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Mosquitoes are arguably the worst thing about the outdoors.
And if you’re the kind of person who just 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 that, 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 this 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 those proteins as foreign, so they weren’t sensitized.
But then, the pair regularly received between 100 and 150 mosquito bites,
every 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 mosquitoes.
So you probably can make yourself essentially immune to these bloodsuckers,
if 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 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.
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