Florida’s Feud Over Zika-Fighting GMO Mosquitoes

Oxitec’s mosquitoes have been deployed in Brazil, Panama, and Malaysia, but Keys residents are thwarting attempts to try them in the U.S. The idea behind Oxitec’s experiment is that if enough genetically modified male A. aegypti mosquitoes are released into the wild, they’ll track down large numbers of females in those hard-to-find places and mate with them. The eggs that result from any union with an Oxitec mosquito will carry a fatal genetic trait engineered into the father—a “kill switch,” geneticists call it. The next generation of A. aegypti mosquitoes will never survive past the larval stage, never fly, never bite, and never spread disease. No mosquitoes, no Zika. “It takes one or two generations at least to be noticeable,” Lacroix says as he grabs a green fly swatter the size of a tennis racket and starts thwacking away at some of the mosquitoes flying around his head. A. aegypti’s life span ranges from two weeks to a month, so the company will know in a few months if the population is starting to decrease. If it is, Lacroix says, “we can roll out to the rest of the island, drawing down south through the peninsula.” Oxitec charges about $7.50 per person per year in each area it treats. While the price gets cheaper as the A. aegypti population decreases and fewer Oxitec mosquitoes need to be released, the treatments aren’t a short-term prospect: To ensure A. aegypti doesn’t come back, the company continues releasing its mosquitoes on an open-ended basis.