species transmit parasites and viruses -- like the ones that cause Malaria, Yellow Fever,

種類還會傳遞寄生蟲和病毒-- 像是瘧疾、黃熱病

and Zika -- infecting and killing hundreds of thousands of people each year.

還有茲卡病毒--每年有上百萬人感染喪命

And when we told you about the Zika virus a couple weeks ago, a lot of you had the same question:

兩個星期前我們談到茲卡病毒，很多人有同樣的疑問：

Why don’t we just kill them all? All of them! Kill all the mosquitoes!

為什麼不把蚊子殺光？全部殺掉！殺死蚊子！

Humans are historically really good at making things go extinct. So it shouldn’t be too

人類在歷史上真的很善於滅絕其他物種，所以

hard to get rid of these bloodsuckers… right?

擺脫這些吸血鬼應該不會太難... 對吧？

Yeah... not exactly.

欸... 不完全是

First of all, there are over 3,000 mosquito species worldwide, and only a couple hundred

首先，世界上有超過3000種蚊子，只有200多種

of them bite humans.

會咬人類

Mosquitoes have been around for a lot longer than people, millions of years, and have survived

蚊子存在的時間比人類還久，幾百萬年以來蚊子一直都在

lots of predators and environmental changes.

從掠食者和環境改變之中存活下來

So that would be a lot of tough insects to kill, and a lot of bug deaths that wouldn’t

所以如果要這麼做，不僅要殺掉一堆難纏的蟲子，還會殺死許多其實不會

affect humans at all.

影響人類的物種

And we’ve tried to eradicate mosquitoes before, mostly using chemicals that turned

我們先前也試過撲殺蚊子，大多是使用化學物質

out to be awful for both the planet and us, like DDT.

不過這對植物和人類都會造成不良影響，像是DDT

But let’s pretend that we were actually able to kill all the mosquitoes in some not-environmentally-apocalyptic

不過，我們先假裝自己能以對環境無害的方式殺死所有蚊子，

way. Say, if I wished on a star, and the next day all mosquitoes just poofed out of existence.

像是跟星星許願，然後隔天蚊子就再也消失無蹤

Would that be so bad for the Earth?

這樣就對地球無害了嗎？

Some scientists actually say no -- that if mosquitoes were suddenly ripped out of food

有些科學家的答案其實是否定的，假如蚊子突然從食物網消失

webs, most ecosystems would heal pretty quickly, and other organisms would fill in those gaps.

多數生態系統會迅速修復，會有其他有機體填補這個空缺

But other scientists argue that certain mosquito species do play important ecological roles.

但有些科學家認為，某些種類的蚊子在生態系中扮演重要角色

Take the mosquitoes that live in the Arctic of Canada and Russia.

就像活動於加拿大和俄國境內北極地區的蚊子

They fly around in gigantic thick swarms and make up a huge part of the biomass there. And these

這些蚊子集結成一大群飛動，在那裡形成為數不小的生物量

mosquitoes pollinate Arctic plants and are a major food source for migrating birds.

這些蚊子幫助北極植物授粉，並且是候鳥的主要食物來源

Removing these guys -- or other, more southern species that are food for fish, birds, and

把這些傢伙除掉－－或除掉其他種類，然而有更多南方的品種是魚類、鳥類和

other insects -- could send a ripple through ecosystems, endangering many other plants

其他昆蟲的食物，如此將在生態系中引發連鎖效應，危害其他植物

and animals.

和動物

So we probably shouldn’t kill all the mosquitoes.

所以，也許我們不該殺了所有蚊子

But, we also don’t have to. We know which species are vectors, or carriers, of the worst

不過，我們也不需這麼做，我們知道哪些品種是帶菌者或媒介，他們會傳播

viruses and parasites that can infect humans.

影響人類甚劇的病毒和寄生蟲

So lots of researchers are currently targeting these species, and developing ways to kill

所以許多研究人員目前正鎖定這些品種，研發出一些方法來殺死

them, or to kill the dangerous stuff inside them.

他們，或者摧毀他們體內最危險的部分

Take the genus Aedes, which transmits lots of awful diseases. One particularly nasty

舉豹腳蚊來說，豹腳蚊散布許多可怕的疾病，其中最惡名昭彰的

species is Aedes aegypti, which is the primary vector for the Yellow Fever, Dengue, Chikungunya,

品種是埃及斑蚊，它是黃熱病、登革熱、屈公病的主要帶原者，

and Zika viruses.

還有茲卡病毒

A. aegypti is not just a pest, it’s one of the most medically significant pests. So

埃及斑蚊不僅只是害蟲，也是醫學上最具意義的害蟲，所以

it’s the focus of lots of recent experiments in targeted mosquito eradication.

最近很多實驗的重點，都鎖定在消滅蚊子

But some of the most promising research doesn’t set out to kill mosquitoes outright -- instead,

但一些具威信的研究，並不完全著手於殺死蚊子-－而是在

it genetically modifies them.

改造蚊子的基因

In 2015, a British company called Oxitec created male A. aegypti mosquitoes with a self-limiting

2015年，英國公司Oxitec製造出有自限性基因的雄性埃及斑蚊

gene, which basically means that the gene can stop their cells from functioning normally.

意思是這種基因會讓細胞無法正常運作

When these genetically modified mosquitoes are released and mate with females in the

當這些基改蚊子被釋放出來，在野外和雌性交配後

wild, the self-limiting gene gets passed on to their offspring.

自限性基因會傳給他們後代子孫

Those offspring usually can’t develop properly and die before they become adults.

這些基改蚊子的後代通常無法正常發育，並在成蟲前死亡

No adult mosquitoes means no disease transmission.

沒有蚊子成蟲表示沒有疾病傳播

Likewise, a team of scientists in California inserted modified genes into a species of

同樣地，加州有一組科學家將基因改造後植入某種

Anopheles mosquitoes, which are vectors for the parasite that causes Malaria.

瘧蚊，瘧蚊是傳播瘧疾寄生蟲的帶原者

The modified genes cause the mosquitoes to kill the Malaria-causing parasites that live

基改蚊子會將體內導致瘧疾的的寄生蟲殺死

inside them, before they can transmit them to humans.

再開始傳播給人類前就殺死這些寄生蟲

And as a bonus, these parasite-destroying genes are designed to be passed on to 99.5%

另外，這些摧毀寄生蟲的基因被設計成可以99.5%傳給

of the mosquitoes’ offspring.

蚊子的下一代

So, eventually, this entire species could be unable to transmit Malaria. And scientists

所以，到最後，這整個品種的蚊子就無法傳播瘧疾，科學家

think that this same technology could be applied to other mosquito species, and other parasites

思考後覺得同樣的科技可以應用在其他品種的蚊子或是寄生蟲

and viruses -- like Zika.

還有病毒－像是茲卡

Lastly, some scientists are fighting fire with fire -- or fighting viruses with bacteria

最後，有些科學家則是以毒攻毒－－用細菌來打擊病毒

-- by intentionally infecting A. aegypti mosquitoes with a bacterium called Wolbachia.

－－讓埃及斑蚊感染一種叫Wolbachia的細菌

Wolbachia seems to stop most viruses from growing inside these mosquitoes. So even if

Wolbachia細菌似乎可以阻止病毒在蚊子體內成長，所以，即使

the mosquitoes bite people infected with, say, the Dengue virus, the virus wouldn’t

蚊子咬了被登革熱感染的人，病毒也不會

survive inside the mosquito long enough to be transmitted to a new person.

在蚊子體內存活太久，無法存活到傳播給下一個人

Now, because viruses mutate rapidly, scientists worry about accidentally creating deadly viruses

現在，因為病毒變化非常快速，科學家擔心會意外製造致命病毒

that are resistant to Wolbachia.

也就是可以抵抗Wolbachia的病毒

But a study released this week suggested a strategy to superinfect mosquitoes with more

但這週發表的一篇研究建議要盡量感染蚊子，並且

than one strain of the bacteria at a time.

一次要用不只一種細菌

This way, the viruses can’t develop resistance to the bacteria as easily. And we can keep

如此，病毒就無法輕易發展成可對抗某種細菌，我們就可以繼續

infecting mosquitoes, to keep them from infecting us.

感染蚊子，讓蚊子無法感染我們

I mean, it’s only fair.

我想，這很公平

So, basically, it would be incredibly difficult and possibly harmful to kill all the mosquitoes.

所以，基本上，要殺掉所有蚊子是非常困難的，也許還會造成危害

But we may soon be able to focus on certain species and take away their ability to infect

但我們能聚焦在某些品種，移除它們感染人類的能力

us, making the world a lot safer.

讓世界更安全

But... not any less itchy.

但是...沒辦法讓被咬比較不癢

Thanks for watching this episode of SciShow News.

感謝收看這一集 《科學秀新聞》

Thank you to all of the people doing this amazing research.

感謝進行這項超棒研究的大家

And thank you to our patrons on Patreon who support SciShow so it can always be freely

也感謝各位資助Patreon，《科學秀新聞》在Patreon的支持下，才能免費

available to everyone.

讓大家觀看

If you want to help us keep making shows like this, you can go to patreon.com/scishow­.

如果您想幫助我們製作更多類似的節目，請到 patreon.com/scishow­.

And if you just want to keep getting smarter with us, you ca go to youtube.com/scishow and subscribe!

想跟我們一起變聰明，請訂閱 youtube.com/scishow !