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Tuesday, Oct 7, 2008
Bioengineered insects could help defeat malaria -- or they could turn out to be Frankenbugs, wreaking havoc on our ecosystem.
Jan 7, 2004 | It is winter in America and mosquito season has long since passed. But the threat posed by mosquito-borne illnesses -- malaria, dengue fever, yellow fever, West Nile virus -- is still serious, and growing, across the world. So even as low temperatures keep these insects from breeding in their beloved boggy puddles, inside entomology departments across the country, green-eyed transgenic mosquitoes are swarming -- bioengineered skeeters that represent the front line of the rush to introduce genetically modified creatures into the natural environment.
In 1897, British scientist Ronald Ross discovered that malaria was spread, or "vectored" by mosquitoes. He was also the first to propose reducing or eliminating the world's mosquito population as a way of controlling the disease. But it wasn't until early WWII forays into chemical warfare -- leading to the discovery of insecticides ferocious enough to take on the insects -- that such an idea became truly feasible.
Since that point, the fight against mosquito-vectored ailments has been a chemical battle. Scientists developed drugs that were very useful against the diseases, and insecticides that were very useful against the mosquitoes that transmitted these diseases. And for a time it looked as though we were winning the fight. Unfortunately, in the past 30 years the rules of our chemical battle have changed. Mother Nature interceded and evolution occurred. The insects are now resistant to the pesticides, and the diseases are now resistant to the drugs.
A number of these diseases are considered the deadliest on earth. Today, principally in Africa and Asia, dengue fever annually infects more than 50 million people and kills 500,000. Malaria infects about 400 million and manages to kill more than a million. More disturbingly, the combination of pesticide and drug immunities along with the rise of global transportation and current climate changes has resulted in mosquito-vectored ailments appearing in places where they have not been seen before. Last year in the United States, dengue appeared for the second time in Hawaii and the first time in the Gulf States, and last summer there were 4,000 reported cases of West Nile and 300 deaths. Malaria has so far failed to make serious new inroads into the United States, but in the slightly purple words of the Malaria Foundation International, "a plague is coming back and we have only ourselves to blame."
To address these concerns, during the past 15 years scientists have been trying to move beyond the chemical paradigm and to a genetic one. The dream has been to build a genetically modified insect, a transgenic mosquito, that is unable to transmit such diseases. This new insect would then be introduced in the wild, thus supplanting malaria carriers with a harmless imposter. Seven teams, both in America and in Europe, demonstrating a collaborative spirit not often found in modern science, have been at work on the project. In recent months they have succeeded in achieving major breakthroughs.
It is now possible to walk into any number of molecular biology labs and peer through a microscope at a mosquito unlike any other in history. The magnified insect shows a feature not found in the wild: a pair of bright, fluorescent green eyes -- the telltale sign of successful genetic modification. These eyes are proof that one of the most scientifically advanced cures for disease ever conceived is feasible. They are also proof that, if we are not exceptionally careful as this research progresses, something could go horribly wrong. We could do irreparable damage to the ecosystem or, worse, create new, more devastating ailments currently unknown to science. One thing is certain: The bioengineered mosquito hangs precariously off the cutting edge of genetic research. How we proceed is likely to set standards for how we mold our world at a time when such moldings are both probable and perhaps practical.
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