegypti repellent attracted Anopheles egg laying suggesting a species-specific effect. Interestingly, this odorant also killed Anopheles eggs suggesting it can be used as an attract-and-kill odorant. Overall, these findings will help guide decisions on choosing the right repellent for each mosquito species and stage, and will help develop safer alternatives to currently used mosquito repellents.