The heat this summer is unusual. Tropical nights appear in June, and heatwave warnings continue in July. In summer, mosquitoes of uninvited guests also seem to be particularly polarizing. A few days ago, mosquitoes were harassing me, so I grabbed an electric mosquito net that looked like a tennis racquet and caught it, and more than ten were electrocuted.
I tilted my head to see where the hell these guys came from, but I found out that the screen in the small room was slightly open. If so, does that mean that it flew to the 9th floor of the apartment and infiltrated it in a swarm? Normally, you will follow people up the elevator and come in when the front door opens. When I was a child, when I was living in a detached house, there seemed to be more flies, but now it is difficult to see them, so mosquitoes seem to have a superior obsession with people.
Because Paris is large and conspicuous, it is difficult to ride in the elevator, and since the target is food eaten by people, not people, there are many places to go, such as food waste, even if it is not a high-rise apartment. On the other hand, as a mosquito that needs to feed on animal blood to get the energy to lay eggs and lay eggs, the city will not be able to give up people. Mosquitoes have survived even in apartment forests thanks to evolving an amazing ability to track down prey (blood) bearers.
A lot of research has been done on how mosquitoes recognize the presence of humans, and it turns out that the most important thing is to detect carbon dioxide in the exhaled breath. Mosquito detects changes in the concentration of carbon dioxide carried in the air, guesses the existence of a source that is more than 30 meters away, that is, a person, and determines the direction of flight. On the 9th floor, it is around 25 meters, so it is within range.
The second most important clue following carbon dioxide is the smell of sweat, which detects lactic acid, ammonia, amines, carboxylic acids, ketones, and aldehydes in sweat. Many of the sweat odor components are not produced by human cells, but by microorganisms living on the skin. Similarly, even with sweat, it is easy for mosquitoes to be entangled by people with a high concentration of these odors.
But recently it has been discovered that mosquitoes use another clue to increase their chances of finding the right target. In February, the academic journal ‘Nature Communications’ found that mosquitoes that detect carbon dioxide and search for targets prefer red, orange, or black targets when they are with white targets. On the other hand, there was no such difference for purple, blue, and green. Interestingly, human skin ranges from pale orange to dark reddish-brown depending on race, so it falls within the mosquito-loving range. On the other hand, there was no difference in color preference in the absence of carbon dioxide. In other words, it chases a red or black target only when it is perceived as prey.
▲ Mosquitoes in summer are quite annoying, but as mosquitoes that can only lay eggs by sucking blood, finding someone is worth risking your life for. source wikipedia
Last month, in the academic journal Cell, the results of a study that revealed the virus’ strategy to increase infectivity by using the mosquito’s habit of chasing the smell of human sweat were published. In Korea, even if you are bitten by a mosquito, in most cases, the bite will only cause an itchy, red, swollen wound that lasts for a few days.
The most notorious of these pathogens is the malaria parasite, which still kills more than 600,000 people every year. Mosquitoes are also carriers of the virus that causes dengue fever, which kills regarding 40,000 people every year, and the Zika virus, which caused the fear of microcephaly newborns in Latin America a few years ago. But recently, it has been discovered that these viruses change the body odor of an infected person, making them more attractive to mosquitoes. It is a strategy to transmit the virus in the blood when a visiting mosquito sucks blood, and then infects the mosquito when it sucks the blood of the next person.
It was found that when infected with these viruses, the concentration of acetophenone in the sweat odor component increases, and as a result, more mosquitoes seek it out. Acetophenone is also made by skin microorganisms, and healthy people make a protein called RELMα to suppress the growth of this microorganism. When infected with a virus, the RELMα gene activity is lowered and the protein is not made properly, so microorganisms multiply, and as a result, the smell of acetophenone becomes strong. Interestingly, animal experiments on infected mice found that administration of vitamin A inhibited microbial growth, resulting in less acetophenone production.
Among those who are particularly prone to mosquito bites, there may be cases where vitamin A deficiency is the cause. Foods rich in vitamin A or precursors include liver, mackerel, mackerel, sweet potato, squash, kale, and carrots. Porridge is a food that is good for the body. If you take these foods for health management in the summer, wouldn’t it be possible to get the side effect of changing the body odor into a body odor that is less attractive to mosquitoes?
