But when it comes to some diseases, the way the body defends itself can have unintended consequences.

但說到某些疾病，身體自我防禦的方式會產生意外的後果

In the case of pneumonia, the immune system's response can be lethal, earning it the nickname

在肺炎的情況下，免疫系統的反應可能非常致命，因此又有

the 'captain of the men of death.'

「死神隊長」的稱號

Pneumonia doesn't just refer to a single virus or bacteria.

肺炎不僅是指單一病毒或細菌

It's a condition that can actually be caused by a number of different bacteria, viruses,

實際情況可能是由許多不同的細菌、病毒

or even fungi, the most common being the bacteria streptococcus pneumoniae, who will be our main bad guy today.

甚至是真菌所引起，最常見的就是肺炎鏈球菌，也就是今天要談的主要敵人

So when we're talking about pneumonia, we're really referring to something that is happening to our lungs.

因此，我們在討論肺炎時，實際上指的是肺部正在發生的事

Hi, my name's Keith Klugman.

嗨，我是 Keith Klugman

I'm the director of the pneumonia programs at the Bill & Melinda Gates Foundation.

我是比爾與美琳達．蓋茲基金會，肺炎計畫的主任

I'm particularly fascinated by pneumonia and have been working to try and prevent pneumonia in poor children all of my life.

我對肺炎特別著迷，而且在人生中致力於預防貧困兒童的肺炎

So pneumonia is an infection of the lungs and it is a very common infection.

肺炎是種肺部感染，而且是非常普遍的感染

The problem is that the lungs are thought to be sterile...in fact the lungs aren't sterile.

問題是，一般認為肺部是無菌的，但事實上並不如此

But generally there's very few bugs in your lungs. The problem is that our

但通常你的肺部很少有細菌。問題是

mouth and our nose are actually filled with bacteria and viruses and these can sometimes

我們的嘴巴和鼻子其實充滿了細菌和病毒，這些有時會

get down into the lungs.

進入到肺部

We're constantly being exposed to the bacteria and viruses that cause pneumonia like Streptococcus pneumoniae.

我們經常接觸到，引起肺炎鏈球菌等肺炎的細菌和病毒。

These pathogens can live in your upper respiratory tract without you even knowing it.

在你不知情的情況下，這些病原體會住在你的上呼吸道

And that's because, for most people,

這是因為，對大多數人來說

the immune system should be able to step in and stop them in their tracks, leading to immunity.

免疫系統應該能介入並阻止它們進入呼吸道，從而產生免疫

So you become immune to the bugs that you encounter when you're very young and by about

因此，在你小時候，你就會對碰到的細菌產生免疫

five years of age, you're pretty much immune.

大約五歲時，你就完全免疫了

But, for children under 5, the immune system is weaker, leaving the body susceptible to infection.

但對五歲以下的小孩來說，免疫系統較薄弱，容易受感染影響

And it's not just children who are at risk.

而不只是小孩會面臨風險

Then, unfortunately, pneumonia risk comes back again in the elderly.

然後，不幸的是，老年人還會出現肺炎風險。

"Who is elderly?" you might say.

你可能會問：「老年人是指？」

Generally defined as people older than the speaker.

通常定義是比現在說話的人還大。

So, for me, it's 65 and older…

所以說，我是 65 歲，以及更老的人......

So pneumonia is a disease of the extremes of life, the very young and the very old.

肺炎是種極端的生命疾病，很年輕也很老

Now, it's not only young children and older adults, anyone with a compromised immune system is at risk.

不只是小孩和年長的成人，任何免疫系統受損的人都有風險

With the immune system unable to mount a defense in the respiratory tract, the bacteria are able to pass into the lungs.

由於免疫系統無法在呼吸道中進行防禦，細菌就能進入肺部

Once there, the immune system will still try to defend the body.

一旦到了那地步，免疫系統仍會試圖保護身體

But...

但......

Unfortunately, they have a lot of side effects when this response occurs.

不幸的是，這種反應發生時，會伴隨許多副作用

Macrophages first try to fight off the infection, but they can become overwhelmed, triggering the release of cytokines.

巨噬細胞首先會試圖抵抗感染，但可能變得不堪負荷，引發細胞介質的釋放

These cytokines lead to inflammation of the lungs, causing air sacs called alveoli to fill with fluid.

這些細胞介質會導致肺部發炎，引發肺泡的氣囊充滿液體。

Yeah.

沒錯

So alveoli are air sacs in the lungs that are where the exchange of oxygen and carbon dioxide take place.

肺泡是肺部的氣囊，是氧氣和二氧化碳交換的地方。

And it's these alveoli that get filled with the fluid that's come from your bloodstream.

這些肺泡充滿來自血液的液體

Now, there's no particular reason for red cells to get out of the bloodstream but white

現在，沒有特別的理由讓紅血球離開血液

cells that are included in the bloodstream are very potent cells able to kill bacteria

但血液中的白血球是殺死細菌的強力細胞

and they move in from the bloodstream out into the tissues at the site of infection.

它們從血液流入感染部位的組織

But, filling the alveoli with fluid does more than just fight off the infection.

但肺泡裝滿液體不只可以抵抗感染

That's because, basically, your lung sacs are filling with pus.

那是因為，基本上你的肺裝滿了膿

The lungs are there and exquisitely designed for oxygen to pass from the air into your

肺那裡的巧妙設計讓氧氣從空氣

bloodstream...And so unfortunately, instead of having nice, clear air pockets where this

進入血液。而且不幸的是，如果它們充滿液體，

exchange can take place, if they're filled with fluid, then the exchange of oxygen and

那交換氧氣和釋放出來的二氧化碳也會受到損害，

the release of carbon dioxide, which you breathe out, also is impaired.

而不會有良好、乾淨的氣囊

This causes difficulty breathing as well as a whole host of symptoms that vary greatly in severity.

這導致呼吸困難，以及嚴重程度差異很大的一系列症狀。

The effects of walking or atypical pneumonia can be so mild, someone might not know even know they have it.

會行走的肺炎或非典型肺炎，其影響可能很輕微，可能甚至不知道已經患有了

In other cases, the infection can lead to death.

在其他病例中，這種感染可以導致死亡

But, while pneumonia is still a disease that kills millions of people worldwide, there

但是，雖然肺炎這種疾病在全球殺了百萬人

isn't a good reason why it should still be so lethal.

現在卻沒有充分的理由，說明其致命的的原因

The main driver of mortality from pneumonia, is access to treatment or lack thereof.

肺炎致死的主要因素是治療方法，或是說缺乏治療方法

So, in fact, there are vaccines that work to protect from both bacterial and viral pneumonias.

事實上，有些疫苗可以起到防止細菌和病毒性肺炎的作用。

In fact, the most successful vaccine for prevention of pneumonia is a bacterial vaccine.

其實，預防肺炎最成功的疫苗是細菌疫苗

So pneumonia deaths really shouldn't occur.

所以肺炎的死亡真的不該發生

It's preventable, as I mentioned, by vaccines, also treatable by antibiotics.

正如我所提到的，可以用疫苗預防，也可以用抗生素來治療

Because of this, pneumonia deaths are much more common in poorer countries with fewer resources.

因此，在資源較少的貧窮國家，肺炎的死亡更為常見。

Which is why Dr. Klugman is working on ways to develop more effective treatments in these areas of the world.

這也是為什麼 Klugman 醫生在為這些地區的人，努力開發出更有效的治療方法

But pneumonia deaths can still happen in places like the United States, especially if something

但肺炎死亡仍會發生在像美國這樣的地方，特別是

were to lead to people having compromised immune systems.

如果有什麼東西導致民眾的免疫系統受損

That could happen from contracting other illnesses, some of which are entirely preventable.

這可能從已感染的疾病中發生，而有些完全可以預防

So, as you know, there have been outbreaks of measles recently in the United States.

如你所知，最近美國爆發了麻疹

And globally, measles has not been eradicated.

還有在全球也是，代表麻疹還未完全根除

One of the major problems with measles is that it diminishes your immune response.

麻疹的主要一個問題是會減少你的免疫反應

And kids who have measles can get bacterial and viral pneumonias after their measles so,

患有麻疹的小孩在痊癒後，還可能得到細菌和病毒性肺炎

in fact, pneumonia is a major killer following measles exposure.

其實，肺炎是麻疹暴露後的主要殺手。

So a vaccine, there's a very potent vaccine for measles.

因此，麻疹有非常有效的一種疫苗

And measles prevention is a very important way of preventing deaths from pneumonia.

而預防肺炎死亡的重要方式就是預防麻疹