A secret weapon against Zika and other mosquito-borne diseases | Nina Fedoroff

50,710 views ・ 2017-06-15

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Zika fever:
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our newest dread disease.
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What is it? Where'd it come from?
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What do we do about it?
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Well for most adults, it's a relatively mild disease --
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a little fever, a little headache, joint pain, maybe a rash.
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In fact, most people who get it don't even know they've had it.
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But the more we find out about the Zika virus
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the more terrifying it becomes.
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For example, doctors have noticed an uptick
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of something called Guillain-Barré syndrome in recent outbreaks.
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In Guillain-Barré, your immune system attacks your nerve cells
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it can partially or even totally paralyze you.
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Fortunately, that's quite rare, and most people recover.
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But if you're pregnant when you're infected
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you're at risk of something terrible.
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Indeed, a child with a deformed head.
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Here's a normal baby.
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Here's that infant with what's called microcephaly.
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a brain in a head that's too small.
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And there's no known cure.
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It was actually doctors in northeastern Brazil
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who first noticed, just a year ago, after a Zika outbreak,
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that there was a peak in the incidence of microcephaly.
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It took medical doctors another year
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to be sure that it was caused by the Zika virus,
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but they're now sure.
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And if you're a "bring on the evidence" type,
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check out this publication.
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So where did it come from, and how did it get here?
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And it is here.
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Like many of our viruses, it came out of Africa,
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specifically the Zika forest in Uganda.
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Researchers at the nearby Yellow Fever Research Institute
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identified an unknown virus in a monkey in the Zika forest
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which is how it got its name.
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The first human cases of Zika fever
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surfaced a few years later in Uganda-Tanzania.
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The virus then spread through West Africa
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and east through equatorial Asia -- Pakistan, India, Malaysia, Indonesia.
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But it was still mostly in monkeys and, of course, mosquitoes.
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In fact in the 60 years between the time it was first identified in 1947 and 2007
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there were only 13 reported cases of human Zika fever.
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And then something extraordinary happened on the tiny Micronesian Yap islands.
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There was an outbreak that affected fully 75 percent of the population.
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How did it get there? By air.
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Today we have two billion commercial airline passengers.
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An infected passenger can board a plane, fly halfway around the world
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before developing symptoms -- if they develop symptoms at all.
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Then when they land, the local mosquitoes begin to bite them and spread the fever.
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Zika fever then next surfaced in 2013 in French Polynesia.
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By December of that year, it was being transmitted locally by the mosquitoes.
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That led to an explosive outbreak in which almost 30,000 people were affected.
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From there it radiated around the Pacific.
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There were outbreaks in the Cook Islands, in New Caledonia,
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in Vanuatu, in the Solomon Islands
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and almost all the way around to the coast of South America and Easter Island.
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And then, in early 2015,
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there was an upsurge of cases of a dengue-like syndrome
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in the city of Natal in northeastern Brazil.
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The virus wasn't dengue, it was Zika, and it spread rapidly --
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Recife down the coast, a big metropolitan center, soon became the epicenter.
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Well people have speculated that it was 2014 World Cup soccer fans
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that brought the virus into the country.
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But others have speculated that perhaps it was Pacific Islanders
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participating in championship canoe races
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that were held in Rio that year that brought it in.
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Well today, this is only a year later.
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The virus is being locally transmitted by mosquitoes
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virtually throughout South America, Central America, Mexico
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and the Caribbean Islands
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Until this year, the many thousands of cases
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that have been diagnosed in the US were contracted elsewhere.
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But as of this summer, it's being transmitted locally in Miami.
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It's here.
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So what do we do about it?
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Well, preventing infection
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is either about protecting people or about eliminating the mosquitoes.
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Let's focus on people first.
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You can get vaccinated.
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You can not travel to Zika areas.
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Or you can cover up and apply insect repellent.
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Getting vaccinated is not an option, because there isn't a vaccine yet
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and there probably won't be for a couple of years.
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Staying home isn't a foolproof protection either
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because we now know that it can be sexually transmitted.
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Covering up and applying insect repellent does work ...
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until you forget.
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(Laughter)
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So that leaves the mosquitoes, and here's how we control them now:
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spraying insecticides.
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The protective gear is necessary because these are toxic chemicals
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that kill people as well as bugs.
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Although it does take quite a lot more to kill a person than to kill a bug.
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These are pictures from Brazil and Nicaragua.
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But it looks the same in Miami, Florida.
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And we of course can spray insecticides from planes.
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Last summer, mosquito control officials in Dorchester County, South Carolina,
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authorized spraying of Naled, an insecticide,
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early one morning, as recommended by the manufacturer.
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Later that day, a beekeeper told reporters
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that her bee yard looked like it had been nuked.
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Oops.
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Bees are the good guys.
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The citizens of Florida protested, but spraying continued.
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Unfortunately, so did the increase in the number of Zika fever cases.
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That's because insecticides aren't very effective.
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So are there any approaches that are perhaps more effective than spraying
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but with less downsides than toxic chemicals?
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I'm a huge fan of biological controls,
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and I share that view with Rachel Carson, author of "Silent Spring,"
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the book that is credited with starting the environmental movement.
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In this book she tells the story, as an example,
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of how a very nasty insect pest of livestock
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was eliminated in the last century.
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No one knows that extraordinary story today.
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So Jack Block and I, when we were writing an editorial
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about the mosquito problem today, retold that story.
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And in capsule form, it's that pupae -- that's the immature form of the insect --
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were irradiated until they were sterile, grown to adulthood
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and then released from planes all over the Southwest,
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the Southeast and down into Mexico and into Central America
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literally by the hundreds of millions from little airplanes,
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eventually eliminating that terrible insect pest
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for most of the Western Hemisphere.
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Our real purpose in writing this editorial
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was to introduce readers to how we can do that today --
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not with radiation but with our knowledge of genetics.
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Let me explain.
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This is the bad guy: Aedes aegypti.
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It's the most common insect vector of diseases,
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not just Zika but dengue, Chikungunya, West Nile virus
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and that ancient plague, yellow fever.
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It's an urban mosquito,
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and it's the female that does the dirty work.
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She bites to get a blood meal to feed her offspring.
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Males don't bite; they don't even have the mouth parts to bite.
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A little British company called Oxitec genetically modified that mosquito
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so that when it mates with a wild female, its eggs don't develop to adulthood.
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Let me show you.
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This is the normal reproductive cycle.
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Oxitec designed the mosquito so that when the male mates with the wild female
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the eggs don't develop.
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Sounds impossible?
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Well let me show you just diagrammatically how they do it.
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Now this represents the nucleus of a mosquito cell,
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and that tangle in the middle represents its genome,
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the sum total of its genes.
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Scientists added a single gene
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that codes for a protein represented by this orange ball
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that feeds back on itself to keep cranking out more of that protein.
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The extra copies, however, go and gum up the mosquitoes' genes,
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killing the organism.
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To keep it alive in the laboratory they use a compound called tetracycline.
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Tetracycline shuts off that gene and allows normal development.
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They added another little wrinkle so that they could study what happens.
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And that is they added a gene that makes the insect glow under UV light
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so that when they released it they could follow exactly how far it went
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how long it lived and all of the kinds of data
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for a good scientific study.
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Now this is the pupal stage, and at this stage
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the females are larger than the males.
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That allows them to sort them into the males and the females
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and they allow only the males to grow to adulthood.
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And let me remind you that males don't bite.
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From there it's pretty simple.
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They take beakers full of male mosquitoes,
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load them into milk cartons, and drive around the city,
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releasing them guided by GPS.
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Here's the mayor of a city releasing the first batch
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of what they call the "friendly Aedes."
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Now I wish I could tell you this is an American city, but it's not.
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It's Piracicaba, Brazil.
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The amazing thing is that in just a year
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it brought down the cases of dengue by 91 percent.
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That's better than any insecticide spraying can do.
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So why aren't we using this remarkable biological control in the US?
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That's because it's a GMO: a genetically modified organism.
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Notice the subtitle here says if the FDA would let them
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they could do the same thing here, when Zika arrives.
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And of course it has arrived.
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So now I have to tell you the short form
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of the long, torturous story of GM regulation in the US
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In the US, there are three agencies that regulate genetically modified organisms:
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the FDA, the Food and Drug Administration,
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the EPA, the Environmental Protection Agency,
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and the USDA, US Department of Agriculture.
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Took these folks two years to decide that it would be the FDA
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that would regulate the genetically modified mosquito.
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And they would do it as a new animal drug, if that makes any sense.
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Took them another five years going back and forth and back and forth
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to convince the FDA that this would not harm people,
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and it would not harm the environment.
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They finally gave them, this summer, permission to run a little test
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in the Florida Keys,
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where they had been invited years earlier when they Keys had an outbreak of dengue.
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Would that it were that easy.
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When the local residents heard
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that there would be genetically modified mosquitoes tested in their community
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some of them began to organize protests.
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They even organized a petition on the internet with this cuddly logo,
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which eventually accumulated some 160,000 signatures
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And they demanded a referendum
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which will be conducted in just a couple of weeks
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about whether the trials would be permitted at all.
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Well it's Miami that really needs these better ways of controlling insects.
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And there the attitudes are changing.
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In fact, very recently a bipartisan group of more than 60 legislators
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wrote to HHS Secretary Sylvia Burwell
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asking that she, at the Federal level, expedite access for Florida
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to this new technology.
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So the bottom line is this:
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biological control of harmful insects
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can be both more effective and very much more environmentally friendly
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than using insecticides, which are toxic chemicals.
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That was true in Rachel Carson's time; it's true today.
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What's different is that we have enormously more information
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about genetics than we had then,
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and therefore more ability to use that information
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to affect these biological controls.
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And I hope that what I've done is aroused your curiosity enough
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to start your own inquiry -- not into just GM mosquitoes
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but to the other genetically modified organisms that are so controversial today.
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I think if you do that, and you dig down through all of the misinformation,
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and the marketing
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on the part of the organic food industry and the Greenpeaces
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and find the science, the accurate science,
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you'll be surprised and pleased.
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Thank you.
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(Applause)
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