Re-engineering mosquitos to fight disease
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0:01 - 0:03So I'd like to start by focusing on
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0:03 - 0:06the world's most dangerous animal.
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0:06 - 0:08Now, when you talk about dangerous animals,
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0:08 - 0:11most people might think of lions or tigers or sharks.
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0:11 - 0:13But of course the most dangerous animal
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0:13 - 0:15is the mosquito.
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0:15 - 0:17The mosquito has killed more humans
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0:17 - 0:20than any other creature in human history.
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0:20 - 0:22In fact, probably adding them all together,
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0:22 - 0:24the mosquito has killed more humans.
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0:24 - 0:27And the mosquito has killed more humans than wars
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0:27 - 0:28and plague.
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0:28 - 0:31And you would think, would you not,
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0:31 - 0:35that with all our science, with all our advances in society,
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0:35 - 0:40with better towns, better civilizations, better sanitation,
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0:40 - 0:43wealth, that we would get better at controlling mosquitos,
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0:43 - 0:46and hence reduce this disease.
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0:46 - 0:49And that's not really the case.
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0:49 - 0:51If it was the case, we wouldn't have
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0:51 - 0:56between 200 and 300 million cases of malaria every year,
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0:56 - 0:57and we wouldn't have
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0:57 - 1:01a million and a half deaths from malaria,
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1:01 - 1:04and we wouldn't have a disease
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1:04 - 1:07that was relatively unknown 50 years ago
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1:07 - 1:09now suddenly turned into
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1:09 - 1:13the largest mosquito-borne virus threat that we have,
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1:13 - 1:15and that's called dengue fever.
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1:15 - 1:18So 50 years ago, pretty much no one had heard of it,
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1:18 - 1:21no one certainly in the European environment.
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1:21 - 1:25But dengue fever now, according to the World Health Organization,
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1:25 - 1:28infects between 50 and 100 million people every year,
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1:28 - 1:31so that's equivalent to the whole of the population
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1:31 - 1:34of the U.K. being infected every year.
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1:34 - 1:37Other estimates put that number at roughly double
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1:37 - 1:41that number of infections.
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1:41 - 1:45And dengue fever has grown in speed quite phenomenally.
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1:45 - 1:48In the last 50 years, the incidence of dengue
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1:48 - 1:50has grown thirtyfold.
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1:50 - 1:53Now let me tell you a little bit about what dengue fever is,
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1:53 - 1:54for those who don't know.
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1:54 - 1:57Now let's assume you go on holiday.
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1:57 - 1:58Let's assume you go to the Caribbean,
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1:58 - 2:01or you might go to Mexico. You might go to Latin America,
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2:01 - 2:05Asia, Africa, anywhere in Saudi Arabia.
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2:05 - 2:06You might go to India, the Far East.
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2:06 - 2:09It doesn't really matter. It's the same mosquito,
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2:09 - 2:12and it's the same disease. You're at risk.
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2:12 - 2:15And let's assume you're bitten by a mosquito
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2:15 - 2:16that's carrying that virus.
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2:16 - 2:19Well, you could develop flu-like symptoms.
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2:19 - 2:21They could be quite mild.
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2:21 - 2:23You could develop nausea, headache,
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2:23 - 2:25your muscles could feel like they're contracting,
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2:25 - 2:30and you could actually feel like your bones are breaking.
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2:30 - 2:32And that's the nickname given to this disease.
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2:32 - 2:33It's called breakbone fever,
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2:33 - 2:36because that's how you can feel.
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2:36 - 2:39Now the odd thing is, is that once you've been bitten
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2:39 - 2:41by this mosquito, and you've had this disease,
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2:41 - 2:44your body develops antibodies,
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2:44 - 2:48so if you're bitten again with that strain,
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2:48 - 2:50it doesn't affect you.
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2:50 - 2:53But it's not one virus, it's four,
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2:53 - 2:56and the same protection that gives you the antibodies
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2:56 - 2:59and protects you from the same virus that you had before
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2:59 - 3:02actually makes you much more susceptible to the other three.
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3:02 - 3:05So the next time you get dengue fever,
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3:05 - 3:07if it's a different strain, you're more susceptible,
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3:07 - 3:10you're likely to get worse symptoms,
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3:10 - 3:13and you're more likely to get the more severe forms,
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3:13 - 3:16hemorrhagic fever or shock syndrome.
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3:16 - 3:17So you don't want dengue once,
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3:17 - 3:20and you certainly don't want it again.
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3:20 - 3:23So why is it spreading so fast?
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3:23 - 3:25And the answer is this thing.
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3:25 - 3:27This is Aedes aegypti.
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3:27 - 3:30Now this is a mosquito that came, like its name suggests,
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3:30 - 3:34out of North Africa, and it's spread round the world.
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3:34 - 3:37Now, in fact, a single mosquito will only travel
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3:37 - 3:41about 200 yards in its entire life. They don't travel very far.
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3:41 - 3:43What they're very good at doing is hitchhiking,
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3:43 - 3:44particularly the eggs.
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3:44 - 3:49They will lay their eggs in clear water, any pool, any puddle,
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3:49 - 3:51any birdbath, any flower pot,
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3:51 - 3:54anywhere there's clear water, they'll lay their eggs,
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3:54 - 3:57and if that clear water is near freight, it's near a port,
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3:57 - 4:00if it's anywhere near transport,
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4:00 - 4:03those eggs will then get transported around the world.
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4:03 - 4:06And that's what's happened. Mankind has transported
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4:06 - 4:08these eggs all the way around the world,
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4:08 - 4:11and these insects have infested over 100 countries,
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4:11 - 4:14and there's now 2.5 billion people living in countries
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4:14 - 4:17where this mosquito resides.
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4:17 - 4:19To give you just a couple of examples
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4:19 - 4:21how fast this has happened,
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4:21 - 4:27in the mid-'70s, Brazil declared, "We have no Aedes aegypti,"
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4:27 - 4:29and currently they spend about a billion dollars now
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4:29 - 4:32a year trying to get rid of it, trying to control it,
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4:32 - 4:37just one species of mosquito.
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4:37 - 4:41Two days ago, or yesterday, I can't remember which,
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4:41 - 4:42I saw a Reuters report that said
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4:42 - 4:45Madeira had had their first cases of dengue,
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4:45 - 4:49about 52 cases, with about 400 probable cases.
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4:49 - 4:51That's two days ago.
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4:51 - 4:56Interestingly, Madeira first got the insect in 2005,
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4:56 - 4:58and here we are, a few years later,
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4:58 - 4:59first cases of dengue.
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4:59 - 5:03So the one thing you'll find is that where the mosquito goes,
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5:03 - 5:05dengue will follow.
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5:05 - 5:07Once you've got the mosquito in your area,
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5:07 - 5:10anyone coming into that area with dengue,
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5:10 - 5:12mosquito will bite them, mosquito will bite somewhere else,
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5:12 - 5:13somewhere else, somewhere else,
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5:13 - 5:18and you'll get an epidemic.
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5:18 - 5:19So we must be good at killing mosquitos.
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5:19 - 5:21I mean, that can't be very difficult.
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5:21 - 5:24Well, there's two principle ways.
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5:24 - 5:28The first way is that you use larvicides.
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5:28 - 5:30You use chemicals. You put them into water where they breed.
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5:30 - 5:33Now in an urban environment, that's extraordinarily difficult.
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5:33 - 5:35You've got to get your chemical into every puddle,
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5:35 - 5:38every birdbath, every tree trunk.
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5:38 - 5:41It's just not practical.
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5:41 - 5:42The second way you can do it
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5:42 - 5:45is actually trying to kill the insects as they fly around.
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5:45 - 5:48This is a picture of fogging.
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5:48 - 5:50Here what someone is doing
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5:50 - 5:53is mixing up chemical in a smoke
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5:53 - 5:56and basically spreading that through the environment.
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5:56 - 5:59You could do the same with a space spray.
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5:59 - 6:01This is really unpleasant stuff,
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6:01 - 6:03and if it was any good, we wouldn't have this massive increase
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6:03 - 6:08in mosquitos and we wouldn't have this massive increase in dengue fever.
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6:08 - 6:10So it's not very effective, but it's probably
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6:10 - 6:13the best thing we've got at the moment.
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6:13 - 6:15Having said that, actually, your best form of protection
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6:15 - 6:17and my best form of protection is a long-sleeve shirt
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6:17 - 6:21and a little bit of DEET to go with it.
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6:21 - 6:24So let's start again. Let's design a product,
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6:24 - 6:28right from the word go, and decide what we want.
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6:28 - 6:30Well we clearly need something that is effective
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6:30 - 6:32at reducing the mosquito population.
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6:32 - 6:35There's no point in just killing the odd mosquito here and there.
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6:35 - 6:38We want something that gets that population right the way down
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6:38 - 6:41so it can't get the disease transmission.
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6:41 - 6:44Clearly the product you've got has got to be safe to humans.
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6:44 - 6:46We are going to use it in and around humans.
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6:46 - 6:48It has to be safe.
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6:48 - 6:50We don't want to have a lasting impact on the environment.
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6:50 - 6:54We don't want to do anything that you can't undo.
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6:54 - 6:59Maybe a better product comes along in 20, 30 years.
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6:59 - 7:01Fine. We don't want a lasting environmental impact.
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7:01 - 7:05We want something that's relatively cheap, or cost-effective,
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7:05 - 7:07because there's an awful lot of countries involved,
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7:07 - 7:09and some of them are emerging markets,
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7:09 - 7:12some of them emerging countries, low-income.
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7:12 - 7:15And finally, you want something that's species-specific.
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7:15 - 7:17You want to get rid of this mosquito that spreads dengue,
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7:17 - 7:20but you don't really want to get all the other insects.
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7:20 - 7:24Some are quite beneficial. Some are important to your ecosystem.
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7:24 - 7:25This one's not. It's invaded you.
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7:25 - 7:28But you don't want to get all of the insects.
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7:28 - 7:30You just want to get this one.
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7:30 - 7:33And most of the time, you'll find this insect
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7:33 - 7:34lives in and around your home,
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7:34 - 7:38so this -- whatever we do has got to get to that insect.
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7:38 - 7:40It's got to get into people's houses, into the bedrooms,
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7:40 - 7:42into the kitchens.
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7:42 - 7:46Now there are two features of mosquito biology
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7:46 - 7:48that really help us in this project,
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7:48 - 7:52and that is, firstly, males don't bite.
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7:52 - 7:55It's only the female mosquito that will actually bite you.
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7:55 - 7:57The male can't bite you, won't bite you,
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7:57 - 7:59doesn't have the mouth parts to bite you.
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7:59 - 8:01It's just the female.
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8:01 - 8:03And the second is a phenomenon
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8:03 - 8:07that males are very, very good at finding females.
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8:07 - 8:10If there's a male mosquito that you release,
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8:10 - 8:15and if there's a female around, that male will find the female.
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8:15 - 8:19So basically, we've used those two factors.
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8:19 - 8:20So here's a typical situation,
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8:20 - 8:23male meets female, lots of offspring.
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8:23 - 8:25A single female will lay about
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8:25 - 8:26up to 100 eggs at a time,
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8:26 - 8:29up to about 500 in her lifetime.
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8:29 - 8:32Now if that male is carrying a gene
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8:32 - 8:34which causes the death of the offspring,
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8:34 - 8:37then the offspring don't survive,
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8:37 - 8:41and instead of having 500 mosquitos running around,
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8:41 - 8:43you have none.
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8:43 - 8:46And if you can put more, I'll call them sterile,
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8:46 - 8:49that the offspring will actually die at different stages,
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8:49 - 8:51but I'll call them sterile for now.
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8:51 - 8:54If you put more sterile males out into the environment,
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8:54 - 8:58then the females are more likely to find a sterile male
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8:58 - 9:03than a fertile one, and you will bring that population down.
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9:03 - 9:06So the males will go out, they'll look for females,
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9:06 - 9:10they'll mate. If they mate successfully, then no offspring.
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9:10 - 9:13If they don't find a female, then they'll die anyway.
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9:13 - 9:16They only live a few days.
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9:16 - 9:19And that's exactly where we are.
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9:19 - 9:20So this is technology that was developed
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9:20 - 9:23in Oxford University a few years ago.
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9:23 - 9:25The company itself, Oxitec, we've been working
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9:25 - 9:28for the last 10 years, very much on a sort of similar
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9:28 - 9:31development pathway that you'd get with a pharmaceutical company.
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9:31 - 9:35So about 10 years of internal evaluation, testing,
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9:35 - 9:39to get this to a state where we think it's actually ready.
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9:39 - 9:41And then we've gone out into the big outdoors,
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9:41 - 9:43always with local community consent,
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9:43 - 9:45always with the necessary permits.
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9:45 - 9:48So we've done field trials now in the Cayman Islands,
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9:48 - 9:50a small one in Malaysia,
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9:50 - 9:54and two more now in Brazil.
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9:54 - 9:56And what's the result?
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9:56 - 9:59Well, the result has been very good.
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9:59 - 10:02In about four months of release,
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10:02 - 10:04we've brought that population of mosquitos
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10:04 - 10:07— in most cases we're dealing with villages here
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10:07 - 10:10of about 2,000, 3,000 people, that sort of size,
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10:10 - 10:11starting small —
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10:11 - 10:14we've taken that mosquito population down
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10:14 - 10:17by about 85 percent in about four months.
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10:17 - 10:19And in fact, the numbers after that get,
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10:19 - 10:23those get very difficult to count, because there just aren't any left.
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10:23 - 10:24So that's been what we've seen in Cayman,
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10:24 - 10:27it's been what we've seen in Brazil
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10:27 - 10:29in those trials.
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10:29 - 10:32And now what we're doing is we're going through a process
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10:32 - 10:35to scale up to a town of about 50,000,
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10:35 - 10:37so we can see this work at big scale.
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10:37 - 10:40And we've got a production unit in Oxford,
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10:40 - 10:43or just south of Oxford, where we actually produce these mosquitos.
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10:43 - 10:44We can produce them,
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10:44 - 10:47in a space a bit more than this red carpet,
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10:47 - 10:49I can produce about 20 million a week.
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10:49 - 10:51We can transport them around the world.
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10:51 - 10:54It's not very expensive, because it's a coffee cup --
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10:54 - 10:56something the size of a coffee cup
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10:56 - 10:59will hold about three million eggs.
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10:59 - 11:03So freight costs aren't our biggest problem. (Laughter)
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11:03 - 11:06So we've got that. You could call it a mosquito factory.
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11:06 - 11:09And for Brazil, where we've been doing some trials,
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11:09 - 11:11the Brazilian government themselves have now built
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11:11 - 11:13their own mosquito factory, far bigger than ours,
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11:13 - 11:19and we'll use that for scaling up in Brazil.
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11:19 - 11:21There you are. We've sent mosquito eggs.
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11:21 - 11:24We've separated the males from the females.
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11:24 - 11:28The males have been put in little pots
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11:28 - 11:30and the truck is going down the road
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11:30 - 11:33and they are releasing males as they go.
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11:33 - 11:34It's actually a little bit more precise than that.
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11:34 - 11:36You want to release them so that
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11:36 - 11:38you get good coverage of your area.
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11:38 - 11:41So you take a Google Map, you divide it up,
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11:41 - 11:43work out how far they can fly,
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11:43 - 11:45and make sure you're releasing such that you get
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11:45 - 11:47coverage of the area, and then you go back,
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11:47 - 11:49and within a very short space of time,
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11:49 - 11:53you're bringing that population right the way down.
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11:53 - 11:55We've also done this in agriculture.
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11:55 - 11:59We've got several different species of agriculture coming along,
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11:59 - 12:01and I'm hoping that soon
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12:01 - 12:04we'll be able to get some funding together so we can get back
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12:04 - 12:07and start looking at malaria.
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12:07 - 12:09So that's where we stand at the moment,
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12:09 - 12:12and I've just got a few final thoughts,
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12:12 - 12:15which is that this is another way in which biology
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12:15 - 12:19is now coming in to supplement chemistry
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12:19 - 12:23in some of our societal advances in this area,
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12:23 - 12:25and these biological approaches are coming in
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12:25 - 12:28in very different forms,
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12:28 - 12:30and when you think about genetic engineering,
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12:30 - 12:33we've now got enzymes for industrial processing,
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12:33 - 12:36enzymes, genetically engineered enzymes in food.
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12:36 - 12:39We have G.M. crops, we have pharmaceuticals,
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12:39 - 12:40we have new vaccines,
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12:40 - 12:44all using roughly the same technology, but with very different outcomes.
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12:44 - 12:47And I'm in favor, actually. Of course I am.
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12:47 - 12:50I'm in favor of particularly where the older technologies
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12:50 - 12:53don't work well or have become unacceptable.
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12:53 - 12:57And although the techniques are similar,
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12:57 - 12:58the outcomes are very, very different,
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12:58 - 13:00and if you take our approach, for example,
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13:00 - 13:02and you compare it to, say, G.M. crops,
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13:02 - 13:07both techniques are trying to produce a massive benefit.
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13:07 - 13:09Both have a side benefit,
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13:09 - 13:12which is that we reduce pesticide use tremendously.
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13:12 - 13:16But whereas a G.M. crop is trying to protect the plant,
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13:16 - 13:19for example, and give it an advantage,
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13:19 - 13:22what we're actually doing is taking the mosquito
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13:22 - 13:26and giving it the biggest disadvantage it can possibly have,
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13:26 - 13:29rendering it unable to reproduce effectively.
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13:29 - 13:33So for the mosquito, it's a dead end.
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13:33 - 13:37Thank you very much. (Applause)
- Title:
- Re-engineering mosquitos to fight disease
- Speaker:
- Hadyn Parry
- Description:
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In a single year, there are 200-300 million cases of malaria and 50-100 million cases of dengue fever worldwide. So: Why haven’t we found a way to effectively kill mosquitoes yet? Hadyn Parry presents a fascinating solution: genetically engineering male mosquitoes to make them sterile, and releasing the insects into the wild, to cut down on disease-carrying species.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDTalks
- Duration:
- 13:57
Thu-Huong Ha edited English subtitles for Re-engineering mosquitos to fight disease | ||
Thu-Huong Ha approved English subtitles for Re-engineering mosquitos to fight disease | ||
Thu-Huong Ha edited English subtitles for Re-engineering mosquitos to fight disease | ||
Thu-Huong Ha edited English subtitles for Re-engineering mosquitos to fight disease | ||
Morton Bast accepted English subtitles for Re-engineering mosquitos to fight disease | ||
Morton Bast edited English subtitles for Re-engineering mosquitos to fight disease | ||
Joseph Geni added a translation |