For more than a century, people have battled malaria by fighting its carrier, the indomitable mosquito. But last month, scientists at the University of Arizona found a way to turn this blood-sucking enemy into a potential ally. They performed the trick by altering the bug’s DNA, making it 100 percent resistant to the disease and shortening its life span enough to stymie the growth of malarial parasites. The next step would be to give this malaria--proof insect an evolutionary edge and release it into the wild, where it can conquer the world’s existing mosquito species.
It could take more than a decade before this idea is ready to be implemented. But the hand--wringing has already begun. Scientists have never played God in such a way, replacing a natural species with one of their own creation. “We don’t know the long-term effects,” says Eric Hoffman, a campaigner at Friends of the Earth, which opposes genetically modified organisms. The World Health Organization intends to devise rules for testing genetically modified mosquitoes to ensure, among other things, that the bug’s altered DNA doesn’t make it a better carrier of other diseases.
In the meantime, scientists are pushing forward. Because mosquitoes are showing signs of developing resistance to insecticides—and malaria continues to kill about a million people a year—a genetic approach may be needed. “Hopefully,” says Michael Riehle, an entomologist who led the University of Arizona research, “the benefits will outweigh the risks.”