Deciphering New Cues and Receptors Used by Mosquitoes to Find People and Spread Disease
Two-step amplification cascade.
We are devising molecular genetic approaches to suppress populations of the mosquito vector, Aedes aegypti, which spreads Dengue, Zika, yellow fever and other diseases.
Aedes transmit dengue and other diseases afflicting 100-400 million people annually. These mosquitoes are spreading to many new parts of the world where Army troops are stationed. It is therefore of importance to understand the mechanisms that mosquitoes use to find people and spread disease. Female Ae. aegypti detect CO2 plumes from breath at distances of up to 10 meters. Then they become more active and use vision and olfaction to guide them to within ~20 cm, whereupon they sense convection heat and humidity from skin.
Over decades, no other cues have been found that mosquitoes use to target people. We propose two new human cues that A. aegypti use to home in on humans. The first is IR radiation. Humans emit ~10 mm IR from ~34°C skin. The second, unappreciated human cue that Ae. aegypti use to find people is speech. Aedes are most active during the day and therefore bite when people are awake. The main frequencies of speech (~100—800 Hz) coincide with the optimal frequencies for hearing in Aedes. The concept that mosquitoes can be attracted to vocalizations from their hosts is known for mosquitoes that feed on frogs. We have obtained exciting preliminary data supporting the proposal that Aedes are attracted to speech, and propose to characterize the precise sound frequency range used by mosquitoes to find people, and how the insects integrate speech with other attractive human cues.
Large numbers of Army personnel are located in regions with endemic insect-borne disease. The discovery of IR radiation as a robust attractive cue could lead to the implementation of Army uniforms that do not transmit IR, and therefore reduce their attraction to mosquitoes. These new discoveries could lead to the implementation of improved traps to suppress populations of mosquitoes.
