Save the Mosquitos

We should fight Zika with better public health, not genetically modified mosquitos.

Puerto Rico’s first Zika case was confirmed in December, and the island’s governor declared a public health emergency on February 5, making the US territory the new frontline in the hemispheric epidemic. According to the Centers for Disease Control and Prevention, a quarter of the territory’s 3.5 million citizens will contract the Zika virus within a year, and eventually 80 percent or more will most likely be infected.

Zika could not have landed in Puerto Rico at a worse time. US-based hedge funds have sent the country, and its crumbling health care system, into a tailspin. Thousands of public workers, who would otherwise be combating the virus, have been laid off. Worse still, scientists recently discovered that Aedes aegypti, the species that spreads Zika and other diseases like dengue and chikungunya, has developed virtual immunity to most chemical insecticides.

Puerto Rican health authorities are alarmed. The island’s health secretary, Dr Ana Ríus, has advised women to delay pregnancy until the epidemic is over, and the government has frozen the price of condoms, insect repellant, and window screens. We won’t know if Puerto Rican authorities succeed in containing Zika for some time, but the prospect of failure is worrying.

Zika has been linked to microcephaly (smaller-than-normal head size in infants) and to the neurological Guillain-Barré syndrome, which causes paralysis in adults. And with Puerto Rico’s permeable border with the US and its debt-driven exodus to the mainland, the looming Zika epidemic now threatens the world’s superpower. This may help explain why Zika — until recently confined to the nations of the Global South — has been raised to the level of a global health emergency.

Needless to say, there are strong incentives to find novel treatments for Zika and similar epidemics. So far there’s no vaccine for the disease, but scientists are considering another solution: drive the Aedes aegypti mosquito to extinction.

To do this, researchers propose using a radical new genetic-engineering technology known as Crispr, which allows scientists to alter the genetic code of any organism. By coupling Crispr with another new technology called a gene drive, scientists can introduce edited genes into entire populations of animals and plants with remarkable rapidity. US-based researchers want to use these two new technologies to sterilize the Aedes populations, leading to the effective extinction of the species, and, if all goes according to plan, to the end of the Zika epidemic.

A few technical challenges remain before the liquidation plan can be implemented. Thousands of genetically altered male mosquitoes would have to be introduced in order to spread sterility effectively through an island population as large as Puerto Rico’s.

But this hurdle isn’t insurmountable. Companies like Oxitec, a British firm currently carrying out trials with genetically engineered mosquitoes in Brazil, are trying to make the technology work in the real world, and turn a profit doing so.

So we might be able to do it. But should we?

Admittedly, there is little love lost between humans and mosquitos. Mosquitoes lack the gruesome charisma of sharks, tigers, or alligators, but are far more deadly than any large predator: they are the vectors for diseases that experts estimate are responsible for the death of half the people who have ever lived. Today, diseases carried by the two hundred or so species of mosquitoes that bite humans kill about 725,000 people a year.

And of those people, the world’s poor are especially affected. In Puerto Rico as in Brazil, where the link between the virus and microcephaly was discovered, those who cannot afford air conditioning, who lack access to adequate sewage collection, and who have been largely ignored by the state will be the hardest hit.

Similarly, malaria, transmitted by the two-dozen or so species of the Anopheles mosquito, kills a shocking six hundred thousand people per year, the vast majority of them in once-colonized tropical countries in South America, Africa, and South and Southeast Asia. As urbanization increases in such countries, the imperative to eradicate the disease-bearing predators that thrive in such conditions will become more pressing.

But what about the environmental impact of liquidating mosquitos from their present ecosystems? As its name suggests, Aedes aegypti hails from east Africa, and is therefore an invasive species in other parts of the world. Some animals like birds and bats subsist on mosquitoes, but these animals have other food supplies. Many biologists argue that the mosquito does not occupy an essential ecological niche. No one, in other words, would miss it once it’s gone.

Unseen Consequences

Yet while it might be nice to consign all mosquitoes to oblivion, the Crispr gene drive technology would not achieve this. Because it only targets the Aedes, it is in this sense just an updated version of more traditional eradication efforts, which have historically sought to wipe out specific kinds of mosquitoes in specific areas using poisonous chemicals.

Nor is the eradication of the mosquito occurring in a vacuum. Organizations like Revive and Restore, flush with Silicon Valley venture capital, are trying to bring back extinct species like the passenger pigeon. As exciting as such initiatives are, and as humanitarian as efforts to stop the spread of Zika may sound, they increasingly normalize genetic engineering.

For scientists, synthetic biology promises nothing short of the resurrection of any extinct species whose genome is known or can be reconstructed from fossil remains. In this process animal species are seen as bundles of genetic information — sequences of letters that can be stored on a computer and then converted into strings of nucleotides that constitute the genes and genomes of the animal.

Synthetic biology, proponents argue, will not only allow us to resurrect extinct life forms but also to engineer new life according to our needs — a potential that has venture capitalists salivating. Intrexon, whose motto is “A Better World Through DNA,” recently added the British mosquito engineering company Oxitec to its portfolio of other genetics firms, including one developing personalized cell and gene therapies.

Technologies like Crispr promise to revolutionize synthetic biology because of their ease of use and cheapness. All one needs to start editing the DNA of any organism under the sun, including human beings, is an RNA fragment, which costs about ten dollars online, and some off-the-shelf chemicals and enzymes that go for thirty dollars or less.

We are completely unprepared for an era in which editing DNA is as easy as editing a Word document. At present there are no legal controls over new technologies such as Crispr and gene drives, no government regulations on editing human DNA, no centralized risk-management inventory of labs where biohazards could be developed and released.

Indeed, synthetic biology is at present dominated by an ideology borrowed from the world of computer hacking: democratize access, the line goes, in order to generalize the knowledge necessary to address destructive behavior. But malicious software is one thing, genetically altered organisms surely another.

Who will decide what organisms are targeted by these new technologies? Who will determine when and if genetically modified organisms are released into the wild? Who will monitor the impact of these organisms? How will we fix things if something goes wrong? And who will be responsible for making things right?

At the moment such questions are exclusively in the hands of scientists, who promise to regulate themselves, and genetic engineering start-up firms, in which the same scientists often have a significant economic stake. Many contemporary scientists, drawing on the 1975 Asilomar Conference at which biologists recommended guidelines for experimentation with genetic technologies, argue for self-regulation.

But this model implicitly allows scientists to push research to the limit, exercising restraint only when such work involves technically defined risks to public health. This approach narrows considerations of risk to the kinds of dangers scientists know best, ensuring that the public must defer to scientists’ biased and often blinkered understanding of risk.

As attractive as the prospect of liquidating the mosquito and halting the advance of Zika using Crispr gene drives may be, we need a moratorium on the use of gene editing. The history of genetically modified crops should serve as a precautionary warning.

Despite enduring concerns about safety, the US public has been explicitly prohibited from knowing about the presence of GMOs in its food supply, largely as a result of the lobbying of powerful corporations like Monsanto.

Studies have shown that upstream scientists — biotechnologists and agricultural technicians — tend to exhibit far less concern about the impact of GMOs than downstream scientists like epidemiologists and environmental toxicologists. There is a long history of broad scientific acceptance of technologies that turned out to have very destructive impacts, from DDT and asbestos to hormone replacement therapy.

Questions concerning the long-term ecological impact of new technologies like Crispr gene drives must be addressed and adequate means of oversight and regulation must be developed. Furthermore, new synthetic biology raises basic questions about the place of science in determining the future in democratic societies.

As such technologies are normalized, the temptation will be strong to use them not just on mosquitoes but also on humans, particularly people afflicted with rare genetic diseases. But the implications of editing out nature’s “mistakes” from the human genome are grave.

How will future generations regard our decisions to meddle with heritable genes? And who should have access to such technologies? We need to have a genuinely inclusive debate about the issues raised by this new technology, one that addresses the ethical, legal, and social implications of gene editing.

Keep It Simple

The allure of genetic engineering — and the potential for profit to be made from such exciting new technology — also diverts attention from other simpler, but nonetheless effective, solutions. Some researchers, for instance, argue that Zika and other similar diseases could be effectively stamped out if communities had access to basic measures like indoor spraying and long-lasting insecticidal nets.

And many of the fears about Zika’s impact on newborns could be allayed if poor women were given adequate access to birth control. These measures would of course entail adequate funding of health workers and infrastructure in poor countries, funding that has been significantly eroded in, for instance, Puerto Rico.

Worse, basic research on diseases that primarily affect poor people has been shockingly underfunded for decades. According to a Lancet article, between 1975 and 1999, only 1.1 percent of new therapeutic medical products were developed for “neglected diseases” such as malaria, dengue, and Zika. In the subsequent decade, only 1 percent of new chemical treatments targeted diseases of the global poor.

If the funding — and political will — had been there, it is quite possible that we would have an effective vaccine against malaria in hand, making discussions about the need to engineer species extinction unnecessary.

In the meantime, perhaps some of the hedge-fund capital that bankrupted Puerto Rico can be used to adequately fund its public health facilities. In its way, this would be a more radical step to eradicating disease than any kind of genetic engineering.