Welcome to brain Stuff from how stuff works. Hey, brain stuff, it's Christian Seger. If you're like most people, you hate mosquitoes. They're kind of the Andy Dick of the insect world, annoying and in some cases dangerous. If we rate animals by the number of deaths they cause, these little blood suckers top the charts by a wide margin, and this is due to their transmission of malaria and other harmful diseases.
And whether your next mosquito bite causes serious illness or intense frustration, we can all agree mosquitoes are just the worst. But are some people immune to mosquito bites? First, let's be clear mosquito bites aren't actually bites. When a mosquito lands on you, she uses her probosis. It's a long, double tubed mouthpiece to pierce your skin and get at the blood underneath. And yes, that's a sheet. Every single
mosquito that has ever bit you has been female. They bite you because they need a protein in your blood to develop their eggs. When a mosquito uses her antenna to sense the warm blood beneath your skin and then pops her probosis in to tap your capillaries. One of those tubes injects saliva, while the other one withdraws blood. The saliva contains enzymes that act as a mild painkiller and thins the blood to prevent clotting. Your body interprets
these enzymes as foreign invaders and produces histamine. Histamine binds to receptors in the bite area, dilating local blood vessels. This increased blood flow summons more white blood cells, and when you get too much histamine, the bite area can swell and redden, creating what's called a wheel. Yeah, wheel, that's the word of the day. Now, each person will react to a bite differently, and your allergies will vary.
So what makes a mosque to choose a certain person, Well, there are a number of factors, one of the biggest being that there are more than three thousand known varieties of mosquitoes and they're not all looking for the same thing. For those that dig a nice sip of human blood, smell,
body temperature, and genetics play huge roles. According to scientists at Rotterdam Research, each human body can produce anywhere from three hundred to four hundred distinct chemical odors, some of which are bug magnets and others they might be bug repellent. Research from a chemist named Ulrich Berner shows that mosquitoes are particularly fond of carbon dioxide that's released from exhalation and the skin, and they also like lactic acid, which
is present on our skin after exercise. Now, drinking beer, being pregnant, and being a bigger person can all also make you more active to mosquitoes. Diet and blood type surprisingly don't seem to matter so much. Everybody has these yummy chemicals on their body, but it seems that the people mosquitoes avoid produced higher amounts of repellent chemicals. Dr James Logan from Rotterdam set up a pretty weird experiment to see if he could find these all important repellent chemicals.
His team separated people into two groups, mosquito favorites and mosquito mez. They put these folks in body size foil bags to collect their odors for two hours, and they used a chromatograph to analyze the chemicals they had collected and hooked electrodes up to mosquito antenna to see what the bugs thought of each smell. They found about seven or eight made a difference. These odors were present insignificantly different quantities between those people who were attractive to mosquitoes
and those who weren't. Their study, published in the Journal of Medical Entomology, cited two chemicals as significantly repellent, one called six methyl five hepton to one, which apparently smells of nail polish remover, and another called jennal acetone, which has a kind of floral odor. As of this recording, the race to use these and other chemicals as a new superbug repellent is in full swing. So you probably know that bacteria is largely responsible for the various smells
of the human body. Each human being is home to a unique mix of trillions of microbes. It's sort of like a fingerprint. Now, our genes may play a large role in determining what sort of microbial life forms we end up posting in. A team led by doctor Manuela Fernandez Grandin tested the heritability of attractiveness to mosquitoes using twins. The twins would put a hand into either end of a sealed dome along with twenty female mosquitoes. Now don't worry,
they weren't allowed to bite. Researchers gave each subject an attractiveness score compared to the other hand, identical twins had consistently more similar scores compared to fraternal twins, so jeans do seem to play a role. This may be tough news for the or so of people that mosquitoes find
particularly attractive. If you're one of the local mosquito's favorite dishes, remember to keep some kind of bug repellent with you and to wear long sleeves and pants if the weather allows, especially in areas of the world where these bugs carried diseases like malaria or denge. And I suppose there's a little light at the end of this mosquito net tunnel here. Some people do have a chance of building up a tolerance after repeated mosquito bites, but for others, the allergy
just gets worse. Check out the brainstuff channel on YouTube, and for more on this and thousands of other topics, visit howstuff works dot com.