FDA: No significant impact from test of modified mosquitoes

A field trial releasing genetically modified mosquitoes in the Florida Keys would not harm humans or the environment, according to documents released Friday by the U.S. Food and Drug Administration.

The agency's Center for Veterinary Medicine released a preliminary finding of no significant impact for the field trial on a method that aims to reduce populations of the mosquito that spreads dengue, chikungunya and the Zika virus among humans. The trial is proposed by the British biotech firm Oxitec. The Florida Keys Mosquito Control District wants to test Oxitec's mosquitoes in a small neighborhood north of Key West.

The FDA still needs to review public comments on Oxitec's proposal before deciding whether to approve that trial. Oxitec modifies Aedes aegypti mosquitoes with synthetic DNA to produce offspring that won't survive outside a lab. Oxitec has conducted similar tests in Panama, Brazil and the Cayman Islands.

With or without the test, the district is looking for additional options to kill Aedes aegypti, which it considers a significant and expensive threat. In a statement, executive director Michael Doyle said the district needs to be proactive, and the trial will to determine how efficient Oxitec's mosquitoes are at suppressing the local Aedes population.

"A small trial like this is designed to see if highly reducing the population is possible with this technology here in the Keys. If so, we will then look at larger trial areas," Doyle said.

A residents' group called the Florida Keys Environmental Coalition wants the district to instead try infecting mosquitoes with a bacteria that curbs their ability to transmit disease, arguing that Oxitec's proposal is mostly marketing hype and won't be subject to adequate federal oversight.