Name: 世界で最も早く蔓延している病気を逆転させる (Reversing The World's Fastest Spreading Disease)
Uploaded: 2021-01-14T08:54:46.000Z
Duration: 11 min 6 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

程度の副詞

For half of the planet, mosquitoes are more than just a nuisance.

Their bites transmit parasites and viruses that kill millions of people each year.

One of them, dengue virus,  causes dengue fever.

because the patients feel like the bones  in their bodies are being broken.

If you get sick with dengue, you can have mild symptoms through to very extreme symptoms,

where you're going to have internal bleeding,

but if you speak to anybody that's had  a bad dose of dengue,

they'll tell you it's one of the worst things that happened to them in their life.

Dengue is considered the world’s fastest spreading tropical disease.

Its cases have risen thirtyfold in the last 50 years.

Dengue is like everywhere in the tropics.

Potentially 40% of the world's population is at risk this year of getting dengue.

And with the world’s temperatures rising,

dengue can spread out of the tropics potentially reaching a further two billion people by 2080.

In Indonesia the total number of dengue cases is second in the world.

It has been proven very difficult to sort of

get rid of all the mosquitoes causing dengue.

In the laboratories chemicals are discovered for killing mosquitoes.

We’ve tried very hard but still,  the mosquitoes are around us.

So it needs something else to combat dengue.

Eight years ago Scott O’Neill founded The World Mosquito Program,

a non-profit initiative running trials in 12 countries around the world,

In particular one mosquito, Aedes aegypti,

it is responsible for transmitting between people a number of diseases.

Some of them obscure, some of them quite famous.

So diseases like yellow fever, dengue, chikungunya, and most recently, Zika.

And the reason that this particular mosquito, Aedes aegypti, is so good

at being able to cause these explosive epidemics

is because it's like the cockroach of the mosquito world.

Just like cockroaches,  it likes to live with people.

It doesn't live out in the forest in harmony with nature or whatever,

it lives in people's houses, in concrete jungles, in cities,

and it bites people, maybe two or three times a day.

And so often whole families get sick with dengue,

because that one mosquito bit everybody in that house within a period of a couple of days.

As soon as people discovered  that mosquitoes transmit disease,

the immediate response is let's kill mosquitoes.

The thing is all those diseases are still pretty well here.

And the reason is that  mosquitoes are really tough to kill

and if you realize where they breed,  you know just in a tiny bit of water,

you realize that there are millions and millions of places where these mosquitoes are breeding

and a thought of killing  every single one of them

Most researchers have focused on genetically modifying mosquitoes,

or trying to eradicate the species entirely.

Instead, O’Neill’s team is infecting mosquitoes with bacteria - not to kill them,

It’s a naturally occurring bacterium called Wolbachia.

That bacterium spreads into the mosquito population,

and once the mosquitoes have it, they're unable to transmit the virus between people.

You know, I’ve had this obsession for a long time  of working on Wolbachia.

It occurs naturally in around 60 to 70% of all insect species all around the world so

wherever you live, if you were to go outside, grab some insects out of the nearest bush

you’d likely find, more often than not, that those insects

naturally have this bacteria called Wolbachia.

The mosquito though, that transmits all these viruses to people, doesn't have it.

When we were able to put the Wolbachia  into the mosquito

and then we fed those mosquitoes in a laboratory virus,

we found that just Wolbachia by itself,  without any fancy tricks,

would stop the transmission of the viruses.

Wolbachia was stopping, not just dengue, but yellow fever,

chikungunya, Zika, Mayaro, a whole range of viruses

to disease carrying mosquitoes like the Aedes aegypti isn’t easy.

In fact, the only way to do it is to inject freshly laid mosquito eggs with the bacterium.

O’Neill’s team has spent more than five years building their colony of a few thousand mosquitoes.

This bacterium transmits itself vertically from a mother to her offspring,

So what Wolbachia does is that if it's in a female it will be transmitted

and so that female can mate with either males that have Wolbachia, or males that don't

and she'll produce eggs, and those eggs  will all have Wolbachia.

If the male has Wolbachia, but the female doesn't have Wolbachia,

then she will lay eggs and all her eggs will die.

The end result of that is that only females that have Wolbachia are able to reproduce.

And so Wolbachia then spreads into the insect population without having to be infectious,

without having to jump from one individual to another.

In Yogyakarta, whenever you go to the community and you ask,

”Do you know anyone that had dengue before?”

my guess is that everyone will answer "Yes."

Because it's so common, and it's still created a panic within the community.

People often, who live in transmission areas, live with a lot of fear about dengue.

Actually it's a family of viruses.  It can be grouped into four groups.

And unimaginatively, they're called dengue 1, 2, 3, and 4.

When you get infected, say, with dengue 1, your body makes antibodies against dengue 1,

and so it's much harder for you to then acquire dengue 1 again, the second time.

But those antibodies don't protect you for dengue 2, 3, or 4.

But not only that, those antibodies will make it easier for dengue 2, 3, and 4

to get into your body and cause disease and actually create potentially more severe disease.

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世界で最も早く蔓延している病気を逆転させる (Reversing The World's Fastest Spreading Disease)

eliminate

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potentially

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