THE BURNED OVER DISTRICT

Consider the latest plan to combat dengue fever and chikungunya in Florida. Using genetic modification, a British biotech company plans to release male mosquitos with a killer gene that will cause any larvae they spawn to self destruct. On the face of it a perfectly reasonable idea. Male mosquitos suck flowers so they could release a Billion of them without adding a single mosquito bite to the human population. And if the larvae are designed to die it eliminates a large segment of the next generation.So why would people afflicted by the mosquitos and the diseases they carry object?

Reports and statements by Oxitec and its academic and governmental collaborators say trials have reduced mosquitoes in targeted areas by an average of 90 percent. Individual results vary. In two Brazilian villages, reductions were 60 percent to 70 percent, said Danilo Carvalho, a biologist at the University of São Paulo.

But critics say Keys residents are being used as guinea pigs even though the area does not have a dengue problem now. They say questions persist despite numerous meetings with mosquito officials and scientists.

What happens if a person is bitten by a stray female mosquito (Oxitec said a tiny percentage get mixed in the release batch)? Nothing, Oxitec scientists say. What happens to the environment once the mosquitoes are introduced? Nothing, Oxitec scientists say. Who will be liable if something goes wrong with the mosquitoes? Oxitec, if caused by its actions or inaction, a company spokeswoman said.

“Based on the trials conducted, we’re confident that our mosquito is safe for humans, and would do no harm to the environment, as were the regulators who approved its use,” said Chris Creese, Oxitec’s communications director.

In other words, the DNA dies with the mosquito, said Derric Nimmo, Oxitec’s project development manager. “It is very species specific,” Mr. Nimmo added.

Residents say it is difficult to believe information from the company seeking to profit from the project, and their collaborators.

Phil Lounibos, a University of Florida professor of ecology and behavior, said the risks, in general, were “very, very low.” But, he added, “we don’t know all the answers, and Oxitec could do a better job of explaining it.”

Others agree that the danger is minimal. “If there were mosquito genes coming into humans, we would know about it now because there are millions of mosquitoes biting humans every single day,” said Anthony James, a professor of microbiology and molecular genetics at the University of California, Irvine.

Still, residents say, a trial is an experiment.

“This is not the way to protect our community with an unproven and unprecedented experiment in the Florida Keys,” said Meagan Hull, a Key West resident. “The genie will be out of the bottle, and you can’t stuff it back in.”

Some skepticism of science is always necessary, but the deep mistrust displayed in Florida is almost as unhealthy as dengue and chikungunya.