[김홍표의 과학 한 귀퉁이] Mosquitoes I didn’t want but became neighbors

Grass is mankind’s friend. Herbivores such as sheep and deer also feed on grass. Wheat and oats, which entered the human community in earnest in the Fertile Crescent, are also types of grass. Unlike trees that climb high toward the sun, grasses with a habit of spreading far and wide are especially fond of and follow humans who dig the ground without hesitation. Plantain, also known as the wretched cha-jeon (車前子), sprouts seeds when it is crushed by a wheel drawn by a person or a cow. surprising.

Mosquitoes, who spread their territory by chasing humans who set fires to make slashes, and cut down and clear trees, follow humans. You can tell by just looking at them flapping their wings and asking to accompany them when they walk on a secluded mountain path. At this point, we wave our arms in a gesture of refusal, but in vain. Not only does this dissipate heat and body odors further away, but it can also give mosquitoes a visual indication that uncovered skin is here.

No one likes mosquitoes. When we were young, we slept in a navy blue mosquito net every night to avoid encephalitis mosquitoes. Not to mention a human who likes to wage war, he was also willing to fight mosquitoes. This is because mosquitoes carry viruses and parasite-borne diseases. Malaria, yellow fever, and encephalitis are examples. In Africa, Sri Lanka, the United States and southern China, Vietnam, and areas near the equator such as the Suez Canal. In this war aimed at eradication, humans have not yet won.

It is not the case that mosquitoes killed people yesterday. It is said that Alexander the Great of Macedon, who built a great empire in B.C., also died of malaria. In the Campanha swamps in central Italy and in southern China, thousands of soldiers died of spleen swells from malaria infections. This is because the blood of the infected patient has been destroyed and the inflammation has progressed excessively. Surprisingly, mosquitoes also sucked up the blood of giant dinosaurs without hesitation. In the Jurassic period, when dinosaurs roamed, mosquitoes that appeared with wings began to cooperate with parasitic pathogens and take down large animals one by one. As soon as a female mosquito carrying an egg pierced the thick skin of a dinosaur to feed its young, the malaria parasite jumped into the gap. That was about 130 million years ago.

At first glance, mosquitoes are quite embarrassing. Of the 2,500 species of mosquitoes, very few have a blood-sucking habit, and infection with Plasmodium Malaria can kill the mosquito. It was difficult to fly with a heavy body that ate too much animal blood to raise eggs, and it was common to die by mistakenly eating DDT sprayed on the wall. Moreover, humans drop flying mosquitoes with their free hands. The cunning Plasmodium worms, like pine needles, create aromatic compounds to lure mosquitoes. Unicellular Plasmodium is now almost degenerate, but has chloroplasts. It means close to plants. But malaria, which has changed its lifestyle to rely on animal tissue and blood for food, no longer photosynthesize.

The growth rate and adaptability of the Plasmodium Parasite is quite surprising. At the moment of biting a person, about 10 thread-shaped malaria spores escaped from the mosquito’s snout and move directly to the liver. There the parasites metamorphose and increase their numbers. Regardless of the host who has spent a week in vain to make the antibody, a weapon, tens of thousands of parasites that are ready leave the liver abruptly and settle on the red blood cells. In red blood cells, which are incubators full of globin protein, the number of Plasmodium parasites is called trillions. There are so many numbers that your mouth will open.

Now, the patient lying in bed with repeated fever and chills does not have the energy to chase mosquitoes. Both malaria and mosquitoes are delighted and set out on their way in search of another swarm of hosts.

It seems that they have entered a lull for a while due to the outbreak of Corona 19, but even now, mosquitoes lay their eggs in stagnant water in waste tires, all over the world. In sub-Saharan West Africa, hundreds of thousands of children still die of malaria. In recent years, the number of vicious viruses and parasites riding on mosquitoes has increased even more. Zika virus, which causes microcephaly in newborns, threatens mothers, and yellow fever targets Asia. A new host is every parasite’s dream. Parasites prefer flying insects, migratory birds and poultry, and airplanes that travel long distances in a matter of seconds while sitting.

As the Earth’s atmosphere traps the sun’s heat and accelerates the water cycle, the Earth becomes hot and humid. Thanks to this, mosquitoes that have migrated to the north spend the winter in dense metro subways and septic tanks. Mosquitoes have become an inseparable neighbor of mankind, although mankind may not have wanted them.

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