How can a virus overwhelm the very complex

怎麼會有一種病毒能夠

defense system of the body so quickly

在短時間內有效地摧毀

and so effectively?

如此複雜的免疫系統?

Let's take a look at what Ebola does.

就讓我們來看看伊波拉做了些什麼

(Theme music)

伊波拉是一種病毒

Ebola is a virus.

病毒非常小

A virus is a very small thing.

只由少量的RNA或DNA構成

A bit of RNA or DNA

一些蛋白質

and a few proteins

和一個外殼

and a hull.

它們單獨存在時，什麼事情都做不了

It has no ability to do anything

無論如何，

by itself whatsoever,

它們只能透過感染細胞來生存與繁殖。

and can only survive and proliferate by infecting cells.

為了避免這種事情發生，我們有免疫系統。

To avoid this we have the immune system.

免疫系統超級複雜

The immune system is super complex

所以我們畫一張圖表

so we develop a visual system

讓大家能輕鬆的了解。

that makes it easy to understand.

看起來像這樣：

So it looks like this:

讓我們忽略其他部分，只看最關鍵的地方

Let's concentrate on the part that is critical to understanding Ebola

來了解伊波拉

and ignore the rest.

通常樹突狀細胞會啟動免疫系統

So usually dendritic cells will activate the army

反病毒細胞，輔助細胞

of anti-virus cells, support cells

和製造抗體的細胞

and anti-body factories

與一般的守衛細胞一起工作

that work together with the guard cells

在幾天之內消滅病原體。

wipe out the infection in a matter of days.

但是，當伊波拉感染人體時

But when Ebola strikes, it directly

它們卻直接攻擊免疫系統。

attacks the immune system.

首當其衝的是樹突細胞，

Some of the first cells it takes over are

又稱免疫系統的總司令。

the dendritic cells, the brains of

伊波拉病毒和樹突細胞上的受體結合，以侵入細胞。

the immune system.

一旦進入細胞，伊波拉溶解了外殼並釋放

The Ebola virus enters a dendritic cell by

其遺傳物質，核蛋白和酵素。

binding into receptors for cell transport.

簡單來說，它控制了整個細胞

Once it is inside, it dissolves its outer hull and releases

關閉細胞的保護機制

its genetic material, nucleoproteins and enzymes.

並修改它

In a nutshell it takes over the cell,

結果細胞變成了傀儡，專門用於生產病毒

disables the cells protective mechanisms and

而細胞的資源更是被盜用，來生產新病毒

reprograms it.

當細胞資源耗盡，伊波拉將溶解細胞膜離開細胞

The cell now becomes a virus production machine

數以百萬計的病毒被釋放到組織中。

and uses its resources to build Ebola viruses.

該病毒不僅可以防止樹突狀細胞

Once the cell is saturated, it dissolves the cell membrane

啟動專一性免疫

and millions of viruses are released into the tissue.

它更能改變發送信號的蛋白質

The virus not only prevents the dendritic cells

使剛出生的專一性淋巴球

from activating the specialized and anti-virus forces,

過早地結束自己的生命。

it manipulates them into sending signal proteins

因此，免疫系統被嚴重破壞

that tricks specialized cells

而無法反擊。

into ending their own life's prematurely.

當病毒暴增，當然是指來到數十億個的時候

So the immune system is seriously disrupted

有一種細胞會殺死受感染的細胞，

and unable to react.

稱為自然殺手細胞，但它們也在

When the virus rapidly multiplies, we're talking billions,

能遏止病毒擴散之前，慘遭感染

there are cells that should deal with infected cells,

同時伊波拉也會感染

the natural killer cells, but they also get infected

身體的守衛細胞:

and just die before they can prevent

巨噬細胞和單核球，

the disease from spreading.

不僅使它們失去防禦功能，

At the same time Ebola infects

伊波拉也會透過它們發送一些信號，

the guard cells of the body

命令由細胞組成的血管

macrophages and monocytes,

釋放組織液到體內

not only managing to succumb them the defenses,

在正常狀況下，這是合理的，但在這狀況下

it also manipulates some to signal to

只會造成混亂。

the cells make up the blood vessels

所有體內的嗜中性白血球被

telling into release fluid into the body

由病毒和巨噬細胞發送的信號喚醒

Usually this makes sense, but in this case

然而，嗜中性白血球幾乎無法對抗病毒，

it just causes mayhem.

它們加入了不該的一場戰鬥，

All of the body's neutrophils are activated

然後開始做一些不該做的事

awaken by the virus and the macrophages signals

嗜中性白血球會發送更多信號到血管

then are not very effective against viruses and

使發炎反應加劇，而引起內出血。

should not be involve in this fight and

伊波拉病毒同樣也在身體的其他地方搞破壞

begin to do lots of stuffs they shouldn't do.

那就是肝臟。它們非常

The neutrophils signals to the blood vessels to

容易入侵肝臟

release more fluid causing internal bleeding.

並迅速殺死大量的肝細胞

Another area of the body Ebola

並導致器官衰竭和更多的內出血。

attacks is the liver. The virus finds it

剛才所說的所有事情，都會同時發生

very easy to enter the liver and

當病毒蔓延，這就像在身體的每一個地方都發生核爆。

it quickly stars killing lots of liver cells

身體的其中一個地方發生就已經夠難搞了

and causing organ failure and more internal bleeding.

但現在是每個地方都發生了。

And all those things are going on at the same time.

現在免疫系統的所有反應

As the virus spreads, it is like nukes exploiting every where.

反而對身體有害。

One (unintelligibly) in one region will be problem enough

病毒繼續擴散和蔓延

But now is starting to happen everywhere at once.

感染了越來越多的人體細胞

All the mechanisms of the immune system have evolve to

當然，身體不會坐以待斃

handle infections work against you.

免疫系統全力一搏，

And the virus continues to spread and spread.

將啟動細胞因子風暴

And finally begins to infect more and more body cells

這一種求救信號

while the body desperately struggles to stay alive.

使免疫系統背水一戰，

In a desperate last effort to turn untighted

然而這有助於將病毒避開損害，

the immune system launches a cytokine storm.

特別是在血管。

A cytokine storm is a S.O.S signal

矛盾的是免疫系統越健康，

that causes the immune system to launch all of its weapons,

對自已的身體傷害也越大。

all at once in a desperate kamikaze attack.

因此越來越多的血液離開血流。

This helps the virus to leave behind tons of collateral damage,

身體的每一個空腔都被血液佔據。

specially in the blood vessels.

身體變得嚴重脫水

Paradoxically the healthier the immune system,

剩下的血液不足以供給器官所需的氧氣

the more damage it can do to itself

所以細胞開始死亡。如果你變成這樣

More and more fluid leaves the blood stream.

你的死亡率將非常高。

Blood pours after every opening of the body.

感染者中，10人裡有6人死亡

You become seriously dehydrated

好，伊波拉聽起來超討厭。所以呢?開始發瘋尖叫慌了嗎?

that just not now blood left to supply the organs with oxygen

不，差得遠呢。

and cells begin to die. If you reach this point

伊波拉病毒的疫情透過報紙，YouTube影片

the chance of you dying is very high.

而被過度誇大，所以每個人都在談論伊波拉。

Currently six out of ten infected die from Ebola.

但目前只有一種途徑，才會感染伊波拉

Wow! Ok. Ebola is nasty. So it’s time to panic, right?

體液接觸，也就是

No, not even close.

碰觸到受感染者的體液。

The severity of Ebola gets paper sold and

所以不要像她一樣這樣做。

YouTube videos shared so everybody is talking about Ebola.

自2014年6月起伊波拉病毒已造成5000人死亡。

But currently the only way to get infected by Ebola

普通流感死亡數最高可達每年50萬人。

is to come into contact with the body fluid

瘧疾每年約100萬人。

whose person that shows the symptoms

每天3000人。 在你看這段影片時，已經死了10個。

Or from infected batch . So just don’t do that.

所以，即使是伊波拉病毒多麼可怕，

Ebola has killed 5,000 people since June 2014.

都不要自被嚇自己。媒體說伊波拉非常具有傳染性，

The common flu kills up to 500,000 people each year.

全是他們在炒作。 大可放心。

Malaria causes up to one million each year.

你可以點以上連結，來對免疫系統有更進一步的認識。

3,000 people every single day. Ten children since this video started.

中文字幕 楊庭愷 譯

So even if Ebola is terrible and scary,

don’t let yourself be scared. The most infectious thing about Ebola

is the media hype around it.

You could learn a bit more about the immune system though

Transcription made by Miriam Delgado

Subtitles by the Amara.org community