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  • Mosquitoes are arguably the worst thing about the outdoors.

  • And if you're the kind of person who seems to be eaten alive every time you step outside,

  • you might have wondered if there's some way you could become immune to their bites.

  • Well, I have some good news.

  • You probably can, because mosquito bites are just a kind of allergic reaction.

  • But, like any allergy, the only way to become desensitized is with repeated exposure.

  • And I'm not talking about a few bites.

  • I'm talking about thousands of them over months.

  • When a mosquito bites, she injects you with a chemical cocktail that helps numb the area and keeps your delicious blood flowing.

  • The chemicals themselves don't cause the redness, swelling, or itching, though.

  • Your immune system's overreaction to them does.

  • Which is why mosquito bites are considered a kind of mild allergic reaction.

  • Your immune system learns to recognize these proteins as foreign,

  • and it primes specialized cells so the next time you're bitten, your body can launch a rapid immune attack.

  • This is what's known as sensitization.

  • Specifically, mosquito proteins tend to activate the production of two kinds of immune weapons: IgE and IgG antibodies.

  • When these antibodies bind to mosquito proteins, they ramp up the release of the molecule histamine,

  • and, ultimately, that causes those wonderful itchy bumps.

  • These antibodies can also cause much worse allergic symptoms, though, including full-on anaphylaxis.

  • Exactly why severe reactions happen in some people and not others is something doctors are still trying to figure out.

  • But what we do know is that, for the most part, if you can become sensitized to something, you can also become desensitized to it.

  • The trick is to induce your allergic response so frequently that you end up convincing your body that reacting is a waste of energy.

  • That's the basic principle behind allergy shots, also called specific immunotherapy.

  • Doctors have developed standard protocols for allergens like pet dander and pollen.

  • But we know the same idea works with mosquito bites, too.

  • For example, the older you are and the longer you live in the same place, the less your reaction to bites from local mosquito species tends to be.

  • But given that, you might wonder why, since you get bitten all the time, you haven't become totally desensitized yet.

  • Well, that's because even if you get bitten a lot, it's probably not enough.

  • If your goal is basically no reaction at all, that takes a lot of bites.

  • Like, so many.

  • In a prospective study from 1998,

  • researchers took a healthy 23-year-old man and an unlucky rabbit and exposed them to a species of mosquito neither had been bitten by before.

  • As expected, since it was their first encounter with that insect's unique blend of allergens, neither reacted much at first.

  • Their bodies hadn't yet learned to recognize these proteins as foreign, so they weren't sensitized.

  • But then, the pair regularly received between 100 and 150 mosquito bitesevery two weeks for the person and weekly for the bunny.

  • Over the first several weeks, the bite reactions became larger and more uncomfortable.

  • But, these brave mammals kept at it.

  • And after 20 weeks of this, the skin reactions noticeably declined.

  • By week 26 or so, both the man and the rabbit were basically reaction-free.

  • That sounds awesome, but if you do the math, it took between one and two thousand bites over half a year for the man to get to that point.

  • That's just way more than anyone normally gets in a summer.

  • Of course, since the guy in the study was just one guy,

  • there could be variation between people and how many bites are needed or how long the bite regimen has to go on for.

  • It's also unclear how long this desensitization lasts without maintenance doses of the allergens.

  • But if nothing else, we do know that long-term desensitization is possible because this one guy isn't the only person to become tolerant to bites.

  • Biologists that raise large colonies of mosquitoes for research often feed them with their own blood,

  • sometimes receiving hundreds of bites at a time, without reacting at all.

  • And studies suggest somewhere between 10 and 30 percent of people are just naturally tolerant to the bites from their local mosquito.

  • So, you probably can make yourself essentially immune to these bloodsuckersif you are willing to be bitten frequently for a long time.

  • We are not recommending that you do that.

  • We are not doctors, and this is definitely the kind of thing that you should talk to an allergist about,

  • especially if you're someone who has more severe reactions to mosquitoes.

  • Besides, it might not be too long before your allergist can help you get rid of those welts without thousands of bites.

  • Specific immunotherapy for mosquito bites has been tested, and clinical trials have found it to be quite effective.

  • But, also, there are some reasons you might not want to be completely unaware you're getting bitten.

  • Mosquitoes vector diseases, including a lot of really nasty ones, so, really, you want to avoid bites whenever possible.

  • Having those bites show up and annoy you can serve as a warning that your anti-mosquito efforts aren't effective.

  • So, maybe some itchy bumps every summer is a small price to pay to keep you vigilant against the diseases mosquitoes transmit.

  • And you can always stock up on citronella and deet instead.

  • Thanks for watching this episode of SciShow.

  • If all of this talk about mosquitoes has made you wonder why we have not just killed all of the mosquitoes to solve our problems,

  • we've got an episode all about that that you can watch next.

Mosquitoes are arguably the worst thing about the outdoors.

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