Mosquitoes kill hundreds of thousands of people each year, the most vulnerable people: children, pregnant women…

蚊子每年使數千人死去，最脆弱的人們：孩子、孕婦等...

No other bite kills more humans—or makes more of us sick.

蚊子的叮，使得無數人類死去或生病。

[Anopheles gambiae, Malaria] [Andes aegypti, Zika, dengue fever, chikungunya] [Culex pipiens, West Nile Virus disease]

[瘧蚊，瘧疾] [埃及斑蚊，茲卡病毒、登革熱、屈公病] [尖音家蚊，西尼羅熱病]

So what makes a mosquito's bite so effective?

究竟是什麼讓蚊子叮那麼厲害？

For starters, they're motivated.

首先，它們有動力驅使。

Only females bite us—hey need blood to make eggs.

只有母蚊會叮人，它們需要血液來產卵。

And a pool of water for their babies to hatch in.

加上一池水讓卵能夠孵化。

Even a piece of trash can hold enough.

就算是垃圾裡的積水也可以。

At first glance, it looks simple: this mosquito digging her proboscis into us.

乍看之下，感覺很簡單，蚊子把口器刺進我們體中內。

But the tools she's using here are sophisticated.

但它用的工具可是相當成熟。

First, a protective sheath retracts—see it bending back?

首先，它們有一個會收縮的保護鞘，看到它向後彎了嗎？

If you look at a mosquito's head under a microscope, you can see what that sheath protects.

如果用顯微鏡觀察蚊子的頭部，你就會看到那個鞘是在保護什麼。

And inside there are six needles.

而裡頭有六根針！

Two of them have tiny teeth.

其中兩根有小鋸齒。

She uses those to saw through the skin.

母蚊用它們來鋸開我們的皮膚。

They're so sharp you can barely feel her pushing.

它們非常銳利，銳利到你可能都感覺不到。

These other two needles hold the tissues apart while she works.

這兩根針則是會撐開組織，讓母蚊能做事。

From under the skin, you can see her probing, looking for a blood vessel.

從皮膚底下觀察，你可以看到她正在四處探尋，尋找血管。

Receptors on the tip of one of her other needles pick up on chemicals that our blood vessels exude naturally and guide her to it.

在其中一支針的針頭有受器，會接收人體血管所自然散發的化學物質，並引導母蚊至血管處。

Then she uses this same needle like a straw.

然後母蚊再把它當成吸管來吸血。

As her gut fills up, she separates water from the blood and squeezes it out.

當她身體裝滿了，她就會把水分與血液分開，並把它排出。

See that drop?

看到了嗎？

That frees up space to stuff herself with more nutritious red blood cells.

這能讓母蚊騰出更多空間給營養的紅血球。

With another needle, she spits chemicals into us.

另一根針讓它能向我們注射化學物質。

They get our blood flowing more easily, and give us itchy welts afterwards.

這會讓我們的血液更容易流動，並在之後留下會癢的腫包。

And sometimes, before she pries herself away, she leaves a parting gift in her saliva.

而有時，在母蚊偷偷離開之前，她會在口水裡留下一個離別禮物給我們。

A virus or a parasite that can sicken or kill us.

那就是病毒或寄生蟲，會讓我們生病甚至死亡。

There's nothing in it for her.

這對母蚊沒什麼好處。

The viruses and parasites are just hitching a ride.

病毒與寄生蟲只是搭便車而已。

But this is what makes mortal enemies out of us and mosquitoes.

但這就是人類和蚊子成為宿敵的原因。

They take our blood.

它們奪走我們的血。

Sometimes we take theirs, but often, not soon enough.

有時我們奪走它們的，但常常，我們的動作還是不夠快。

Good—you're still there!

很好，你還在。

These are the larvae of Culex pipiens, a.k.a. the common house mosquito here in California.

這是尖音家蚊的幼蟲，也就是加州最常見的家蚊。

Gross, right? Well, you can avoid them by emptying your rain gutters.

很噁吧？如果不想看到，就記得定時清理排水溝。

Pet water dishes too.

寵物的水盆也是。

While you're at it, subscribe!

去做這些事之前，記得訂閱！

We have so many more science videos coming your way. See you next time!

我們還有更多科學相關的影片，下次見囉！