“I don’t think most people would have any qualms about totally eliminating them,” says Professor Hilary Ranson, head of vector biology at the Liverpool School of Tropical Medicine. “I spend most of my time trying to keep them alive and study them, but that’s in order to try to kill them. Ultimately I wouldn’t be too sentimental.” Professor Steve Lindsay, a public-health entomologist at the University of Durham agrees: “I have no problem with taking out the mosquito.”
A species can be eradicated by altering the genetic code of males in captivity so that they will only be able to produce sterile offspring, then releasing them into the wild to mate with unsuspecting females, rendering the next generation barren. Oxitec, a British company that has pioneered this kind of genetic modification, has been conducting trials since 2009, and has a production facility in Campinas, Brazil. And it is not alone.
“It really has been a gamechanger,” says Andrea Crisanti, professor of molecular parasitology at Imperial College London. “We are able to modify the gene with unprecedented precision and flexibility.” Crisanti, a leading expert in the field, has focused his own work on a similar mechanism that fights the malaria-carrying Anopheles gambiae, but he says that it could be exported to other species as well. “There are lots of advantages. If it doesn’t work, nobody has to worry: if they can’t breed, the GM is selected out. If it works, in theory you have total extinction. And if people are concerned about that, you can keep some in the laboratory and reintroduce them. So it is totally reversible.” He gives a small laugh, and sounds freshly amazed at the power of the technology at his fingertips. “We can edit nature,” he says. “This is an incredible new development.”