How to End Malaria Once and for All | Abdoulaye Diabaté | TED

25,517 views ・ 2024-08-21

TED


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00:03
(Mosquitoes buzzing)
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Mosquitoes.
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I don't know about you,
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but I don't have a good relationship with them.
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(Laughter)
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A friend of mine said one day,
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if you think that you are too small to make a big difference,
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you've never spent a night with mosquitoes in a room.
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(Laughter)
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But ...
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I don't have any mosquitoes in my pocket to release tonight,
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so it's going to be fine.
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So let's start.
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As unbelievable as it may sound, malaria is as old as humankind.
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And malaria once was a public health issue all over the world.
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But then it has been successfully tackled in the US and Europe.
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And yet, decades later,
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malaria still kills millions of people
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in Africa
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and in Asia.
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Why?
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I'm Abdoulaye Diabaté, a medical entomologist
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from l'Institut de Recherche en Science de la Santé.
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I'm here today,
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flying all the way from Burkina Faso,
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to tell you that we might be closer than ever
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to eliminate malaria in Africa.
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(Applause)
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Thank you.
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Malaria is tightly linked to poverty.
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But then you have no idea of how expensive it is to be poor.
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There are 200 million cases worldwide
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that end up sadly every year with about 600,000 deaths.
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And this is not a random collection of statistics on a piece of paper.
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Behind each of these 600,000 deaths,
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there is a personal, tragic story, sometimes behind closed doors.
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Most of these deaths happen in Africa.
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Children and pregnant women bear the highest burden.
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And I'm a fortunate childhood malaria survivor.
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When I was a kid, I used to think that my dad was a superhero.
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I could see him leaving the house every morning at six,
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riding his bicycle to the farm, working very hard all day long.
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We did not have much for living.
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But who said you need more to be happy?
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But when happiness hangs by a thread,
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it doesn't take much to turn your life around.
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My certainty in my dad got deeply shaken the day I got struck down by malaria.
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I was three or four years old.
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As we used to say in my country,
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kids may not understand the complexity of suffering,
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but pain has no age.
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And gosh, I was in pain.
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I can still clearly see myself
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laying down there on the bed with high fever and suffering.
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I could not eat anything.
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Throwing up all the time.
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Will I survive? Will I not?
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The psychological trauma my parents were going through
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was unbearable.
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But against all odds, I survived.
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But can we say today that we are done with malaria
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because Diabaté survived and made it all the way down to Vancouver?
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If I say yes, no one can blame me.
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But it’s a lie, because many children are still dying of malaria.
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The real question then is:
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Why have we not been able to defeat it so far?
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Well because malaria is a complex parasitic disease
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that plays on three grounds.
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Plasmodium, the pathogen;
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anopheles, the vector;
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and human, the victim.
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Each of these elements is very complex on its own,
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and the interactions make it even more complex
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to devise interventions that are really effective.
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But of course we are trying.
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Currently, there are two vaccines to immunize people,
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but the heavy logistics to deliver this vaccine
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may not allow us to reach their full potential.
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Bed nets and first-hand treatment
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are both threatened by insecticide and drug resistance,
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meaning that our best interventions have started to fail.
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And there is a general consensus today that without additional new tools,
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we may never cross the last mile of malaria elimination.
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And this is exactly where I come in.
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My colleagues and I at Target Malaria,
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and are working on something called gene drive:
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a way to control mosquito population and halt malaria transmission.
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So what is gene drive?
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It's a natural molecular mechanism
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that augments the frequency of a certain gene in the population
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beyond the normal Mendelian inheritance.
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So what does it mean?
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If you take any gene,
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in natural circumstances,
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it has only a 50 percent chance of being transmitted to the next generation.
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Meaning that if the parents have 100 babies, like in mosquitoes,
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only 50 of them will get the gene and the other 50 will not.
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But not all genes behave this way in nature.
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Some genes have found a very clever way to bypass this law,
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and can augment their own prospect to up to 90 percent.
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Such genes are said to drive, and so the name "gene drive."
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Our most promising strain affects female fertility
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by targeting a gene called doublesex.
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This gene is responsible for the sex determination in mosquitoes,
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and so disrupting the doublesex gene
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may affect the sexual development for adult mosquitoes
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and their reproduction.
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Now
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it may sound counterintuitive to affect female fertility
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and spread a gene of interest in mosquito population at the same time.
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But it's working.
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And let me show you how.
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We target a specific region of the gene called doublesex
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that affects only females.
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Males bearing this modified gene are not affected at all.
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Females with just one copy of the altered gene are fully fertile.
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However, females bearing two copies
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of the modified gene
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cannot lay eggs,
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fail to bite
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and also have the physical characteristics of both male and female.
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It's called a suppression strategy.
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Once these mosquitoes are released in the field,
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they're going to spread the gene of interest to the wild population,
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and this is going to reduce dramatically their reproductive capacity.
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Fewer mosquitoes means less malaria transmission
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until it stops.
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Mathematical models predict
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that releasing such mosquitoes in the field
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is going to stop malaria transmission in just 20 generations.
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That means in two years.
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And the technology is sustainable,
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cost-effective and easy to deploy,
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as the released mosquitoes will do the job themselves
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by finding the last hiding pocket of wild mosquitoes to convert.
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Fantastic.
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The only problem,
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gene drive has never been tested anywhere in Africa.
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And while the technology brings a lot of hope,
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it also carries its share of fear and skepticism.
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The pathway from the bench to the field
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is not straightforward and is full of pitfalls.
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Maybe the mosquitoes in the field
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will develop resistance to the spread of the transgene.
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Or maybe two countries don't agree,
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but released mosquitoes do not respect the human borders.
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Or also, maybe there are risks to the environment.
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And finally, the community that we are working with
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need to feel comfortable about this technology
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and give us the green light to operate.
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And so for such,
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Target Malaria has adopted an incremental approach, step by step,
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whereby we will start releasing first non-gene-drive mosquitoes,
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meaning that the gene of interest here cannot self-propagate
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and will just go extinct in a few generations.
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The gene drive, the exposure of this gene to the environment
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is incrementally augmented
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in a way that we start first with small cages
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and big indoor cages in Europe,
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and then these mosquitoes are sent to Burkina Faso,
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where they are tested in a contained facility first,
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and subsequently in a big indoor small cage field release.
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Now the gene drive mosquitoes are going to be tested in an open field
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only after this preliminary step
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and the potential risks have been looked at very carefully.
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And also additional research questions have been developed
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to address these risks, if any.
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Now the question, how far are we from releasing gene drive?
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Four to five years.
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But let me tell you this.
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Gene drive mosquitoes are already in the lab,
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and releasing them in the field
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is not going to take us more than 30 minutes.
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But we need five years to get ready for these 30 minutes.
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And why is that?
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The answer is simple.
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Because we need to engage the community
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and get the social license to operate.
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And so if there is one thing that you cannot afford the luxury to miss,
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it's the stakeholder engagement.
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I cannot just pop up in a village with a bucket of mosquitoes
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on the assumption that I'm a scientist working for the public good.
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It will not take anyone a PhD to understand
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if we are respectful of their values or not.
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We need to engage the community
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and then co-develop the technology with them.
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And so for that,
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we've built our engagement strategy on the pyramidal structure,
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starting with the villages where we operate
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all the way to the top with the government officials.
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The engagement is done step-by-step.
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It’s done in an inclusive way
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and also is done in full transparency.
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Ladies and gentlemen,
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there is one more thing that needs to be done
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before gene drive can be released in the field in Africa.
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That is capacity building.
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Gene drive holds a lot of promises,
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but it will not take us anywhere
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if we Africans aren’t enabled to run it on our own.
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Sadly,
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the technical platform in Africa is really very poor,
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and this has to be solved before we can really beat malaria.
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And so for that, we've set up in Burkina Faso
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a World Bank-funded center of excellence on vector-borne diseases, like malaria.
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And also with additional funds from the Gates Foundation,
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we are building a critical mass of next generation scientists
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all over the continent
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to fill the knowledge gap and the know-how gap as well.
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In April 1969, a child was born in a remote village of Burkina Faso.
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Like any other child of the world,
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he had dreams and expectations.
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Sadly, however, as he came to learn,
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the place where you are born in on this planet
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very often affects your perspective on life,
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and may even set the path you need to walk through into your future.
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That shouldn't be the case.
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We are all citizens of the world.
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Our dreams and aspirations should not be constrained
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by the place where we are born.
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And this is the reason why I became a scientist.
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To offer endless possibility to any child anywhere on this continent,
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so that they can see the future with hope.
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But there is no hope if you are cut short with malaria.
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But Target Malaria is here to fix that.
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A world free of malaria is our vision.
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And I will say, yes, we can.
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Thank you for your attention.
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(Applause)
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