
How Mosquitoes Sniff Out Human Sweat To Find Us - furcyd
https://www.npr.org/sections/health-shots/2019/03/28/706838786/how-mosquitoes-sniff-out-human-sweat-to-find-us
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rando444
This follows with one of the most effective mosquito repellents already in use
today. A rotating fan.

It mixes everything in the room around so that the carbon dioxide, sweat, and
everything else can't be as easily used to target you.

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huffmsa
A good breeze, doesn't have to be that strong, really helps outside.

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xavivives
It seems relevant to point out that there are two types of sweat glands [1].
And they secrete different stuff:

"Eccrine sweat is clear, odorless, and is composed of 98–99% water; it also
contains NaCl, fatty acids, lactic acid, citric acid, ascorbic acid, urea, and
uric acid. Its pH ranges from 4 to 6.8. On the other hand, the apocrine sweat
has a pH of 6 to 7.5; it contains water, proteins, carbohydrate waste
material, lipids, and steroids. The sweat is oily, cloudy, viscous, and
originally odorless; it gains odor upon decomposition by bacteria. Because
both apocrine glands and sebaceous glands open into the hair follicle,
apocrine sweat is mixed with sebum."

The article mentions acid lactic as a signaling metric. Only the Eccrine
glands sweat contains it.

This explains why the no-correlation between strong oddor (casused by the
apocrine sweat).

[1]
[https://en.wikipedia.org/wiki/Sweat_gland](https://en.wikipedia.org/wiki/Sweat_gland)

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est31
Some east Asian populations have no or almost no odour at all:
[https://en.wikipedia.org/wiki/ABCC11](https://en.wikipedia.org/wiki/ABCC11)

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huffmsa
It's both interesting and expected that we're only just now really getting a
grasp on mosquito targeting. Viruses and bacteria tend to have single targets,
easier for us to figure out, whereas more complex mosquitoes logically have
more complex targeting systems. We'll probably have it sorted in a decade.

Now, as for my unique anecdotal contribution:

I 1) don't attract many mosquitoes but 2) when one of them does find its way
to me, I'm non-reactive (no itchy bump). I'm both a sweaty and oily person,
but I don't really produce BO. No stinky armpits (I save a fortune on
deodorant), no stinky feet, etc. My father has a similar situation and he's
non-attractive for them, but my siblings are less sweaty, but do produce BO
and get eaten alive.

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EForEndeavour
> I 1) don't attract many mosquitoes but 2) when one of them does find its way
> to me, I'm non-reactive (no itchy bump)

There's potential for bias here: (2) might be over-inflating your impression
of (1). An alternative hypothesis (not trying to contradict your own
experience!): you attract mosquitoes as much as the next person, but since
you're nonreactive, you simply don't notice that mosquitoes are bothering you
unless you happen to catch them in the act of biting you (which they're good
at avoiding), or if you see or hear one flying around you (which could be
chalked up to random flight, or them having trouble locating you).

> I'm both a sweaty and oily person, but I don't really produce BO

Another comment on this story
([https://news.ycombinator.com/reply?id=19535422&goto=item%3Fi...](https://news.ycombinator.com/reply?id=19535422&goto=item%3Fid%3D19513708%2319535422))
points out that mosquitoes home in on lactic acid, which is produced by non-
odour-causing eccrine sweat glands, which explains why there is actually no
correlation between human-perceptible body odour and mosquito attractiveness.

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timkpaine
I am a very sweaty person, and I always get destroyed by mosquitos more than
those around me. It's funny how sometimes meaningful research merely confirms
things people already believe to be "obvious".

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beagle3
I used to be a very sweaty person, but always had less moquito bites than
those around me (though I did have quite a bit if I was alone). So it's far
from trivial.

(And preepting the question: I stopped being ultra sweaty after a 20 day
water-only fast, never to be sweaty again)

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gcatalfamo
You only had water for 20 days? How do you do that?

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beagle3
Appetite goes away after 48 hours or so, and then it’s easy until appetite or
hunger come back, which take 3-40 days depending on your health, fat reserves,
etc.

I had lost my appetite that time, so even first two days were easy.

On phone, so hard to google, but there have been a few we’ll documented cases
of people going a whole year with just water, vitamins and ridiculously little
protein (losing 100-250 pounds of fat in the process).

Also google valter lungo - fasting 2-3 days at a time is very healthy for you.

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simonsarris
For onlookers,
[https://en.m.wikipedia.org/wiki/Angus_Barbieri's_fast](https://en.m.wikipedia.org/wiki/Angus_Barbieri's_fast)

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TheSpiceIsLife
So can we now build a decoy that emits CO2, human sweat odour, and heat, that
traps and kills mosquitos?

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choonway
We can just as easily build a drone that senses CO2, humans sweat odour and
heat, that kills humans.

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TheSpiceIsLife
I’d suggest that may cause some legal difficulties.

Or military interest.

It could also lend itself to a new interpretation of the term SWATing.

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DantesKite
Probably explains why (anecdotally) white vinegar is so effective at repelling
mosquitos.

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dao-
This makes sense. I use white vinegar to treat a skin disease. It changes the
acidity of your sweat, which then affects what bacteria can flourish on your
skin. It's the bacteria that produce the smell.

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skosch
Read the article – it's bacteria that produce the smell humans perceive as
"sweaty", but it's not that smell that attracts the mosquitoes, but rather
acidic compounds that are already present in our sweat.

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tmp192489
Any reason why some people seem to attract mosquitos more than others? Is it
really just sweatiness or something else in a person's blood or scent?

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flurdy
I am not convinced it is _just_ sweat. But it may be a contributing factor.

My father grew up on a farm in a part of the world with _a lot_ of mosquitos.
He says he would work in the fields all summer shirtless and never even notice
any mosquitos.

I hate going there in the summer because of the little bastards. (And the
horseflies, I really hate them).

Wind forward 50 years of mostly city living in other parts of the world, and
whenever he flies back to his childhood home for a few weeks holiday he gets
eaten alive.

His blood type has not changed. He may be more sweaty as he is a little
chubbier, but he was probably quite sweaty working in the fields as a kid as
well.

I suspect it has to do with lifestyle. For him (and me) mostly working in
office environments for most of the year for many years, makes your
skin/odour/heat different than if you were an outdoorsy person that has a more
hardened skin that is less attractive to mossies. Perhaps.

That said I don't really hear of anyone that lives in the mosquito heavy area
that is susceptible to them whether they are office or farm people. Only
_outsiders_. That may be self-selecting as they would move away though.

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yomly
Diets have changed considerably since then too

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doodlebugging
This might be a great opportunity to try to understand why Avon Skin-so-Soft
functions as an effective repellent when other purpose-developed products
fail. Perhaps looking closely at the components in the SsS mix to see which
masks the lactic acid signal would be a good place to start.

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NicoJuicy
I know a guy that has a small DNA mutation.

Musquittos died when bit him ( his parents have it to). I haven't seen it in
real life, but he was an honest it guy. So I give him the benefit of the doubt

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ssener2001
It is understood from this these animals are created for biting human beings
and sucking from our body. Maybe there are some benefits we may does not know

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darkpuma
Sounds like a _naturalistic_ fallacy and/or a _just world_ fallacy.

There's not a silver lining to everything. Some things just suck. Nature is
brutal, not caring. Many relationships between organisms are purely parasitic,
exploitative, not symbiotic. If you really want a downer, look up what some
varieties of the cordyceps parasitic fungus do to ants.

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lorenzhs
For anyone else not familiar with cordyceps fungi, here's a three-minute clip
from BCC Planet Earth:
[https://www.youtube.com/watch?v=XuKjBIBBAL8](https://www.youtube.com/watch?v=XuKjBIBBAL8)

