地球上最致命的病毒：英语精读讲义

In the 1970s, thousands of chicken heads rained from the sky in Europe, 表達脈絡

在 20 世纪 70 年代，欧洲的天空曾下过一场由数千个鸡头组成的“阵雨”，

making foxes and other wildlife confused and very happy.

这让狐狸和其他野生动物既困惑又无比高兴。

Why?

为什么呢？

They were filled with a vaccine to fight the deadliest virus known to humanity.

因为这些鸡头里装满了疫苗，用来对抗人类已知最致命的病毒。

Since the 1930s,

自 20 世纪 30 年代以来，

a rabies epidemic had been sweeping across wildlife populations in Europe 語法

狂犬病疫情一直在欧洲野生动物种群中肆虐，

and humans wanted to finally get rid of the virus once and for all. 講解

而人类希望一劳永逸地彻底消灭这种病毒。

Rabies is named after Lyssa, the ancient Greek spirit of mad rage, 短語搭配

狂犬病（Rabies）得名于古希腊狂暴之神莉莎（Lyssa），

and has been haunting us for at least 4,000 years. 習語

它已经困扰了我们至少 4000 年。

It can turn animals into angry beasts

它能把动物变成愤怒的野兽，

and humans into zombies that fear water.

把人类变成极度恐水的僵尸。

But what makes Lyssa fascinating is not just how bizarre and deadly its infection is, 語法

但莉莎的迷人之处不仅在于其感染方式的离奇和致命，

but also how incredibly good it is at avoiding our defenses.

还在于它极其擅长躲避我们的防御机制。

Viruses exist on the edge between life and death, 習語

病毒存在于生与死的边缘，

hardly more than a few genetic instructions that need living cells to multiply. 語法

几乎只是一些需要活细胞才能繁殖的遗传指令。

The lyssavirus is simple even for a virus.

即便是对于病毒来说，狂犬病毒属（Lyssavirus）也显得非常简单。

It has only five genes,

它只有五个基因，

that is the instructions for five proteins that let it solve complex problems,

也就是制造五种蛋白质的指令，但这就足以让它解决复杂问题，

infect a mammal, avoid its immune system,

比如感染哺乳动物、避开免疫系统、

travel to its brain, make more of itself, and infect new hosts. 短語搭配

前往大脑、自我复制，以及感染新的宿主。

Let's see what happens if you get infected.

让我们看看如果你被感染会发生什么。

It all starts with a bite, 表達脈絡

一切都始于被咬伤，

most likely by a dog carrying millions of viruses in its saliva,

最有可能是一只唾液中携带数百万个病毒的狗，

pushing them deep into the tissue.

把它们深深推入你的组织中。

The goal is your nerve cells, your neurons.

病毒的目标是你的神经细胞，即神经元。

They are living electrochemical wires transferring signals throughout your body

它们是活的电化学导线，在你的全身传递信号，

and can stretch for up to 1.5 meters

最长可以延伸 1.5 米，

with their cellular machinery on one end

一端是它们的细胞机器，

and a terminal on the other.

另一端是终端。

The terminal is where cells talk to each other

终端是细胞间交流的地方，

by passing chemicals that convey information.

通过传递传达信息的化学物质来实现。

Lyssa probably binds to the receptors that are crucial for this process

莉莎可能与这一过程至关重要的受体结合，

and slips inside the unsuspecting nerve cells.

并溜进毫无防备的神经细胞内。

Inside, the virus has to solve a big problem.

在细胞内部，病毒必须解决一个大问题。

It needs to get to the cellular machinery to take over the cell and make more viruses, 短語動詞

它需要接触到细胞机器来接管细胞并制造更多病毒，

and because neurons are pretty long,

但由于神经元相当长，

this can be far away.

这个距离可能会很远。

There is a solution at hand, though. 習語

不过，现成的解决方案就在眼前。

Cells have microtubules spanning their insides that give them structural integrity,

细胞内部有微管，不仅能赋予其结构完整性，

but they also provide a track system for a specialized delivery system.

还为一种专门的运输系统提供了轨道。

Dynein motors are actual motors that use energy and deliver packages.

动力蛋白是真正的分子马达，消耗能量并运送包裹。

They're made from 50 different proteins,

它们由 50 种不同的蛋白质组成，

10 times more than the virus,

比这种病毒的蛋白种类多 10 倍，

and look like a little pair of shoes.

看起来像一双小鞋子。

Lyssa uses one of its five proteins to hijack this amazing system 習語

莉莎利用它的五种蛋白质之一来劫持这个神奇的系统，

and order it to head for the nucleus. 短語搭配

并命令它向细胞核进发。

What's the immune system doing to prevent all of that? 表達脈絡

那免疫系统在做什么来阻止这一切呢？

Well, unfortunately, not much.

好吧，不幸的是，没做什么。

Usually, when a virus attacks,

通常，当病毒入侵时，

your civilian cells are crucial in activating your immune response.

你的平民细胞在激活免疫反应中起着关键作用。

They notice that they've been infected

它们注意到自己被感染了，

and release hundreds of thousands of a special family of proteins,

并释放数十万个属于一个特殊家族的蛋白质，

the interferons that,

也就是干扰素，顾名思义，

well, interfere with viruses.

它们用来干扰病毒。

We'll have to simplify a lot,

我们必须大幅简化这个过程，

but in a nutshell, 習語

但简而言之，

interferons alert your immune system to make antivirus weapons.

干扰素会警告你的免疫系统去制造抗病毒武器。

But they do much more.

但它们做的远不止这些。

They tell civilian cells to turn down their protein factories for a while, 講解

它们告诉平民细胞暂时降低蛋白质工厂的产量，

which means that viruses can't replicate efficiently anymore.

这意味着病毒无法再高效复制。

And interferons tell your cells to become super transparent,

干扰素还告诉你的细胞变得极其透明，

which is important

这很重要，

because how can your immune cells notice that your civilian cells are infected

因为如果病毒藏在平民细胞里面，

when viruses hide inside them?

你的免疫细胞怎么能注意到它们被感染了呢？

Your body solves this by creating display windows into their insides,

你的身体通过在它们表面创建展示橱窗来解决这个问题，

called MHC class 1 molecules.

这被称为 MHC I 类分子。

Cells constantly produce stuff to stay alive,

细胞不断生产物质以维持生命，

and to showcase to your immune cells what's going on inside them,

为了向免疫细胞展示它们内部正在发生什么，

they take random samples of their products

它们会随机抽取其产品的样本，

and put them into these tiny display windows to give a peek inside. 短語搭配

并放进这些小展示橱窗里，让外界能够一窥究竟。

Interferons tell your cells to make way more display windows

干扰素告诉你的细胞制造更多的展示橱窗，

and become super transparent.

并变得极其透明。

If a cell is infected and forced to make virus parts,

如果一个细胞被感染并被迫制造病毒部件，

your immune cells will see these parts in a window

你的免疫细胞会在橱窗里看到这些部件，

and order the infected cell to kill itself

并命令受感染的细胞自杀，

and all the viruses trapped within.

连同困在里面的所有病毒一起消灭。

This is one of the most powerful methods

这是最强大的方法之一，

of wiping out a viral infection. 短語動詞

用来消灭病毒感染。

Unfortunately,

不幸的是，

Lyssa blocks your neurons from making interferons 語法

莉莎阻止了你的神经元制造干扰素，

and stays basically invisible to your immune system.

并基本上对你的免疫系统保持隐身。

In contrast to many other viruses, 表達脈絡

与许多其他病毒相反，

when it replicates,

当它复制时，

it doesn't kill its host,

它不会杀死它的宿主，

which would also trigger alarm systems.

因为那同样会触发警报系统。

Instead,

相反，

it stealthily jumps from neuron to neuron,

它悄无声息地从一个神经元跳到另一个神经元，

very slowly making its way to your brain. 短語搭配

非常缓慢地向你的大脑进发。

This phase can take weeks to months and very rarely even years,

这个阶段可能需要几周到几个月，极少数情况下甚至几年，

and depends on a bunch of things,

这取决于许多因素，

like if the bite was in your face or foot,

比如咬伤是在脸上还是脚上，

or how many viruses got into your muscles.

或者有多少病毒进入了你的肌肉。

Lyssa is a patient monster

莉莎是一个耐心的怪物，

until it reaches its goal,

直到它到达最终目的地，

your brainstem.

你的脑干。

Finally,

终于，

the immune system catches on that something isn't right 講解

免疫系统察觉到了不对劲，

and reacts.

并做出反应。

It dispatches some of your most powerful antivirus cells,

它派出一些最强大的抗病毒细胞，

killer T cells,

杀手 T 细胞，

to seek and kill infected cells

去寻找并杀死受感染的细胞，

and wipe out the enemy.

消灭敌人。

In other viral infections,

在其他病毒感染中，

this would be a turning point, 習語

这将是一个转折点，

but in rabies,

但在狂犬病中，

the T cells are rushing towards their doom. 習語

T 细胞正在冲向它们的末日。

Simple Lyssa with its five proteins

简单的莉莎仅仅带着五种蛋白质，

plays a Uno reverse card, 文化背景

却打出了一张 Uno 反转卡，

using the immune system's ingenuity against itself.

利用免疫系统自身的机制来反击它自己。

Your central nervous system is a very fragile part of your body,

中枢神经系统是你身体中非常脆弱的部分，

and so the immune system has to be very careful.

所以免疫系统必须非常小心。

A few haywire immune cells in your brain 用詞

大脑中少数几个失控的免疫细胞

is a quick way to die.

就能让你快速死亡。

So they aren't free to enter your nervous system.

所以它们不能自由进入你的神经系统。

They have to be invited in 習語

它们必须被邀请进来，

and can be kicked out.

并且随时可以被踢出去。

To protect themselves,

为了保护自己，

your nerve cells can order T cells

你的神经细胞可以命令 T 细胞

to self-destruct if they think they're overreacting. 用詞

自毁，如果神经细胞觉得它们反应过度。

And Lyssa figured out a way

而莉莎想出了一个办法，

to make infected neurons express this order.

让受感染的神经元表达这个指令。

So as your powerful defense cells arrive,

所以当你强大的防御细胞到达时，

they are ordered to commit suicide.

它们会被命令自杀。

Now, the virus infiltrates the brainstem.

现在，病毒渗透进了脑干。

Once this stage is reached, 語法

一旦到达这个阶段，

you are going to die.

你将必死无疑。

How Lyssa kills.

莉莎是如何杀人的。

One of the most irritating things about the Lyssavirus 語法

关于狂犬病毒，最令人气恼的事情之一

is that we still don't know exactly

是我们仍然不完全清楚

how and why an infected person dies.

感染者究竟是如何以及为什么死亡的。

Our usual idea of viruses causing damage

我们通常认为病毒造成损害的方式

is by multiplying rapidly,

是通过快速繁殖，

killing their host cells once they've made enough copies,

一旦制造出足够多的副本就杀死宿主细胞，

triggering a massive immune reaction

引发大规模的免疫反应，

that also does a lot of damage.

这也会造成很大的损害。

But this doesn't seem to be what happens here.

但这似乎不是狂犬病的情况。

Brain tissue of rabies patients

狂犬病患者的脑组织

shows minimal,

显示出极少，

sometimes non-existent damage.

有时甚至不存在的物理损伤。

Instead of murdering everything in sight, 講解

目前认为，莉莎不是谋杀眼前的一切，

it's currently thought that Lyssa wreaks havoc 習語

而是通过肆虐破坏

by messing up the neuron communication inside your brain, 短語動詞

你大脑内部神经元之间的通讯，

so much so that it can't function anymore. 語法

严重到它无法再正常运作。

This leads to symptoms

这导致了各种症状，

like confusion, aggression, and paralysis.

比如混乱、攻击性和瘫痪。

Now, the virus begins to leave.

现在，病毒开始离开。

Still traveling through neurons,

它仍然通过神经元移动，

it migrates away from the brain

远离大脑，

and heads for the salivary glands.

前往唾液腺。

This is remarkable

这是令人惊奇的，

because after traveling in one direction,

因为在朝一个方向行进后，

the virus reverses its course. 短語搭配

病毒竟然逆转了它的路线。

After decades of study,

经过几十年的研究，

we don't know how this works.

我们仍不知道这是如何发生的。

Lyssa ends up saturating your saliva, 短語動詞

最终，莉莎浸满了你的唾液，

ready for the irate mammal 語法

准备好让这只暴怒的哺乳动物

to bite another

去咬下一只，

and repeat the cycle.

重复这个循环。

While this seems like the beginning of a zombie outbreak,

虽然这看起来像是僵尸爆发的开端，

luckily,

幸运的是，

there are no known cases of a human

目前还没有已知的人类

biting another

咬伤他人

and spreading rabies this way.

并以此方式传播狂犬病的案例。

Now, the end is near.

现在，终点临近了。

You are rapidly developing encephalitis,

你正在迅速患上脑炎，

a swelling of the brain

即大脑的肿胀，

with many unpleasant neurological symptoms

伴随着许多令人痛苦的神经系统症状，

from lethargy to paralysis.

从嗜睡到瘫痪。

Slowly at first and then suddenly, 表達脈絡

起初很慢，然后突然间，

organ after organ fails 語法

器官一个个衰竭，

as you slip into a coma. 短語搭配

同时，你也陷入昏迷。

There is no known effective therapy.

目前没有已知有效的治疗方法。

Barely anyone has ever survived Lyssa 語法

一旦症状开始出现，

once symptoms begin to show.

几乎没有人能在莉莎的手下生还。

It is by far the deadliest virus we know. 短語搭配

它是迄今为止我们所知最致命的病毒。

Except, 表達脈絡

除了一点，

there is actually something that could save you,

其实有一种东西可以救你，

a vaccine.

那就是疫苗。

Rabies was one of the first diseases

狂犬病是人类最早

humans developed a vaccine for.

开发出疫苗的疾病之一。

As vaccines do,

正如疫苗的作用机制，

it prepares your immune system

它让你的免疫系统做好准备，

for a future attack,

以应对未来的攻击，

so it has the right weapons ready

因此它准备好了正确的武器，

in high numbers.

且数量庞大。

The horrific tricks of simple Lyssa

一旦你接种了疫苗，

don't work once you are vaccinated. 語法

简单的莉莎那些可怕的把戏就不起作用了。

And the vaccine is special for another reason,

而且这种疫苗还有另一个特别之处，

because Lyssa is so slow

因为莉莎的速度太慢了，

in the first few weeks,

在最初几周里，

it can be given to you

你可以在暴露后

after you've been exposed. 用詞

进行接种。

So you can still be vaccinated

所以即使你在被动物咬伤后

after you've been bitten by an animal,

仍然可以接种疫苗，

which is super important

这至关重要，

if you've had contact with a sick wild animal, 短語搭配

尤其是如果你接触过生病的野生动物，

say a bat, 表達脈絡

比如蝙蝠，

because you often don't even notice

因为你往往甚至不会注意到

a bite from tiny teeth.

那些细小牙齿留下的咬伤。

Rabies is a monster,

狂犬病是个怪物，

one that has followed our species

它跟随我们的人类物种

around for thousands of years,

几千年了，

that our ancestors were terrified of,

我们的祖先对它充满恐惧，

and rightly so. 短語搭配

这确实是有道理的。

It still kills around 60,000 people each year,

它每年仍然导致约 6 万人死亡，

almost half of them children.

其中几乎一半是儿童。

We are far from eradicating this monster. 短語搭配

我们远未彻底消灭这个怪物。

It lurks in the shadows, 習語

它潜伏在阴影中，

in forests and animals of all kinds,

在森林里和各种动物身上，

ready to return in greater numbers

随时准备以更大的规模卷土重来，

if we ever forget

如果我们忘记了

how to keep it at bay 習語

如何将它拒之门外，

or if we continue the trend

或者如果我们继续这种

of being suspicious of vaccines.

对疫苗持怀疑态度的趋势。

Let's hope that one day

让我们希望有一天

humanity slays this monster, 表達脈絡

人类能斩杀这个怪物，

so it can become,

这样它就可以

like most monsters,

像大多数怪物一样，

part of our imagination.

成为我们想象中的一部分。