地球上最致命的病毒：英語精讀講義

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

在 1970 年代，歐洲的天空曾下過一場由數千個雞頭組成的「陣雨」，

making foxes and other wildlife confused and very happy.

這讓狐狸和其他野生動物既困惑又無比高興。

Why?

為什麼呢？

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

因為這些雞頭裡裝滿了疫苗，用來對抗人類已知最致命的病毒。

Since the 1930s,

自 1930 年代以來，

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

狂犬病疫情一直在歐洲野生動物族群中肆虐，

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

而人類希望一勞永逸地徹底消滅這種病毒。

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

狂犬病（Rabies）得名於古希臘狂暴之神莉莎（Lyssa），

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

它已經困擾了我們至少 4000 年。

It can turn animals into angry beasts

它能把動物變成憤怒的野獸，

and humans into zombies that fear water.

把人類變成極度恐水的殭屍。

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

但莉莎的迷人之處不僅在於其感染方式的離奇和致命，

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

還在於它極其擅長躲避我們的防禦機制。

Viruses exist on the edge between life and death, 慣用語

病毒存在於生與死的邊緣，

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

幾乎只是一些需要活細胞才能繁殖的遺傳指令。

The lyssavirus is simple even for a virus.

即便是對於病毒來說，狂犬病毒屬（Lyssavirus）也顯得非常簡單。

It has only five genes,

它只有五個基因，

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

也就是製造五種蛋白質的指令，但這就足以讓它解決複雜問題，

infect a mammal, avoid its immune system,

比如感染哺乳動物、避開免疫系統、

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

前往大腦、自我複製，以及感染新的宿主。

Let's see what happens if you get infected.

讓我們看看如果你被感染會發生什麼。

It all starts with a bite, 表達脈絡

一切都始於被咬傷，

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

最有可能是一隻唾液中攜帶數百萬個病毒的狗，

pushing them deep into the tissue.

把它們深深推入你的組織中。

The goal is your nerve cells, your neurons.

病毒的目標是你的神經細胞，即神經元。

They are living electrochemical wires transferring signals throughout your body

它們是活的電化學導線，在你的全身傳遞訊號，

and can stretch for up to 1.5 meters

最長可以延伸 1.5 公尺，

with their cellular machinery on one end

一端是它們的細胞機器，

and a terminal on the other.

另一端是終端。

The terminal is where cells talk to each other

終端是細胞間交流的地方，

by passing chemicals that convey information.

透過傳遞傳達資訊的化學物質來實現。

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

莉莎可能與這一過程至關重要的受體結合，

and slips inside the unsuspecting nerve cells.

並溜進毫無防備的神經細胞內。

Inside, the virus has to solve a big problem.

在細胞內部，病毒必須解決一個大問題。

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

它需要接觸到細胞機器來接管細胞並製造更多病毒，

and because neurons are pretty long,

但由於神經元相當長，

this can be far away.

這個距離可能會很遠。

There is a solution at hand, though. 慣用語

不過，現成的解決方案就在眼前。

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

細胞內部有微管，不僅能賦予其結構完整性，

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

還為一種專門的運輸系統提供了軌道。

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

動力蛋白是真正的分子馬達，消耗能量並運送包裹。

They're made from 50 different proteins,

它們由 50 種不同的蛋白質組成，

10 times more than the virus,

比這種病毒的蛋白種類多 10 倍，

and look like a little pair of shoes.

看起來像一雙小鞋子。

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

莉莎利用它的五種蛋白質之一來劫持這個神奇的系統，

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

並命令它向細胞核進發。

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

那免疫系統在做什麼來阻止這一切呢？

Well, unfortunately, not much.

好吧，不幸的是，沒做什麼。

Usually, when a virus attacks,

通常，當病毒入侵時，

your civilian cells are crucial in activating your immune response.

你的一般細胞在活化免疫反應中起著關鍵作用。

They notice that they've been infected

它們注意到自己被感染了，

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

並釋放出數十萬個屬於特殊蛋白質家族的蛋白質，

the interferons that,

也就是干擾素，顧名思義，

well, interfere with viruses.

它們用來干擾病毒。

We'll have to simplify a lot,

我們必須大幅簡化這個過程，

but in a nutshell, 慣用語

但簡而言之，

interferons alert your immune system to make antivirus weapons.

干擾素會警告你的免疫系統去製造抗病毒武器。

But they do much more.

但它們做的遠不止這些。

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

它們告訴一般細胞暫時降低蛋白質工廠的產量，

which means that viruses can't replicate efficiently anymore.

這意味著病毒無法再高效複製。

And interferons tell your cells to become super transparent,

干擾素還告訴你的細胞變得極其透明，

which is important

這很重要，

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

因為如果病毒藏在一般細胞裡面，

when viruses hide inside them?

你的免疫細胞怎麼能注意到它們被感染了呢？

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

你的身體透過在它們表面創建展示櫥窗來解決這個問題，

called MHC class 1 molecules.

這被稱為 MHC 第一型分子。

Cells constantly produce stuff to stay alive,

細胞不斷生產物質以維持生命，

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

為了向免疫細胞展示它們內部正在發生什麼，

they take random samples of their products

它們會隨機抽取其產品的樣本，

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

並放進這些小展示櫥窗裡，讓外界能夠一窺究竟。

Interferons tell your cells to make way more display windows

干擾素告訴你的細胞製造更多的展示櫥窗，

and become super transparent.

並變得極其透明。

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

如果一個細胞被感染並被迫製造病毒部件，

your immune cells will see these parts in a window

你的免疫細胞會在櫥窗裡看到這些部件，

and order the infected cell to kill itself

並命令受感染的細胞自殺，

and all the viruses trapped within.

連同困在裡面的所有病毒一起消滅。

This is one of the most powerful methods

這是最強大的方法之一，

of wiping out a viral infection. 片語動詞

用來消滅病毒感染。

Unfortunately,

不幸的是，

Lyssa blocks your neurons from making interferons 文法

莉莎阻止了你的神經元製造干擾素，

and stays basically invisible to your immune system.

並基本上對你的免疫系統保持隱身。

In contrast to many other viruses, 表達脈絡

與許多其他病毒相反，

when it replicates,

當它複製時，

it doesn't kill its host,

它不會殺死它的宿主，

which would also trigger alarm systems.

因為那同樣會觸發警報系統。

Instead,

相反，

it stealthily jumps from neuron to neuron,

它悄無聲息地從一個神經元跳到另一個神經元，

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

非常緩慢地向你的大腦進發。

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

這個階段可能需要幾週到幾個月，極少數情況下甚至幾年，

and depends on a bunch of things,

這取決於許多因素，

like if the bite was in your face or foot,

比如咬傷是在臉上還是腳上，

or how many viruses got into your muscles.

或者有多少病毒進入了你的肌肉。

Lyssa is a patient monster

莉莎是一個耐心的怪物，

until it reaches its goal,

直到它到達最終目的地，

your brainstem.

你的腦幹。

Finally,

終於，

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

免疫系統察覺到了不對勁，

and reacts.

並做出反應。

It dispatches some of your most powerful antivirus cells,

它派出一些最強大的抗病毒細胞，

killer T cells,

殺手 T 細胞，

to seek and kill infected cells

去尋找並殺死受感染的細胞，

and wipe out the enemy.

消滅敵人。

In other viral infections,

在其他病毒感染中，

this would be a turning point, 慣用語

這將是一個轉折點，

but in rabies,

但在狂犬病中，

the T cells are rushing towards their doom. 慣用語

T 細胞正在衝向它們的末日。

Simple Lyssa with its five proteins

簡單的莉莎僅僅帶著五種蛋白質，

plays a Uno reverse card, 文化背景

卻打出了一張 Uno 反轉卡，

using the immune system's ingenuity against itself.

利用免疫系統自身的機制來反擊它自己。

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

中樞神經系統是你身體中非常脆弱的部分，

and so the immune system has to be very careful.

所以免疫系統必須非常小心。

A few haywire immune cells in your brain 用詞

大腦中少數幾個失控的免疫細胞

is a quick way to die.

就能讓你快速死亡。

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

所以它們不能自由進入你的神經系統。

They have to be invited in 慣用語

它們必須被邀請進來，

and can be kicked out.

並且隨時可以被踢出去。

To protect themselves,

為了保護自己，

your nerve cells can order T cells

你的神經細胞可以命令 T 細胞

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

自毀，如果神經細胞覺得它們反應過度。

And Lyssa figured out a way

而莉莎想出了一個辦法，

to make infected neurons express this order.

讓受感染的神經元表達這個指令。

So as your powerful defense cells arrive,

所以當你強大的防禦細胞到達時，

they are ordered to commit suicide.

它們會被命令自殺。

Now, the virus infiltrates the brainstem.

現在，病毒滲透進了腦幹。

Once this stage is reached, 文法

一旦到達這個階段，

you are going to die.

你將必死無疑。

How Lyssa kills.

莉莎是如何殺人的。

One of the most irritating things about the Lyssavirus 文法

關於狂犬病毒，最令人氣惱的事情之一

is that we still don't know exactly

是我們仍然不完全清楚

how and why an infected person dies.

感染者究竟是如何以及為什麼死亡的。

Our usual idea of viruses causing damage

我們通常認為病毒造成損害的方式

is by multiplying rapidly,

是透過快速繁殖，

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

一旦製造出足夠多的副本就殺死宿主細胞，

triggering a massive immune reaction

引發大規模的免疫反應，

that also does a lot of damage.

這也會造成很大的損害。

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

但這似乎不是狂犬病的情況。

Brain tissue of rabies patients

狂犬病患者的腦組織

shows minimal,

顯示出極少，

sometimes non-existent damage.

有時甚至不存在的物理損傷。

Instead of murdering everything in sight, 講解

目前認為，莉莎不是謀殺眼前的一切，

it's currently thought that Lyssa wreaks havoc 慣用語

而是透過肆虐破壞

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

你大腦內部神經元之間的通訊，

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

嚴重到它無法再正常運作。

This leads to symptoms

這導致了各種症狀，

like confusion, aggression, and paralysis.

比如混亂、攻擊性和癱瘓。

Now, the virus begins to leave.

現在，病毒開始離開。

Still traveling through neurons,

它仍然透過神經元移動，

it migrates away from the brain

遠離大腦，

and heads for the salivary glands.

前往唾液腺。

This is remarkable

這是令人驚奇的，

because after traveling in one direction,

因為在朝一個方向行進後，

the virus reverses its course. 片語搭配

病毒竟然逆轉了它的路線。

After decades of study,

經過幾十年的研究，

we don't know how this works.

我們仍不知道這是如何發生的。

Lyssa ends up saturating your saliva, 片語動詞

最終，莉莎浸滿了你的唾液，

ready for the irate mammal 文法

準備好讓這隻暴怒的哺乳動物

to bite another

去咬下一隻，

and repeat the cycle.

重複這個循環。

While this seems like the beginning of a zombie outbreak,

雖然這看起來像是殭屍爆發的開端，

luckily,

幸運的是，

there are no known cases of a human

目前還沒有已知的人類

biting another

咬傷他人

and spreading rabies this way.

並以此方式傳播狂犬病的案例。

Now, the end is near.

現在，終點臨近了。

You are rapidly developing encephalitis,

你正在迅速患上腦炎，

a swelling of the brain

即大腦的腫脹，

with many unpleasant neurological symptoms

伴隨著許多令人痛苦的神經系統症狀，

from lethargy to paralysis.

從嗜睡到癱瘓。

Slowly at first and then suddenly, 表達脈絡

起初很慢，然後突然間，

organ after organ fails 文法

器官一個個衰竭，

as you slip into a coma. 片語搭配

你逐漸陷入昏迷。

There is no known effective therapy.

目前沒有已知有效的治療方法。

Barely anyone has ever survived Lyssa 文法

一旦症狀開始出現，

once symptoms begin to show.

幾乎沒有人能在莉莎的手下生還。

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

它是迄今為止我們所知最致命的病毒。

Except, 表達脈絡

除了一點，

there is actually something that could save you,

其實有一種東西可以救你，

a vaccine.

那就是疫苗。

Rabies was one of the first diseases

狂犬病是人類最早

humans developed a vaccine for.

開發出疫苗的疾病之一。

As vaccines do,

正如疫苗的作用機制，

it prepares your immune system

它讓你的免疫系統做好準備，

for a future attack,

以應對未來的攻擊，

so it has the right weapons ready

因此它準備好了正確的武器，

in high numbers.

且數量龐大。

The horrific tricks of simple Lyssa

一旦你接種了疫苗，

don't work once you are vaccinated. 文法

簡單的莉莎那些可怕的把戲就不起作用了。

And the vaccine is special for another reason,

而且這種疫苗還有另一個特別之處，

because Lyssa is so slow

因為莉莎的速度太慢了，

in the first few weeks,

在最初幾週裡，

it can be given to you

你可以在暴露後

after you've been exposed. 用詞

進行接種。

So you can still be vaccinated

所以即使你在被動物咬傷後

after you've been bitten by an animal,

仍然可以接種疫苗，

which is super important

這至關重要，

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

尤其是如果你接觸過生病的野生動物，

say a bat, 表達脈絡

比如蝙蝠，

because you often don't even notice

因為你往往甚至不會注意到

a bite from tiny teeth.

那些細小牙齒留下的咬傷。

Rabies is a monster,

狂犬病是個怪物，

one that has followed our species

它跟隨我們的人類物種

around for thousands of years,

幾千年了，

that our ancestors were terrified of,

我們的祖先對它充滿恐懼，

and rightly so. 片語搭配

這確實是有道理的。

It still kills around 60,000 people each year,

它每年仍然導致約 6 萬人死亡，

almost half of them children.

其中幾乎一半是兒童。

We are far from eradicating this monster. 片語搭配

我們遠未徹底消滅這個怪物。

It lurks in the shadows, 慣用語

它潛伏在陰影中，

in forests and animals of all kinds,

在森林裡和各種動物身上，

ready to return in greater numbers

隨時準備以更大的規模捲土重來，

if we ever forget

如果我們忘記了

how to keep it at bay 慣用語

如何將它拒之門外，

or if we continue the trend

或者如果我們繼續這種

of being suspicious of vaccines.

對疫苗持懷疑態度的趨勢。

Let's hope that one day

讓我們希望有一天

humanity slays this monster, 表達脈絡

人類能斬殺這個怪物，

so it can become,

這樣它就可以，

like most monsters,

像大多數怪物一樣，

part of our imagination.

成為我們想像中的一部分。