WEBVTT - BrainStuff Classics: Are Some People Immune to Mosquitoes?

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<v Speaker 1>Welcome to brain Stuff production of I Heart Radio. Hey

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<v Speaker 1>brain Stuff, Lauren bog Obam here with a classic episode

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<v Speaker 1>from our previous host, Christian Sagar. I pulled this one

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<v Speaker 1>out today because the brain Stuff headquarters are in Atlanta,

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<v Speaker 1>and here in Georgia, we're getting our first mosquitoes of

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<v Speaker 1>the year. For me, that means I got a bunch

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<v Speaker 1>of bites when I ventured outside for a socially distant

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<v Speaker 1>walk yesterday. But are some people immune to mosquitoes? Hey

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<v Speaker 1>brain Stuff? It's Christian Sager. If you're like most people,

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<v Speaker 1>you hate mosquitoes. They're kind of the Andy Dick of

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<v Speaker 1>the insect world, annoying and in some cases dangerous. If

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<v Speaker 1>we rate animals by the number of deaths they cause,

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<v Speaker 1>these little bloodsuckers topped the charts by a wide margin.

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<v Speaker 1>And this is due to their transmission of malaria and

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<v Speaker 1>other harmful diseases. And whether your next mosquito bite causes

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<v Speaker 1>serious illness or intense frustration, and we can all agree

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<v Speaker 1>mosquitoes are just the worst. But are some people immune

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<v Speaker 1>to mosquito bites? First, let's be clear, mosquito bites aren't

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<v Speaker 1>actually bites. When a mosquito lands on you. She uses

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<v Speaker 1>her probosis it's a long, double tubed mouthpiece to pierce

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<v Speaker 1>your skin and get at the blood underneath. And yes,

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<v Speaker 1>that's a sheet. Every single mosquito that has ever bitten

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<v Speaker 1>you has been female. They bite you because they need

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<v Speaker 1>a protein in your blood to develop their eggs. When

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<v Speaker 1>a mosquito uses her antenna to sense the warm blood

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<v Speaker 1>beneath your skin and then pops her probosis in to

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<v Speaker 1>tap your capillaries, one of those tubes injects saliva while

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<v Speaker 1>the other one withdraws blood. The saliva contains enzymes that

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<v Speaker 1>act as a mild painkiller and thins the blood to

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<v Speaker 1>prevent clotting. Your body interprets these enzymes as foreign invaders

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<v Speaker 1>and produces histamine. Histamine binds to scepters in the bite area,

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<v Speaker 1>dilating local blood vessels. This increased blood flow summons more

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<v Speaker 1>white blood cells, and when you get too much histamine,

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<v Speaker 1>the bite area can swell and redden creating what's called

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<v Speaker 1>a wheel. Yeah, wheel, that's the word of the day. Now,

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<v Speaker 1>each person will react to a bite differently, and your

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<v Speaker 1>allergies will vary. So what makes a mosquito choose a

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<v Speaker 1>certain person well. There are a number of factors, one

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<v Speaker 1>of the biggest being that there are more than three

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<v Speaker 1>thousand known varieties of mosquitoes and they're not all looking

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<v Speaker 1>for the same thing. For those that dig a nice

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<v Speaker 1>sip of human blood, smell, body temperature, and genetics play

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<v Speaker 1>huge roles. According to scientists at Rotterdam Research, each human

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<v Speaker 1>body can produce anywhere from three hundred to four hundred

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<v Speaker 1>distinct chemical odors, some of which are bug magnets and

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<v Speaker 1>others they might be bug repellent. Research from a chemist

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<v Speaker 1>named ul Ric Burner shows that mosquitoes are particularly fond

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<v Speaker 1>of carbon dioxide that's released from exhalation and the skin,

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<v Speaker 1>and they also like lactic acid, which is present on

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<v Speaker 1>our skin after exercise. Now, drinking beer, being pregnant, and

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<v Speaker 1>being a bigger person can all also make you more

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<v Speaker 1>attractive to mosquitoes. Diet and blood type surprisingly don't seem

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<v Speaker 1>to matter so much. Everybody has these yummy chemicals on

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<v Speaker 1>their body, but it seems that the people mosquitoes avoid

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<v Speaker 1>produce higher amounts of repellent chemicals. Dr James Logan from

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<v Speaker 1>Rotterdam set up a pretty weird experiment to see if

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<v Speaker 1>he could find these all important repellent chemicals. His team

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<v Speaker 1>separated people into two groups, mosquito favorites and mosquito mez.

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<v Speaker 1>They put these folks in body size foil bags to

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<v Speaker 1>collect their odors for two hours, and they used a

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<v Speaker 1>chromatograph to analyze the chemicals they had collected, and hooked

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<v Speaker 1>electrodes up to mosquito antenna to see what the bugs

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<v Speaker 1>thought of each smell. They found about seven or eight

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<v Speaker 1>made a difference. These odors were present insignificantly different quantities

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<v Speaker 1>between those people who were attractive to mosquitoes and those

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<v Speaker 1>who weren't. Their study, published in the Journal of Medical Entomology,

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<v Speaker 1>cited two chemicals as significantly repellent, one called six methyl

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<v Speaker 1>five hepton to one, which apparently smells of nail polish remover,

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<v Speaker 1>and another called jennal acetone, which has a kind of

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<v Speaker 1>floral odor. As of this recording, the race to use

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<v Speaker 1>these and other chemicals as a new superbug repellent is

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<v Speaker 1>in full swing. So you probably know that bacteria is

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<v Speaker 1>largely responsible for the various smells of the human body.

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<v Speaker 1>Each human being is home to a unique mix of

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<v Speaker 1>trillions of microbes. It's sort of like a fingerprint now

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<v Speaker 1>our genes may play a large role in determining what

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<v Speaker 1>sort of microbial life forms we end up posting in.

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<v Speaker 1>A team led by doctor Manuela Fernandez Grandin tested the

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<v Speaker 1>heritability of attractiveness to mosquitoes using twins. The twins would

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<v Speaker 1>put a hand into either end of a sealed dome

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<v Speaker 1>along with twenty female mosquitoes. Now don't worry, they weren't

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<v Speaker 1>allowed to bite. Researchers gave each subject an attractiveness score.

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<v Speaker 1>Compared to the other hand, identical twins had consistently more

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<v Speaker 1>similar scores compared to fraternal twins, so jeans do seem

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<v Speaker 1>to play a role. This may be tough news for

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<v Speaker 1>the twenty or so of people that mosquitoes find particularly attractive.

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<v Speaker 1>If you're one of the local mosquito's favorite dishes, remember

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<v Speaker 1>to keep some kind of bug repellent with you and

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<v Speaker 1>to wear long sleeves and pants if the weather allows,

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<v Speaker 1>especially in areas of the world where these bugs carried

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<v Speaker 1>diseases like malaria or denga. And I suppose there's a

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<v Speaker 1>little light at the end of this mosquito net tunnel here,

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<v Speaker 1>some people do have a chance of building up a

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<v Speaker 1>tolerance after repeated mosquito bites, but for others, the allergy

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<v Speaker 1>just gets worse. Today's episode was written by Ben Boland

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<v Speaker 1>and produced by Tyler Claang. To hear more from Ben,

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<v Speaker 1>including jokes that have aged better than that, Andy dick

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<v Speaker 1>One at the top, a tune into his podcast Ridiculous History,

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<v Speaker 1>and of course, for more on this and lots of

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<v Speaker 1>other biting topics, visit house to works dot com. Brain

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<v Speaker 1>Stuff is production of iHeart Radio. For more podcasts for

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