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Being at Two with Nature and Mosquitoes

When Woody Allen said he was “at two with nature,” perhaps he had in mind insects that sting or bite. Who can argue with that, and who hasn’t taken a swat at one in self-defense? Right now the creature we would like to get rid of is one common species of mosquito called Ades aegypti. Unfortunately for us—and for them—some of these mosquitoes transmit very serious viruses, including dengue fever, chikungunya virus, and the one that is frightening us most at the moment, the Zika virus. We are about to take a collective swat at it with a very powerful new weapon.

Zika spread by the Ae. aegypti has become a serious medical problem in South America, particularly in portions of Brazil, and it has arrived in the United States. At the end of August, the Centers for Disease Control and Prevention reported that 624 pregnant women were known to be infected with Zika and that there had been 16 cases of impaired babies born to infected mothers. It is unknown how many of these birth defects were caused by the virus or by other factors. Thanks to relatively favorable social and economic conditions, ordinary mitigation measures available to public health programs will be able to contain the spread of the Zika infection in this country. The prospect is grimmer for countries such as Brazil. In any country, though, the consequences for newborn infants and older children and the alarm of women of childbearing age are very compelling.

Regarding these mosquitoes, should we become at two with nature? And how much at two should we be? When we get all riled up, we tend to escalate the warfare and bring increasingly lethal and high-tech weapons to the fight. Science and technology are obliging and soon this will involve the use of new forms of genetic engineering known as “gene editing” and “gene drives.” These technologies are powerful, and genetic escalation should not be undertaken lightly.

A leader in the field of genetically engineering mosquitoes is Oxitec, a British-based company that uses genetic engineering to alter male Ae. aegypti mosquitoes in the laboratory so that they will pass a lethal genetic trait to their male offspring. Then it releases millions of these genetically modified insects into the wild to mate. Oxitec has experimented with this approach in Brazil, Panama, and the Cayman Islands, and is proposing to do so in the Florida Keys. Relying on studies by the company, the U.S. Food and Drug Administration has given its approval for an experiment in Key Haven, a small community outside of Key West, saying that the release would be safe for humans (males do not bite and cannot transmit Zika) and the disappearance of all or most of the Ae. aegypti would make no difference to the ecosystem.

On November 8, residents of Monroe County, Fla. will have a referendum on their ballots concerning the use of GM mosquitoes countywide, and the residents of Key Haven will also vote on whether they want their community to be the site of the proposed Oxitec field experiment. The Florida Keys Mosquito Control District will have the final say on this, but it will be politically difficult for it to give approval if a majority says no to GM mosquitoes in the voting booth.

Oxitec uses gene editing, but in the future a slightly different approach using gene drives will be available to reengineer a species of insects (and other organisms) by genetically altering a few individuals to have desired traits (such as sterility or resistance to blight). This is done in such a way that, instead of the usual 50-50 chance that applies to natural genetic inheritance, it would be almost certain these traits would be passed along to offspring and spread quickly throughout the entire population. (More information on gene drives can be found here.) Natural selection and traditional animal and plant breeding by humans change species, of course, but very slowly, by trial and error. By contrast, gene drives are a kind of unnatural selection that operates rapidly and could make big mistakes. Bioengineers today have far more know-how than they have wisdom about why they are using this technology or exactly what they are doing with it. We may win the battle against Ae. aegypti and Zika, but lose the war if we take on nature and evolution itself in this radical way.

There are serious reasons to drive genes using prudent and cautious brakes, to go slowly, and to look both ways. Individual mosquitoes are not important as such, but as a population or a species in the web of life, they are. No species is essential to life as such, including human beings. But then no species, including mosquitoes, is simply expendable, either. Mosquitoes have lived on Earth for 100 million years, far longer than we have. They feed—and feed upon—other animals. Their behavior is pestiferous to many animals besides us, but precisely in this way they influence behaviors that are functional for the ecosystems they co-inhabit. Without mosquitoes, the ecological functions they have contributed to would change. Perhaps for the better, perhaps for the worse—scientists frankly do not know for sure. Human health would definitely improve in the short run. Yet in the long run, the viruses mosquitoes now carry to humans will come to be carried by something else.

In ecology there is almost never only one problem, one cause, and one solution. Life—both metaphorically and biologically—is not that simple. When humans intervene in natural systems, we can never do just one thing. We almost always think we can, and then find out we have triggered other things with unforeseen results.

The use of biotechnology is too powerful and too far-reaching in its consequences to be left up to corporate decision-makers, the profit motive, and the unregulated free market place alone. As democratic citizens we must rise to the occasion of governing this new technology. We should have a strong public health consciousness, to be sure, but we also should have an ecological conscience. We need to have the virtues of prudence, humility, and an abiding interest in the common good of all life. And when it comes to controlling evolution with gene drives, we should not be driven by fear, nor should we drive without moral brakes.

Bruce Jennings is an adjunct associate professor at Vanderbilt University, a senior fellow at the Center for Humans and Nature, and a senior advisor at The Hastings Center and a Hastings Center Fellow. His most recent book is Ecological Governance: Toward a New Social Contract with the Earth, published this year.

Published on: October 4, 2016
Published in: Hastings Bioethics Forum, Humans and Nature

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