ScienceThomson Reuters A technician from Oxitec inspects larvae of Aedes aegypti mosquitoes in Campinas, Brazil.
Public-health officials are doing everything in their power (and budget) to prevent infectious diseases like Zika, yellow fever, and dengue from spreading.
But the bugs that transmit those diseases, specifically the Aedes Aegypti mosquito, aren't entirely easy to control.
So as an alternative to insecticides or other mosquito-killing tactics, a company called Oxitec has genetically engineered mosquitoes that aim to cut down on the natural mosquito population.
So what could possibly go wrong with unleashing a whole bunch of genetically engineered mosquitoes on a population?
The worst-case scenario, according to Oxitec CEO Hadyn Parry: "That it doesn't work."
Oxitec's mosquitoes are engineered to limit the population. They only make male mosquitoes since the female mosquitoes are the ones that bite. Those engineered bugs mate with female mosquitoes and pass on a gene that kills little baby mosquitoes before they ever mature into adults.
As the modified bugs breed more and more, the mosquito population shrinks overall. In a pilot trial, the bugs were able to cut down the mosquito population by 90%.
"If you think about our mosquito, it's the same as a wild one," Parry explained. That the Oxitec mosquitoes pass on a gene that stunts the survival of their offspring is "the only difference," he said. It shouldn't have any impact on human health (these ones don't bite), nor on the environment. "If you release mosquitoes, and it doesn't work ... then they're the same as a normal mosquito."
So if that lethal gene doesn't work, the worst that could happen is that it doesn't do the job of cutting down on the population. But, Parry said, that doesn't mean that the mosquito population will grow because of an influx of male mosquitoes. Female mosquitoes really only have time to mate once to get all they need to fertilize eggs, so it likely wouldn't produce more because there's more male bugs around.
Parry clearly has some skin in the game, but he's not the only one who's not worried about the unintended consequences of messing with genes.
Chelsea Smartt, an associate professor at the University of Florida, argued in The New York Times that the problem is not about safety but efficacy. "The problem with this idea is not that there is a great risk of humans getting transgenic DNA, although some unforeseen risk may be present, but whether the measure to control mosquitoes actually works in the wild in a sustainable way," she wrote.
If the lethal gene doesn't work, Parry said, the bugs all carry markers so they're able to track it. So if the males were able to produce babies that lived past a certain point, Oxitec would be able to identify those bugs and stop releasing more until they figure out what went wrong.
So rest easy knowing that an out-of-control mutant-mosquito population wasn't in the running for "worst-case scenario."