When we think of death and destruction, our minds likely fill with images of fires, tsunamis, car accidents, and nuclear disasters. But in fact, the deadliest threat to the human race is none of these things. As Michael Specter writes in his new article for the New Yorker, “mosquitoes have been responsible for half the deaths in human history.” Malaria, a disease spread by the Anopheles mosquito, caused up to one million deaths in Africa in 2008.
Up until now, our main ways of combating mosquitoes involved avoidance and swatting. But a British company is trying something different: the genetic modification of the mosquitoes themselves.
Biotechnology company Oxitec has developed a method to modify the genetic structure of the Aedes aegypti mosquito, essentially transforming it into a mutant capable of destroying its own species. Eggs fertilized by genetically modified males will hatch normally, but soon after, and well before the new mosquitoes can fly, the fatal genes prevail, killing them all. The Aedes mosquito is responsible for Dengue fever, a disease that infects 50-60 million people each year, as well as yellow fever.
"[Dengue] is a tremendous beneficiary of globalization," Specter says. One of the favorite breeding grounds for Aedes aegypti mosquitos is the inside of an automobile tire, of which there are billions exported around the world.
Specter sees this new aggressive attempt to kill off mosquitoes as an excellent way to disrupt the species and bring down the number of Dengue infections. "The result would be that the more you mate these lab-bred mosquitos with wild females, the more the eggs would be impotent and die, and not be able to carry Dengue," Specter says. Nicknamed "break-bone fever," the disease causes extreme pain, does not have a cure, and kills thousands of people every year.
One of the risks of genetically modifying plants or animals is a potential disruption of the food chain, which could bring unforeseen consequences down the road if the program were implemented on a large scale. However, Specter believes that North and South America would do just fine without the Aedes aegypti, which is originally an invasive species that came over from Africa aboard ships a couple hundred years ago.
"They could be gone, because that's really not enough time to make an evolutionary impact anywhere," he says. Mark Q. Benedict, an entomologist at the University of Perugia, says “it’s important to remember we’re already trying to wipe this species out, and for good reason. The risk involved in eliminating them is very, very small. The risk in letting them multiply is enormous.”