In the Florida Keys, the local mosquito control agency has just approved the release of 750 million genetically engineered mosquitoes. The test, which is likely to begin in 2021, will be the first time that mosquitoes—designed to be “self-limiting,” meaning that they’ll breed offspring that can’t survive—will be used in the United States.
Oxitec, the U.K.-based company that engineered the mosquitoes, plans to place boxes filled with mosquito eggs in the area, releasing male mosquitoes bred with the self-limiting gene. When they breed with female mosquitoes, female offspring won’t survive. Because only female mosquitoes bite humans, this can help stop the spread of disease. The species they’re targeting is the Aedes aegypti or “yellow fever” mosquito, an invasive species that transmits diseases such as dengue, chikungunya, and Zika.
“With repeated releases over a number of weeks, the population of females gradually reduces,” says Kevin Gorman, Oxitec’s head of global field operations. “And we end up with vector control. It’s taking away that vector that is intended to reduce the incidence of disease.”
In previous tests in other countries including Brazil, the company says that the process has worked to dramatically shrink populations. “We’ve had multiyear programs giving over 80% control in every single year,” he says. “And that far exceeds typically what people get trying to control Aedes aegypti with chemicals, because aegypti is very resistant. It’s not usually present in super-high numbers. So it can be difficult to actually reach.”