The deadliest animal on the planet responsible for the death of billions -

造成死亡數千億死亡， 是這個星球上最致命的動物

- the mighty mosquito.

即強大的蚊子 除了作為其他疾病的宿主外

Along with other diseases, it plays host to malaria,

它也是 "瘧疾" 地球上最瘋狂的寄生蟲之一的宿主

one of the cruelest parasites on earth,

可能是人類歷史上，最大的殺手之一。

possibly the single biggest killer of humans in history.

僅在2015年

In 2015 alone, hundreds of millions were infected.

就有數以億計的感染， 且造成約五十萬人死亡。

Almost half a million people died.

一項新技術可以幫助我們 根除瘧疾，

A new technology could help us eradicate malaria for ever.

但這樣做，我們需要修改整個動物種群。

But to do so, we need to engineer a whole animal population.

這不是一個假設問題， 基因改造的蚊子已存在於實驗室中。

This is not a hypothetical problem,

我們應該使用這項技術嗎？ 且瘧疾是否夠壞到讓我們願意冒這個風險呢？

The modified mosquitoes already exist in a lab.

(開頭音樂)

Should we use the technology, and is malaria bad enough to risk it?

瘧疾是由一種微生物所引起：瘧原蟲

[THEME MUSIC]

一種非常怪異的單細胞微生物，

Malaria is caused by a group of micro-organisms.

它們是完全依靠蚊子的寄生蟲 而瘧疾總是從叮咬開始的。

Plasmodia.

在蚊子的唾液腺中，有成千上萬的孢子 正等待著藉由蚊子叮咬穿透你的皮膚，

Very weird micro-organisms, that consist of just a single cell.

並在入侵後立即前往你的肝臟，

They're parasites that completely rely on mosquitoes.

在那裡他們悄悄地進入大細胞中， 並躲過免疫系統的偵查。

Malaria always starts with an insect bite.

他們會停留在該處長達一個月，不斷消耗活著的細胞，

In its salivary glands, thousands of sporozoites wait until the insect penetrates your skin.

並轉變為他們的下一個型態：像水滴般裂殖體

Immediately after invading you, they head for the liver,

它們不斷增殖，產生數千計的個體

where they quietly enter big cells and hide from the immune system.

然後迸發出細胞。

For up to a month, they stay here, in stealth mode, consuming the cells alive and changing into their next form -

因此，成千上萬的寄生蟲進入血液中

small, drop-like merozoites.

去尋找他們下一個受害者 - 紅血球。 為了不被注意，他們將自己包裹在

They multiply, generating thousands of themselves,

被他們殺死的細胞的細胞膜中，

and then burst out of the cells.

想像一下！

So thousands of parasites head into the bloodstream to look for their next victims -

從內而外殺死他人， 然後以他們的皮膚作為偽裝，殘酷！

Red blood cells.

它們現在猛烈攻擊紅血球， 在他們裡面不斷繁殖直到他們爆裂

To stay unnoticed, they wrap themselves in the membranes of the cells they killed.

然後尋找更多的紅血球， 且這個循環重複一遍又一遍。

Imagine that,

大量的死細胞形成大量的有毒廢料 其會造成強大的免疫反應

killing someone from the inside,

造成類似流感的症狀，

and then taking their skin as camouflage.

像是高燒、出汗和發冷、 抽搐、頭痛，有時嘔吐和腹瀉。

Brutal.

如果瘧疾穿過了血腦屏障 它可能會導致昏迷、神經損傷或死亡。

They now violently attack red blood cells,

而現在，寄生蟲現在準備要撤離了。

Multiplying inside them until they burst, then finding more red blood cells.

當另一個蚊子叮咬被感染的人， 他們就搭上順風車了，

This cycle repeats over and over

此一循環又可重新開始。

Pieces of dead cells spread lots of toxic waste material,

在2015年，會導致胎兒 可怕的先天缺陷的茲卡病毒

which activates a powerful immune response causing flu-like symptoms.

迅速蔓延到全球各地的新區域。

Among the symptoms are high fever, sweats and chills,

它也是由蚊子所傳遞的。

convulsions, headaches and sometimes vomiting and diarrhea.

蚊子是人類疾病的理想傳遞者

If malaria reaches the blood-brain barrier, it can cause coma, neurological damage, or death.

他們已經存在了至少2億年 除了他們有萬億隻外

The parasites are ready for evacuation now.

一個體一次可以產下高達300個卵 他們實際上是不可能被根除的

When another mosquito bites the infected human, they get a ride.

且是完美的寄生蟲計程車。

The cycle can start over.

但是今日，我們有一個新的革命性的技術， 將使我們能夠最終贏得戰爭

In 2015, the Zika virus,

CRISPR (常間回文重複序列叢集) 在人類歷史上第一次，我們有工具進行

which causes horrible birth defects if it infects pregnant women,

快速，大規模改變整個物種， 依照我們的喜好改變他們的遺傳信息

spread rapidly into new areas around the globe.

所以與其攻擊孤立的昆蟲群體，

It too is carried by a mosquito.

為什麼不改變傳播疾病的媒介？

The mosquito is the perfect carrier for human diseases ,

利用基因工程，科學家

They've been around for at least 200 million years,

成功創建 免疫瘧疾寄生蟲的蚊子品系

there are trillions of them,

通過增加專門針對瘧原蟲新的抗體基因

and a single one can lay up to 300 eggs at a time.

這些蚊子永遠不會傳播瘧疾 但只是改變遺傳信息是不夠的

They are practically impossible to eradicate,

該修改會將僅由半數的後代繼承

and the perfect parasite taxi.

因為大多數基因具有 兩個基因組版本作為失效保護

But today, we have new revolutionary technology

所以在兩個世代後， 最多只有一半的後代會帶有修改的基因。

that could enable us to finally win the war against them.

因此在數十億蚊子的種群中，

CRISPR.

他們將很難有所作為。

For the first time in human history,

一種被稱為基因驅動的 基因工程方法解決了這個問題

we have the tools to make fast, large-scale changes to entire species,

他會強迫新加入的基因成為顯性 並在接下來的世代中

changing their genetic information as we please.

幾乎完全地複寫掉舊的基因

So, instead of attacking isolated groups of insects,

受益於這個方法，99.5% 的基因修改蚊的後代 會帶有抗瘧疾的基因。

why not just change the types that transmit diseases?

如果我們釋放出足夠的改造的蚊子 到野外與普通蚊子交配，

Using genetic engineering,

抗瘧疾的基因將會擴散的十分快速

Scientists successfully created a strain of mosquitos that are immune to the malaria parasite,

由於新的基因成為蚊子群集的永久特徵，

by adding a new antibody gene that specifically targets plasmodium.

瘧原蟲就會失去它的大本營。

These mosquitoes will never spread malaria.

科學家希望這種變化能足夠迅速， 以至於它們無法改變的夠快去適應它

But just changing genetic information is not enough.

瘧疾就可能就會幾乎消失。

The edits would only be inherited by half the offspring,

如果考慮到每年有約50萬兒童因它死亡，

because most genes have two versions inside the genome as a fail- safe.

則從本影片開始至此已有大約五名孩童死亡。

So after just two generations, at most only half of the offspring would carry the engineered gene.

一些科學家認為，我們應該盡早用該技術 而不是更晚才開始。

In a population of billions of mosquitoes,

此外蚊子自己大概也會從此獲得好處，

They would hardly make a difference

畢竟攜帶寄生蟲對牠們也沒有助益。

A genetic engineering method called the gene drive solves this problem.

而且這也許只是第一步，

It forces the new gene to become dominant in the following generations,

瘧疾可能只是個開始。

overpowering the old gene almost completely.

不同的蚊子還攜帶登革熱和茲卡病毒、

Thanks to this twist, 99.5% of all the engineered mosquitoes' offspring will carry the anti-malaria edit.

蜱傳播萊姆病、蒼蠅傳播昏睡病、

If we were to release enough engineered mosquitoes into the wild to mate with normal mosquitoes,

病蚤傳播鼠疫。 我們可以挽救數百萬人的生命，

The malaria-blocking genes would spread extremely quickly.

並防止在一個令人難以置信的規模上的苦難

As the new gene becomes a permanent feature of the mosquito population,

那麼，為什麼我們還沒這樣做呢？

plasmodium would lose its home base.

首先，CRISPR 編輯

Scientists hope that the change would be so fast, they could not adapt to it quickly enough.

才誕生4年左右，所以直到最近， 我們還不能將其做的足夠快速和容易。

Malaria could virtually disappear.

而且這必須有合理的關切。

If you take into account that almost half a million children are killed by it every year,

歷史上從未有過，人類有意識地， 在如此巨大規模下，改變自由生活的生物體的遺傳訊息

about five have died since this video started.

一旦我們這麼做，

Some scientists argue that we should use the technology sooner, rather than later.

就沒有回頭路。所以它必須被做對，

The mosquitoes themselves would probably only profit from this.

因為編輯大自然，可能造成不良的後果

They don't have anything to gain from carrying parasites.

雖然，在瘧疾這種特殊情況下， 風險也許是可以接受

And this might only be the first step - malaria might just be the beginning.

因為遺傳修飾不會對整個基因組 產生大的變化。

Different mosquitoes also carry Dengue fever and Zika

它只是改變了一個非常特殊的一部分。

Ticks transmit lyme disease,

而在這裡的最壞的情況是

Flies transmit sleeping sickness,

它可能不管用或是 寄生蟲以更糟的方式適應。

Fleas transmit the plague.

這裡還有許多的爭論。

We could save millions of lives, and prevent suffering on an unbelievable scale.

像基因驅動一樣強大的技術，需要被小心關切處理，

So,why haven't we done this yet?

但在某些時候，我們必須自問：

For one, CRISPR editing is barely four years old,

那是否是不道德的， 當不使用這種技術時，每天將有1000兒童死亡。

so until very recently, we just couldn't do it as fast and easily.

人類必須決定在未來幾年內該如何行動。

And there are valid concerns.

而在此例中，此項技術極度需要公眾討論

Never before have humans consciously changed the genetic code of a free-living organism on this scale.

你有什麼想法？

Once we do it, there is no going back.

該影片 由Patreon上觀眾的捐款而成為可能。 如果您想幫助我們

So it has to be done right,

做出更多像是這個影片的影片 並獲得不錯的獎勵作為回報，

because there could be unwanted consequences if we set out to edit nature

你可以在這裡這麼做。 我們真的很感激。

In the specific case of malaria though,

如果你想了解更多關於基因工程的話題 我們有另外一些關於CRISPR和基改生物的影片，

the risk might be acceptable since the genetic modification doesn't make a big change in the overall genome,

而如果這對你太生物了， 這裡是一個有關太空的播放列表。

It only changes a very specific part.

The worst case scenario here, is probably that it might not work,

or that the parasite adapts in a negative way.

There is still much debate,

Technology as powerful as gene drive needs to be handled with a lot of care.

But at some point, we have to ask ourselves,

Is it unethical to not use this technology,

when everyday, one thousand children die?

Humanity has to decide how to act on this in the next few years.

The public discussion is way behind the technology in this case,

What do you think?

This video was made possible in part by viewer donations on patreon.

If you want to help us make more videos like this and get nice rewards in return,

you can do so here.

We really appreciate it.

If you want to learn more about the topic of genetic engineering,

we have another video about CRISPR and GMO's.

And in case that's too much biology for you, here's a space playlist.