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Eco-Justice Notes
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Kill All the Mosquitos?
distributed 6/10/16 - ©2016

The cover story of June's Smithsonian Magazine poses an urgent and challenging ethical question. The headline of the print version puts it this way:

A world without mosquitos: New gene-editing technology gives scientists the ability to wipe out the carriers of malaria and the Zika virus. But should they use it?

The Smithsonian article was timely. This week a committee of the National Academies of Sciences, Engineering, and Medicine released a report on the topic. Science Magazine wrote: "U.S. Academies gives cautious go-ahead to gene drive". But Genetic Engineering & Biotechnology News said: "Put the Brakes on Gene Drive, Says Safety-Minded National Academies".

Perhaps the most helpful advice come from Vox: "'Gene drive.' Learn the term. Because it could one day transform the world."

The fear factor related to Zika -- and especially the discovery that Zika causes microcephaly -- generates headlines for genetic technologies that might provide a Zia defense. The sudden interest in such powerful new tools calls for informed and thoughtful decisions by scientists, public health officials, politicians ... and ordinary folk.

Today's Notes will take a first look at some of these issues -- because the options are more complex than the headlines suggest -- and suggest some ethical considerations that need to be part of the conversation.

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First off, what is this "gene drive" thing? Very briefly, it involves two aspects of the rapidly-advancing field of genetic modification. A new technique (called CRISPR) allows for very precise editing of genetic information. The editing is done in a way that virtually guarantees that the changed genes will be passed along into future generations of the modified species. Other GM approaches don't spread well, but this combination "drives" the genes into populations.

The Science magazine article notes: "Gene drive is so different from other technologies involving genetic modification that it requires a whole new way of thinking about how to evaluate and regulate it ... To date, regulations have centered on containing genetically modified organisms. But with gene drive the goal is for the modification to spread."

Gene drive can be used with many species -- perhaps even humans -- but the current buzz is about mosquitos, because of the role of those insects in spreading diseases like Zika, malaria, dengue, yellow fever and West Nile virus.

Bill Gates -- whose foundation is deeply concerned about such things -- call mosquitos "the deadliest animal in the world." His statistics (which "have wide error margins"!) bear that out. In a typical year, worldwide, sharks kill 10 people, and crocodiles 1,000. Dogs kill 25,000, mostly by transmitting rabies, and snakes kill 50,000. Humans, with a mind-boggling array of lethal approaches, kill 475,000 other humans. And in one year, mosquitos kill 725,000 people. If you want to make the world a safer place, skeeters are the logical target.

Of course -- and this figures into the ethical considerations -- humans have tried many ways to control mosquitos, especially since their role in the spread of disease became known. Swamps are drained, or covered with oil slicks. Insecticides are sprayed in massive quantities. Nets and insect repellants help keep the bugs away. Gene drive now raises the possibility of taking insect control to amazing new levels of effectiveness.

Despite the headline of "A world without mosquitos", genetic technologies would target single species of them. There are 3,500 species of mosquito on the planet, and only about 100 of those spread human disease. The Smithsonian article suggests that gene drive strategies "might want to stop at fewer than a dozen species in three genera" -- which is hardly a wholesale elimination of all mosquitos. And the GM approach might be used rather locally, in areas of the highest disease risk, without trying to wipe out every malaria-spreading insect.

There's also the possibility of using genetic modification to do away with the pathogen, not the insect. If a strain of mosquitos could be developed that produce that antibodies against the malaria parasite, then the disease is controlled without exterminating the insect.

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It may be five years or more before gene drive could be put to an actual field test, releasing modified insects into the wild. That is not a long time to consider the ecological and ethical implications. Here are a few of the topics that need research and reflection.

  • There is the question related to all genetic modification: do we have the right -- and the wisdom -- to "play God" with the tweaking of these life patterns? And do we have the right to intentionally force another species into extinction? As I mentioned above, though, humans have been trying very hard to exterminate mosquitos for a century. Genetic modification does provide a way to do that which is carefully targeted at a single species. Using GM technology could greatly reduce the use of broad-spectrum insecticides.

  • The ecological repercussions of removing one or several species of insects -- whether locally or globally -- are not known. In some locations, the impact might be trivial. In other places, the loss of mosquitos would be catastrophic. (The Arctic is the most often mentioned example.) Determining the significance of a single species in multiple expressions of a complex ecological web is an incredibly difficult project. But, as the Vox article put it, "when you're messing with 100 million years of evolution, you want to be careful."

  • With this new technology, which is intended to spread widely through the natural world, the standards and processes for decision-making need to be clear and extensive. All stakeholders, and all impacted communities, must have a say in whether the technology will be employed with a particular species and in a certain ecosystem. This probably will involve gradual steps in the development of research, and case-by-case decisions on each application. There is, as yet, no good model for this scale of public engagement.

  • There are signs that the gene drive technologies for insect control could be very big business. Patents and deployment methods could be immensely profitable. Controls must be established to ensure that ecological stability and public health are the primary motivations, and not corporate profits.

  • A last consideration -- which I have not seen in print about this new technology -- becomes very important if gene drive is as successful as some hope. If mosquitos now cause 725,000 deaths per year, many of them young children, and if that death rate is cut in half, then we've initiated one more factor leading to substantial growth in the human population. As I described back in 2005, most of the population explosion of the last 100 years has not come from greater fertility, but through great steps at extending life spans. The presumed ethical good of slashing death and disability from insect-borne pathogens does have a flip side in adding millions more to an already over-populated planet.

The prospect of stopping Zika from its rapid and devastating spread is enticing. There will be many who call for the quick and poorly-tested use of gene drive technologies to wipe out the mosquitos that spread the disease. That temptation, though, needs to be resisted.

The gene drive approach to genetic modification spreads its effects quickly and widely though an ecosystem, and there is no way to call it back one it is released. We need to know much more about the possible ecological repercussions, and about the frameworks for policy decisions, before moving ahead with the application of this new and powerful technology.

Shalom!

Peter Sawtell
Executive Director
Eco-Justice Ministries

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