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Anyone who has spent a summer night swatting mosquitoes, or a summer day scratching mosquito bites can agree: mosquitoes stink. But the scents produced by humans are an important part of what attracts mosquitoes to us.
In a scientific report published Friday, scientists built an ice skating test platform and drew in the scents of different people to help identify different chemicals in the body that attract these insects.
Mosquitoes are part of the fly family, and they usually feed on nectar. However, women preparing to produce eggs need an additional protein source: blood.
At best, a bite will leave you with an itchy red rash. But mosquito bites often turn fatal, thanks to the parasites and viruses that the insects transmit. One of the most dangerous of these diseases is malaria.
Malaria is a blood-borne disease caused by microorganisms that begin living in red blood cells. When a mosquito bites a person infected with malaria, it ingests the parasites along with the blood. After they form in the mosquito’s stomach, they “migrate to the salivary glands, and when the mosquito feeds again, it spits them out onto the skin of another host,” said Dr. Conor McMeniman, assistant professor of microbiology at Molecular. and immunology at the Johns Hopkins Bloomberg School of Public Health and the Johns Hopkins Malaria Research Institute in Baltimore.
Malaria in the United States In the last century, thanks to window screens, air conditioning, and improved sewage systems, mosquito larvae have been able to thrive in water, but the disease remains a threat to most of the world.
“Malaria still kills more than 600,000 people a year, mostly among children under 5 and pregnant women,” said McMiniman, the book’s senior author. A new study published in the journal Current Biology.
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“It causes a lot of suffering around the world, and part of the motivation for this research is to try and understand exactly how the mosquitoes that transmit malaria reach people.”
McMeniman, a postdoctoral researcher at Bloomberg and co-first author of the study, Drs. Diego Giraldo and Stephanie Rankin-Turner focus on the sub-Saharan African mosquito, Anopheles gambiae. They cooperated with Zambia. Macha Research TrustUnder the leadership of Scientific Director Dr. Edgar Simulundu.
“We were really inspired to try and develop a system where we could study the behavior of the African mosquito in its natural habitat, reflecting its native habitat in Africa,” McMeniman said. The researchers also wanted to compare the mosquitoes’ scents on different people, track the insects’ ability to track scents up to 66 feet (20 meters) away, and study their most active hours, between 10 a.m. and 2 a.m.
Researchers set up an ice rink-sized laboratory to help understand how mosquitoes that transmit malaria reach people.
To tick all these boxes, the researchers created a net facility the size of an ice rink. Dotted around the facility were six screened tents where study participants slept. The air from their tents, carrying participants’ unique breath and body odor, is pumped through long tubes into the main facility’s drinking pads, where it is filled with carbon dioxide to mimic a sleeping person.
In the main 20 by 20 meter facility, hundreds of mosquitoes treated the scent of the sleeping people with a buffet. Infrared cameras track the movement of mosquitoes to different samples. (The mosquitoes used in the study were not infected with malaria, and could not reach the sleeping people.)
The researchers found what many hikers can confirm: Some people are more attracted to mosquitoes than others. Moreover, chemical analysis of the air inside the tent revealed substances that cause odors, whether or not they attract mosquitoes.
The mosquitoes are attracted to airborne carboxylic acids, including butyric acid, a compound found in “curable” cheeses such as Limburger. These carboxylic acids are produced by bacteria on human skin and do not pay attention to us.
While the carboxylic acid attracts mosquitoes, the insects appear to be repelled by another chemical in the plant called eucalyptol. The researchers suspected that one sample with a high concentration of eucalyptus might be related to the diet of one of the participants.
Finding the correlation between the chemicals found in different people’s body odors and the mosquitoes’ attraction to those odors was “exciting and interesting,” Simulundu said.
“This discovery opens the door to lures or decoys that can be used in traps to disrupt the host-seeking behavior of mosquitoes, thereby controlling malaria pathogens in regions where the disease is endemic,” said study author Simulundu.
Dr. Leslie Voschal, a neurobiologist and vice president and chief scientific officer of the Howard Hughes Medical Institute, who was not involved in the study, was similarly enthusiastic. “I think it’s a very interesting study,” she said. This is the first experiment of its kind to be conducted outside a laboratory on this scale.
Vosshall examines another species of mosquito that spreads. Dengue fever, Zika And Chikungunya. as if The study was published last year In the journal Cell, she and her colleagues found that this mosquito species seeks out the scent of carboxylic acids produced by bacteria on human skin. It is a good thing that these two different species respond to the same chemical signals, because this makes it easier to create mosquito nets or traps in the board.
The study may not have immediate implications for avoiding bug bites at your next barbecue. (Vosshall notes that even scrubbing with unscented soaps doesn’t remove the natural odors that attract mosquitoes.) But the new paper, she says, “gives us some good clues about what mosquitoes use to hunt us, and what it is.” That is, it is important for us to take the next step.
Kate Golembiewski He is a Chicago-based freelance science writer who specializes in zoology, thermodynamics, and death. She hosts the comedy talk show “Scientist Walks into a Bar”.