What does measles actually do, and should you vaccinate against it?

はしかは何をするのか

Or is this just hysteria?

ワクチンは打つべきか

Measles is a virus:

騒ぎすぎなのか

a hull of proteins, RNA,

はしかはウイルスだ

plus some more proteins for reproduction.

ＲＮＡやタンパク質を持っている

It cannot reproduce by itself; it needs a host cell to do so.

増殖するには 宿主細胞が必要だ

To understand measles, we have to understand the immune system.

免疫を理解するところから始めよう

You might already have seen

免疫の動画はもう見たかな？

the visual system we developed to help here.

はしかに関連する部分を見ていこう

Now, let’s focus on the parts of the immune system relevant to measles.

はしかは鼻 口 目から体に入る

The measles virus enters humans through the nose, mouth, or eyes.

まず 肺から始まる

The measles infection starts in the lungs.

はしかは肺に入ると

Measles is especially good at infecting the body’s first line of defence:

マクロファージに感染する

macrophages, powerful guard cells that protect the lungs from intruders.

肺への侵入者を防ぐ護衛だ

They enter a cell and take it over.

これを乗っ取る

The virus reprograms the cell and

乗っ取られた細胞は

transforms it into a dangerous virus production center.

ウイルス生産センターに変わる

Once a cell is filled with viruses,

細胞一杯になると放出され

they leave the crippled cell and begin the cycle over again.

これを繰り返していく

But the immune system has powerful weapons against virus infections:

免疫系にも強力な武器がある

natural killer cells.

ナチュラルキラー細胞だ

These cells basically patrol the body and check other cells for infections.

体内を見回って守っている細胞で

If they find an infected cell, they order it to commit suicide.

感染を見つけると 自殺を促していく

This is so effective that for the first 10 days or so,

これは効果的で 10日ほどは

you will not even notice that you’re infected with measles.

感染したことに気づかない

And now, the reason why measles is so powerful.

だがここからが はしかの本領発揮だ

After a period of fighting and dying,

戦闘後 マクロファージは

macrophages alert the brain of the immune system:

樹状細胞に敵襲を伝える

the dendritic cells.

樹状細胞の仕事は 敵の情報を集め

The job of the dendritic cells is to collect samples of intruders,

強力な武器を活性化させ

travel to the lymph nodes,

仲間を奮い立たせることだ

and then activate the heavy weapons

だが はしかは恐ろしい戦術を使う

that eradicate the infection very fast in a team effort.

樹状細胞に感染し

But the measles virus uses a dreadful tactic.

体の奥へと進入するのだ

It infects the dendritic cells

味方の振りをしているため

and uses them as a Trojan horse to enter deeper into the body.

誰も気づかない

The infected cells travel to the next lymph node

リンパ節に着くと そこの

to alert other immune cells.

Ｔ細胞やＢ細胞に感染する

Once it arrives,

敵と戦うための部隊にだ

the measles virus spreads around the virgin T and B cells

感染はとても早い

and infects them.

リンパ系や血流から

It attacks the very system that evolved to fight it.

あちこちに広がっていく

Now, things happen very fast.

体中の臓器 脾臓や肝臓や腸

The lymph system spreads the virus everywhere

そして肺に感染する

and it enters the bloodstream,

症状も出てくる

infecting cells while traveling.

高熱 頭痛 吐き気 発疹だ

Measles infects organs like

部隊が勝ちかけていた肺に

the spleen, the liver, the intestines, and, most importantly, the lungs.

何百万ものウイルスが押し寄せ

The symptoms range from

壊滅させられる

a very high fever, headache, sickness, bronchitis, and, of course, a rash.

この時咳をすると ウイルスが飛ぶ

In the lungs, the immune system was doing pretty okay.

感染力は強く ワクチン接種なしだと

But now, millions of viruses attack a second time

90％の確率で感染してしまう

and kill countless cells, wiping out the defense systems.

肺を守る細胞がいなくなると

In this phase, you start coughing out millions of measles viruses.

他の感染症にかかりやすくなり

Measles is so contagious at this stage,

それが肺炎を引き起こす

that if you meet someone who isn’t vaccinated,

はしかの一般的な死に方だ

there’s about a 90% chance you’ll infect them.

免疫系は深刻な傷を負い

Without the protective army in the lungs, other bacteria or viruses that

防衛機能は壊れてしまった

would usually not stand a chance can now enter the lungs and develop into

ウイルスは体中の皮膚へと広がり

harmful parallel infections that can cause pneumonia,

感染が見た目にも現れる

the most common way to die from measles.

ウイルスが脳に達し

Your body’s immune system is now seriously wounded.

感染する場合もあり

Various protective systems are hurt and disrupted.

20％から40％の確率で死ぬか

The virus spreads everywhere, infecting the skin all over the body.

脳に長期的損傷が残る

The typical measles rash now becomes visible.

だが免疫系もまだ諦めず 反撃に出る

And in some cases, the measles virus

生き残った樹状細胞は

reaches the brain and causes a brain infection.

反ウイルス部隊を活性化し

If it does so, the chances of dying are between 20 to 40 percent,

形質細胞は抗体を大量に放出する

and there may be long-term damage.

ウイルスにくっついて固める

But your body is far from giving up at this stage,

小さなタンパク質だ

and it fights back agressively.

キラーＴ細胞は感染した細胞を殺し

Some dendritic cells survive long enough to activate

２～３週間後には

the anti-virus forces of the body.

感染は収まることになる

Plasma cells in the lymph nodes start producing billions of antibodies,

だが免疫系の回復には数ヶ月かかり

tiny proteins that mark infected cells for destruction

その間病気にかかりやすい

or clump the virus together.

免疫系はウイルスを忘れず

Killer T cells flood the body and kill infected cells left and right.

体には永久に免疫ができる

After 2 to 3 weeks, the body usually gets

はしかは甘くない

the upper hand and overwhelms the infection.

84％の人がワクチン接種しているが

But the immune system is now seriously weakened,

2014年には12万人が感染して死んだ

and may take weeks or months to recover,

接種できない人もいる

leaving the body vulnerable to other diseases.

化学療法中の人やＨＩＶ患者

But, if you make it, you are now immune:

アレルギーを持つ人たちだ

the immune system remembers the virus forever.

それ以外の人は接種しよう

Measles is no joke.

ワクチン接種は安全で 安く行える

Although 84% of all humans are vaccinated against measles,

はしかは怖い

122,000 people died because of the infection in 2014.

免疫の強化は必ずすべきだろう

Some people cannot get vaccinations,

接種否定派は 子どものためだと言う

either because they’re too young, because of chemotherapy or HIV,

しかし こう問う必要がある

or because they’re allergic to the vaccine.

はしかの危険は消えたのか？

They need the rest of us to stop the disease for them.

悲しいことに まだだ

The measles vaccination is safe, cheap, and available.

団結し このウイルスを撲滅しよう

There are no benifits from having measles at all.

怪物を正しい場所に追いやるのだ

You don’t strengthen your immune system and it’s not more natural.

歴史の本の中に

Most people who don’t vaccinate only want the best for their children,

Subtitles by the Amara.org community

which is honorable.

But if you ask yourself,

“Am I putting the life of my child and other children at risk by

not vaccinating against measles?”

The sad answer is yes. Yes, you are.

Let’s not play the blame game, though.

Let’s work together and eradicate this virus.

Together, we can get rid of these dreadful monsters and

consign them to their rightful place: the history books.

Subtitles by the Amara.org community