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Scientists build giant human-scented buffet to learn how mosquitoes find us

The researchers created A giant sniffing arena mosquitoes, all in the hope of understanding why they are so drawn to us. Among other things, they found that man body odor attracted insects more than the mere presence of carbon dioxide, a chemical we exhale.

Many studies have tried to figure out how female blood-sucking mosquitoes find and choose the people they feed on. But according to research author Conor McMeniman, it is often difficult to capture the complex nature of mosquito attraction in these studies. So, in partnership with researchers at the Macha Research Trust in Zambia, Africa, McMeniman and his team set out to create a more naturalistic setting for their experiments.

“In the lab, most of the studies used to test the scent preferences of mosquitoes are done on a very small scale, in small boxes of about 0.5 cubic meters or less,” said McMeniman, a malaria researcher at the Johns Hopkins Bloomberg School of Public Health. Research institute, Gizmodo reported. “For the study in Zambia, we used a design called a semi-field flight cage – a shielded structure with a volume of about 1,000 cubic meters, which is about 2,000 times the volume used for conventional laboratory analyses.”

The cage was equipped with evenly spaced heating pads that could heat up to typical human skin temperature (approximately 95 degrees Fahrenheit). On these pads, the team could also lure mosquitoes by releasing varying amounts of carbon dioxide and human scent. Luckily, the volunteers were safe as their scent came from the air from the single tents. they stayed inside. As a test subject, they used a human-loving and common malaria vector called Anopheles gambiensis.

The sheer size of the mosquito arena allowed the team to compare the scents of six people at once, McMeniman says, far more than the typical two scents used in similar comparative studies. It also allowed them to see how the mosquitoes would hunt at night, their preferred feeding time. At night, about 200 mosquitoes were released into the cage, where their activity was monitored using infrared cameras. If the beetles landed on the heating pad, it indicated they were ready to eat.

Anopheles gambiae mosquito.

Anopheles gambiae mosquito.
Image: RealityImages (Shutterstock)

The researchers found that body heat alone does not cause mosquitoes to run for potential food. Mosquitoes were attracted to the pads after carbon dioxide was added to the mixture. But of the three factors, body odor itself was the most attractive to bloodsuckers.

“In this study, we found that human odor is critical to Anopheles gambiensis be drawn into the proximity of a potential host, whereby they can detect heat from human skin,” McMeniman said. The team’s findings were published Friday in current biology.

However, as other studies have shown, the mosquitoes in this study had their clear favorites among humans. And in people’s individual musk, the team identified chemical components that seemed incredibly attractive or repulsive.

“The most attractive person had a distinctive odor with elevated levels of a number of light carboxylic acids in the air, as well as another chemical called acetoin, which is likely produced by the skin microbiome,” McMeniman explained. “Interestingly, the person who was least attractive in our test had an odor signature that was radically different from the other volunteers—he was enriched in a chemical called eucalyptol and depleted in a host of other airborne chemicals found in other volunteers who were more attractive. mosquitoes, including the carboxylic acids we found.”

These findings suggest that high levels of eucalyptus in the body can be very beneficial. restraining factor mosquito bites. It is likely that this person ate foods rich in the chemical commonly found in herbs and spices, the authors say. But it is also possible that he used external products containing it, such as toothpaste and mouthwash.

“Understanding which chemicals in human odor cause differential attraction to certain people is important because if we can identify these chemicals, we can help communicate personal bite risk,” McMeniman said. This research could also help scientists develop better baits or traps.

Additional Research required confirm command results. But this research is just the beginning. Job. Over the next few years, they plan to conduct larger experiments in Zambia that will involve more than 100 people. In the US, the team will try to better understand the entire library of chemicals that can be found in our fragrance. Tthey hope to eventually build a similar testing arena in the US to study native disease-spreading mosquitoes.

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