Researchers find "chemical stealth" against mosquito bites
Mosquitoes identify their food sources via olfactory cells, which can perceive both human skin and exhaled carbon dioxide. The anti-mosquito remedies available to date therefore only help to a very limited extent against mosquito bites and the diseases transmitted by them, such as malaria or dengue fever. However, US researchers recently made a breakthrough in the development of an anti-mosquito drug. They discovered aromas that block the olfactory cells of mosquitoes. The scientists will present their results in the "Cell" magazine.
To protect against mosquitoes, the olfactory cells of the animals are blocked. If the olfactory cells of mosquitoes are blocked, humans will no longer be able to perceive them as a source of food. Genevieve Tauxe and her colleagues from the University of California at Riverside took advantage of this by looking for a flavoring that turns off the animals' olfactory cells. To this end, the researchers examined more than 440,000 substances, some of which could be used as a “chemical camouflage cap”. They tested the flavors on the two mosquito species Anopheles gambiae, which transmits malaria, and Aedes aegypti, which releases the viruses of dengue and yellow fever to their hosts.
Earlier studies had already shown that carbon dioxide is perceived by mosquitos via so-called cpA neurons. Tauxe and her team have now found that other fragrances in human skin can also be identified by animals via these olfactory receptor cells. “We found that the CO2-sensitive olfactory cells from Aedes aegypti and Anopheles gambiae are also a sensitive detector for the odorants in human skin. We show that the activity of these neurons is important for the attraction of the skin odor and that they are the central target for intervention, ”the researchers write in the specialist magazine.
Different flavors protect against or attract mosquitoes The researchers discovered various substances, some of which blocked the olfactory cells of the mosquitoes and others activated them. For example, ethyl pyruvate switches off the rezepor so that the substance - applied to the skin - means that mosquitoes can no longer perceive the smell of the skin. As the researchers report, the agent approved as a flavoring agent has a pleasant smell. On the other hand, cyclopentanone, activates the olfactory cells so that the substance can be used to attract animals to mosquito traps.
"Our analysis opens up very realistic options for using simple, natural, cheap and pleasant flavors to prevent mosquitoes from finding people," explains study leader Anandasankar Ray, according to a report by "Cell Press".
The researchers' results could help curb the spread of malaria, dengue and other mosquito-borne diseases. This would particularly benefit Asia and Africa, where the diseases are widespread. According to the World Health Organization (WHO), around 220 million people worldwide contracted malaria in 2010 and around 660,000 patients died from the consequences of the disease. (ag)
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