How can a virus overwhelm the very complex

どのように人体を攻撃するのか

defense system of the body so quickly

素早く 効果的に

and so effectively?

エボラの動きを見てみよう

Let's take a look at what Ebola does.

エボラはウイルスだ

(Theme music)

ウイルスは小さい

Ebola is a virus.

ＲＮＡやＤＮＡなどでできている

A virus is a very small thing.

それ自身では生きていけず

A bit of RNA or DNA

細胞に感染することで生きていく

and a few proteins

でも人間には免疫系がある

and a hull.

免疫系は超複雑だ

It has no ability to do anything

わかりやすく図にすると

by itself whatsoever,

こんな感じ

and can only survive and proliferate by infecting cells.

エボラに関するところに話を絞ろう

To avoid this we have the immune system.

さて 通常は樹状細胞という細胞が

The immune system is super complex

ウイルス対策を行っている

so we develop a visual system

他の細胞と部隊を作って 戦うのだ

that makes it easy to understand.

だがエボラは 直接これらを攻撃する

So it looks like this:

まず 免疫系の司令塔である

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

この樹状細胞を乗っ取る

and ignore the rest.

受容体にうまく取りいって侵入

So usually dendritic cells will activate the army

中に入ると 内側を溶かし

of anti-virus cells, support cells

自身の核たんぱく質 酵素を放出する

and anti-body factories

細胞を乗っ取り

that work together with the guard cells

その機能を書き換えるのだ

wipe out the infection in a matter of days.

細胞はウイルス生産工場となり

But when Ebola strikes, it directly

中身は材料として使われる

attacks the immune system.

生産し尽くすと 膜を破り

Some of the first cells it takes over are

何百万という仲間たちが放出される

the dendritic cells, the brains of

ウイルスは 樹状細胞以外の

the immune system.

細胞部隊にも働く

The Ebola virus enters a dendritic cell by

特殊な信号を送って騙し

binding into receptors for cell transport.

素早く死ぬように仕向ける

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

こうして免疫系は

its genetic material, nucleoproteins and enzymes.

何も反応できずに壊される

In a nutshell it takes over the cell,

そしてエボラは急速に増殖　10億倍だ

disables the cells protective mechanisms and

そんな時はナチュラルキラー細胞だ

reprograms it.

が それもいずれはやられてしまう

The cell now becomes a virus production machine

体を守る細胞にも感染する

and uses its resources to build Ebola viruses.

マクロファージや単球だ

Once the cell is saturated, it dissolves the cell membrane

それらの防御機能を回避し

and millions of viruses are released into the tissue.

さらには操って 血管を攻撃させる

The virus not only prevents the dendritic cells

すると血液が漏れる

from activating the specialized and anti-virus forces,

よくあることだが この場合はまずい

it manipulates them into sending signal proteins

白血球はウイルスと戦うものだが

that tricks specialized cells

エボラはこれを妨害

into ending their own life's prematurely.

白血球は戦うことができず

So the immune system is seriously disrupted

その働きも失われる

and unable to react.

血管を塞ぐこともできず

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

内出血が起こる

there are cells that should deal with infected cells,

他には 肝臓も攻撃される

the natural killer cells, but they also get infected

中が容易に侵食され

and just die before they can prevent

肝細胞が死んで臓器不全になり

the disease from spreading.

内出血も発生だ

At the same time Ebola infects

これらが 同時に進行する

the guard cells of the body

あちこちで核が爆発するようなもの

macrophages and monocytes,

ひとつでも大問題なことが

not only managing to succumb them the defenses,

一度にたくさん起こるのだ

it also manipulates some to signal to

最後には 自身の免疫系があだになる

the cells make up the blood vessels

ウイルスが広がりに広がり

telling into release fluid into the body

体中の細胞に感染しだすと

Usually this makes sense, but in this case

生き残りが絶望的となり

it just causes mayhem.

免疫系は最後の手段に出る

All of the body's neutrophils are activated

サイトカインストームだ

awaken by the virus and the macrophages signals

ＳＯＳを発し

then are not very effective against viruses and

自身が武器となり攻撃する

should not be involve in this fight and

カミカゼアタックだ

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

強力であるが

The neutrophils signals to the blood vessels to

血管に対し深刻な被害をもたらす

release more fluid causing internal bleeding.

そして 免疫系のこの攻撃が

Another area of the body Ebola

致命傷になる

attacks is the liver. The virus finds it

血液が溢れ出て

very easy to enter the liver and

体のあちこちから出血

it quickly stars killing lots of liver cells

脱水症状にもなり

and causing organ failure and more internal bleeding.

血液が酸素を運べなければ

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

細胞が死ぬ

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

ここまでいくと ほぼ死ぬことに

One (unintelligibly) in one region will be problem enough

現在 致死率は６割程度だ

But now is starting to happen everywhere at once.

わお エボラって怖い

All the mechanisms of the immune system have evolve to

だがまだ慌てるような時間じゃない

handle infections work against you.

エボラの情報を皆で共有し

And the virus continues to spread and spread.

エボラについて理解しよう

And finally begins to infect more and more body cells

現在 エボラの感染経路は

while the body desperately struggles to stay alive.

感染した人や液体への

In a desperate last effort to turn untighted

接触と考えられている

the immune system launches a cytokine storm.

なので そうしないように

A cytokine storm is a S.O.S signal

エボラは今年5000人を殺害

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

インフルエンザは年に50万

all at once in a desperate kamikaze attack.

マラリアは100万人だ

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

動画が始まってから10人は死んでる

specially in the blood vessels.

エボラは確かに怖いけど

Paradoxically the healthier the immune system,

感染は多くない

the more damage it can do to itself

一番感染してるのはメディアかもね

More and more fluid leaves the blood stream.

さあ 免疫について学ぼう！

Blood pours after every opening of the body.

Subtitles by the Amara.org community

You become seriously dehydrated

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

and cells begin to die. If you reach this point

the chance of you dying is very high.

Currently six out of ten infected die from Ebola.

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

No, not even close.

The severity of Ebola gets paper sold and

YouTube videos shared so everybody is talking about Ebola.

But currently the only way to get infected by Ebola

is to come into contact with the body fluid

whose person that shows the symptoms

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

Ebola has killed 5,000 people since June 2014.

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

Malaria causes up to one million each year.

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

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