Genetically modified mosquitoes, designed to fight spread of dengue fever

Dengue is a scourge of a disease. It’s spread by mosquitos and kills more than a million people every year.

The disease is carried by mosquitoes, mostly the Aedes aegypti. Found in urban areas, Ae. aegypti has proven a particularly difficult mosquito species to control—it has developed a resistance to common insecticides and, because it bites during the day, bed nets are no protection against it. But now Brazilian health officials are running a pilot program using genetically modified mosquitoes to breed the population to death. The mosquitoes are the invention of British biotech company Oxitec, and they’ve had a gene inserted into them that kills them. In the lab, the mosquitoes can be fed a sort of antidote: a supplement that keeps them alive until it’s time to release them. Once they’re released, the clock starts ticking.

Oxitec’s mosquito-suppression solution consists of releasing the modified male mosquitoes into the wild—male mosquitoes don’t bite; it’s the females who do. The Oxitec males mate with female mosquitoes and create progeny that also have the lethal gene. Without the supplement, those progeny die. “By applying the Oxitec Control Programme to an area,” the company’s website says, “the mosquito population in that area can be dramatically reduced or eliminated.”

Remarkable. Here’s hoping this works, with no hidden consequences.