So Jack Block and I, when we were writing an editorial about the mosquito problem today, retold that story. And in capsule form, it’s that pupae — that’s the immature form of the insect — were irradiated until they were sterile, grown to adulthood and then released from planes all over the Southwest, the Southeast and down into Mexico and into Central America literally by the hundreds of millions from little airplanes, eventually eliminating that terrible insect pest for most of the Western Hemisphere. Our real purpose in writing this editorial was to introduce readers to how we can do that today — not with radiation but with our knowledge of genetics. Let me explain.
This is the bad guy: Aedes aegypti. It’s the most common insect vector of diseases, not just Zika but dengue, Chikungunya, West Nile virus and that ancient plague, yellow fever. It’s an urban mosquito, and it’s the female that does the dirty work. She bites to get a blood meal to feed her offspring. Males don’t bite; they don’t even have the mouth parts to bite. A little British company called Oxitec genetically modified that mosquito so that when it mates with a wild female, its eggs don’t develop to adulthood. Let me show you.
This is the normal reproductive cycle. Oxitec designed the mosquito so that when the male mates with the wild female the eggs don’t develop. Sounds impossible? Well let me show you just diagrammatically how they do it. Now this represents the nucleus of a mosquito cell, and that tangle in the middle represents its genome, the sum total of its genes. Scientists added a single gene that codes for a protein represented by this orange ball that feeds back on itself to keep cranking out more of that protein. The extra copies, however, go and gum up the mosquitoes’ genes, killing the organism.
To keep it alive in the laboratory they use a compound called tetracycline. Tetracycline shuts off that gene and allows normal development. They added another little wrinkle so that they could study what happens. And that is they added a gene that makes the insect glow under UV light so that when they released it they could follow exactly how far it went how long it lived and all of the kinds of data for a good scientific study. Now this is the pupal stage, and at this stage the females are larger than the males. That allows them to sort them into the males and the females and they allow only the males to grow to adulthood.
And let me remind you that males don’t bite. From there it’s pretty simple. They take beakers full of male mosquitoes, load them into milk cartons, and drive around the city, releasing them guided by GPS. Here’s the mayor of a city releasing the first batch of what they call the “friendly Aedes.” Now I wish I could tell you this is an American city, but it’s not. It’s Piracicaba, Brazil. The amazing thing is that in just a year it brought down the cases of dengue by 91 percent. That’s better than any insecticide spraying can do.
So why aren’t we using this remarkable biological control in the US? That’s because it’s a GMO: a genetically modified organism. Notice the subtitle here says if the FDA would let them they could do the same thing here, when Zika arrives. And of course it has arrived. So now I have to tell you the short form of the long, torturous story of GM regulation in the US In the US, there are three agencies that regulate genetically modified organisms: the FDA, the Food and Drug Administration, the EPA, the Environmental Protection Agency, and the USDA, US Department of Agriculture. Took these folks two years to decide that it would be the FDA that would regulate the genetically modified mosquito. And they would do it as a new animal drug, if that makes any sense. Took them another five years going back and forth and back and forth to convince the FDA that this would not harm people, and it would not harm the environment.
They finally gave them, this summer, permission to run a little test in the Florida Keys, where they had been invited years earlier when they had an outbreak of dengue. [Would that it were that easy]. When the local residents heard that there would be genetically modified mosquitoes tested in their community some of them began to organize protests. They even organized a petition on the internet with this cuddly logo, which eventually accumulated some 160,000 signatures And they demanded a referendum which will be conducted in just a couple of weeks about whether the trials would be permitted at all.
Well it’s Miami that really needs these better ways of controlling insects. And there the attitudes are changing. In fact, very recently a bipartisan group of more than 60 legislators wrote to HHS Secretary Sylvia Burwell asking that she, at the Federal level, expedite access for Florida to this new technology.
So the bottom line is this: biological control of harmful insects can be both more effective and very much more environmentally friendly than using insecticides, which are toxic chemicals. That was true in Rachel Carson’s time; it’s true today. What’s different is that we have enormously more information about genetics than we had then, and therefore more ability to use that information to affect these biological controls.
And I hope that what I’ve done is aroused your curiosity enough to start your own inquiry — not into just GM mosquitoes but to the other genetically modified organisms that are so controversial today. I think if you do that, and you dig down through all of the misinformation, and the marketing on the part of the organic food industry and the Greenpeaces and find the science, the accurate science, you’ll be surprised and pleased.