Why is pneumonia so dangerous? - Eve Gaus and Vanessa Ruiz

翻译人员: Sherry Zhao 校对人员: Yolanda Zhang

Every time you breathe in, air travels down the trachea,

每次当你呼吸时， 空气将进入气管，

through a series of channels called bronchi,

经过一些名为支气管的通道，

and finally reaches little clusters of air sacs called alveoli.

最后到达一些小的气囊团， 叫做肺泡。

There are some 600 million alveoli in the lungs,

肺里有将近 6 亿个肺泡，

adding up to a surface area of roughly 75 square meters—

总面积大约为 75 平方米——

the size of a tennis court.

面积和一个网球场差不多大。

These tiny sacs, only one cell thick, facilitate a crucial exchange:

这些只有一个细胞厚的小气囊 促成了一项非常关键的转换：

allowing oxygen from the air we breathe into the bloodstream

使氧气能成功的进入到血管里，

and clearing out carbon dioxide.

并清理掉二氧化碳。

Pneumonia wreaks havoc on this exchange.

肺炎破坏了这个环节。

Pneumonia is an infection of the alveoli that causes them to fill with fluid.

肺炎是一种肺泡感染， 会导致肺泡充满液体。

There are many different kinds of pathogens that can cause pneumonia.

肺炎可以有许多不同的病因。

The most common ones are viruses or bacteria.

最常见的是病毒或病菌。

These microscopic invaders enter the body via droplets either in the air we breathe,

这些微小的入侵者要么是通过 吸入的空气中的水气，

or when we touch our eyes, noses,

要么是在我们碰过被感染的平面后，

or mouths after touching a contaminated surface.

又接触了我们的眼睛、 鼻子，或嘴而进入我们体内。

Then, they face the respiratory tract’s first line defense:

然后它们会面对 呼吸道的第一道防线：

the mucociliary escalator.

粘膜纤毛自动扶梯 （mucociliary escalator）。

The mucociliary escalator consists of mucus that traps invaders and tiny hairs

粘膜纤毛自动扶梯由困住入侵者的 粘液和一些细小的毛发组成，

called cilia that carry the mucus toward the mouth, where it can be coughed out.

这些毛发叫做纤毛，负责把粘液运送至 嘴巴，使它们可以被咳出去。

But some of these invaders may get past the mucociliary escalator

但是有些入侵者有可能 通过粘膜纤毛自动扶梯

into the lungs, where they meet the alveoli.

并进入到肺里，并接触到肺泡。

Because alveoli serve as critical exchange points

因为肺泡相当于血液和 来自体外的空气之间的

between the blood and air from the outside world,

一个临界交换点，

they have their own specialized types of white blood cells, or macrophages,

它们拥有专门的白血细胞， 又名巨噬细胞，

which defend against foreign organisms by enveloping and eating them.

这种细胞通过包络和 吞噬外来细胞来进行防御。

When pathogens enter the lungs, the macrophages work to destroy them.

当病因抵达肺部时， 巨噬细胞就会开始摧毁它们。

The immune system releases additional white blood cells in the alveoli to help.

免疫系统也会在肺泡中 释放出更多的白血细胞去帮忙。

As these immune cells fight the pathogens, they generate inflammation—

当免疫细胞和病因搏斗时， 它们会制造一些炎症——

and fluid as a by-product of the inflammation.

还有作为副产品的液体。

When this fluid builds up,

当这些液体积聚起来后，

it makes gas exchange inside the alveoli much more difficult.

就会使肺泡内的 空气转换更加困难。

As the level of carbon dioxide in the bloodstream begins to rise,

当血液里的二氧化碳含量增加时，

the body breathes more quickly to try to clear it out and get more oxygen in.

身体会更快的呼吸， 试图把它们清除掉并且吸进更多氧气。

This rapid breathing is one of the most common symptoms of pneumonia.

急促的呼吸是肺炎的 一种很常见的现象。

The body also tries to force the fluid out of the alveoli through coughing.

身体也试图通过咳嗽， 使那些液体脱离肺泡。

Determining the cause of pneumonia can be difficult,

确定肺炎的源头可能会有些困难，

but once it is established, doctors can prescribe antibiotics,

但是当它发生了， 医生就可以开抗生素，

which may include either antibacterial or antiviral treatments.

含有抗菌或抗病毒的治疗。

Treatment with antibiotics helps the body get the infection under control.

抗生素的治疗能够 使身体内的炎症得到控制。

As the pathogen is cleared out,

当病因清除以后，

the body gradually expels or absorbs fluid and dead cells.

身体会缓慢的驱逐或 吸收液体和死去的细胞残骸。

The worst symptoms typically fade out in about a week,

最极端的症状也会 在一星期内消失，

though full recovery may take as long as a month.

但是完全康复可能需要 长达一整个月。

Otherwise healthy adults can often manage pneumonia at home.

除此以外，健康的成年人 在家里就能够使肺炎得到控制。

But for some groups, pneumonia can be a lot more severe,

但是对一些群体来说， 肺炎的后果则要严重得多，

requiring hospitalization and oxygen, artificial ventilation,

当身体抗击炎症时， 需要住院治疗和氧气、

or other supportive measures while the body fights the infection.

人工呼吸机，或是其它辅助措施。

Smoking damages the cilia,

吸烟会对纤毛造成损伤，

making them less able to clear even the normal amount of mucus and secretions,

使他们难以清除 正常含量的粘液和分泌物，

let alone the increased volume associated with pneumonia.

更何况是由肺炎引起的超标含量。

Genetic and autoimmune disorders

遗传和自身免疫的毛病

can make someone more susceptible to pathogens that can cause pneumonia.

可以使一些人 更加容易感染肺炎。

Young children and the elderly also have impaired clearance

幼童和老年人肺部的 自我清除能力和免疫系统

and weaker immune systems.

都相对较弱。

And if someone has viral pneumonia,

当一个人患有肺炎时，

their risk of bacterial respiratory infection is higher.

它们患有细菌性 呼吸感染的风险也更高。

Many of the deaths from pneumonia are due to lack of access to healthcare.

许多因肺炎死亡的案例都是 由于没有很好的医疗条件导致的。

But sometimes, even with appropriate care,

但是有些时候， 即使有需要的设施和看护，

the body enters a sustained fight against the infection it can’t maintain,

当身体进入了一场自身无法承受的 对抗感染的持久战，

activating inflammatory pathways throughout the body,

就会激活身体各处的炎症途径，

not just in the lungs.

不只是在肺里。

This is actually a protective mechanism,

这其实是一个保护机制，

but after too long in this state organs start shutting down,

但是这个状态过久， 器官就会开始衰竭，

causing shock and sometimes death.

引发休克，甚至是死亡。

So how can we prevent pneumonia?

那么，我们要如何预防肺炎呢？

Eating well and getting enough sleep and exercise

正常饮食，充足的睡眠和运动

helps your body fight off infections.

能帮助你的身体战胜感染源。

Vaccines can protect against common pneumonia-causing pathogens,

疫苗可以对抗常见的肺炎病因，

while washing your hands regularly helps prevent the spread of these pathogens—

同时，勤洗手也可以 抑制这些病因的传播——

and protect those most vulnerable to severe pneumonia.

并保护那些对肺炎 没有抵抗能力的人。