Genetically Modified Mosquitoes Could Be an Important Tool in the Fight against Disease
By Mark Q. Benedict
Readers of Scientific American will appreciate the high failure rate of what seem to be promising innovations. The much ballyhooed "Ginger" was going to change the world and the way our cities are built. Hadn't multitudes of celebrities gushed over Ginger and invested? I could not wait to find out what something given such a sexy code name could be. A new energy source? A new concept for a computing interface? A self-healing material? You may have shared my disappointment when the mysterious Ginger turned out to be a rather clunky, unattractive but easily operated scooter named the Segway. My initial response that Ginger was not going to change the world has thus far been correct. Segways have indeed created a niche populated by policemen and tourists, and it has stimulated the production of other cheaper vehicles that are used in much the same way. They were not the game-changer that was anticipated. I guess I'll wait for Mary Ann.
I was also among those who hopefully (and skeptically) followed cold fusion in 1989. Against the original claims, however, excess heat was not measured in subsequent experiments. The claims didn't hold up. Yes, there are still folks pursuing the idea, and I would be the last to discourage them. The world could use endless clean energy in such a concentrated form.
We can safely say that controlling mosquito populations by releasing genetically modified (GM) mosquitoes is not another cold fusion of innovation, but it may be a Ginger. For the sake of those who need help, I hope not.
Current technologies we use against mosquitoes simply are not adequate: existing measures are losing the war. None are easy and even fewer are affordable for vulnerable individuals and governments charged with mosquito control. They do not fully protect, and their use entails direct risks to human health and the environment. So the choice of implementing GM mosquitoes is not a choice of no risk versus risk, it is a matter of choosing the least risky among all existing choices in a war against very real continuing disease risk.
Genetically modified mosquitoes are not the only innovative solution being tested in this war: resistance-proof insecticides, anti-mosquito fungi, bioprospecting for drugs and repellents, biopesticides, better education programs and new traps are in play. There is room for all of these, but all of these entail risks, not least of which is diversion of limited resources to little effect.
In this context, we must consider whether releasing sexually sterile GM mosquitoes is safe. History says "yes." Sterile insects have been safely used for decades. Target pests have never become established due to failure of sterility, and sterile insects are often used to prevent the establishment of insects where they do not occur. The sterile mosquito technology is being tested specifically because it is the safest possible means to begin to explore their potential. It is difficult to argue that use of the most common measure—nonspecific insecticides—is a more desirable option.
Novel technologies are always in the midst of a withering process that subjects them to the brutal stresses of real-world trials, and implementation of genetically modified mosquitoes will fly or fail based quite simply on whether they work. And by "work," I include their effects on the environment and acceptability by those at risk. Picking winners among all the options is impossible. We simply know too little of their possibilities or the future to predict their success in myriad disease transmission settings.
Regulatory structures are important controls on the implementation of innovation. They guide safe use and fair testing. As the feature indicates, these are coalescing contemporaneously with the development of genetically modified mosquitoes, but they are not being developed in a vacuum. New guidelines largely reflect ethical and safe practices that are already widely acknowledged and codified. Any effort to release genetically modified mosquitoes without proper considerations for such existing law, ethics and safety imperils the entire field, so motivation among those conducting trials to stay above board is high. The community developing GM mosquito technology is always looking over its shoulder at the India experience (in 1974, scientists studying the genetic modification of insects for disease control were accused of conducting secret biowarfare research) and is in no mood to repeat it.
Just as the world is a beautiful mosaic of cultures, it is a mosaic of attitudes toward, and regulation of, genetically modified organisms. This is a natural outgrowth of perspectives toward the natural world, the role of science and even religious beliefs. Therefore, regulation will differ as determined by law and treaty of sovereign countries. Whereas many countries will adopt similar standards rather than developing them de novo, the variety of perspectives dictates that in respect for others we must accept a variety of regulatory solutions. Similarly, community engagement must fit the affected people. What may be sufficient engagement for my community (which is accustomed to eating GM foods and having GM crops planted in fields we see every day) may not fit yours. This is natural and should be welcomed.
GM mosquito technology must be evaluated as a complement to existing control measures. Will it entail the risks that some fear? This should be carefully determined in small trials. Will it be too expensive? That is for those considering it to assess based on experience, their economies and the effects of release. Will it cause environmental damage that can be avoided with other technologies? Let's find out, one cautious small step at a time and in comparison with all the alternatives. But there is no scientific basis for the assertion that sterile insect technology will get out of control and should not be tested.
Although I am among those with hopes that GM mosquitoes will improve human health with minimal environmental effects, it is simply too soon to tell. Because there is no well-financed advocacy machine to push them against demand, GM mosquitoes will have to stand on their own merits in the real world of human diseases. That is the battle which they deserve a chance to fight.
Mark Q. Benedict is currently a Marie Curie Fellow at the University of Perugia, Italy. His professional activities include developing technology for genetic control of mosquitoes, biosafety guidelines and mosquito mass production equipment and facilities. He obtained his PhD and BS at the University of Florida.
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