To fight Zika, FDA approves gene-altered mosquitoes

·Senior Editor
A female Aedes aegypti mosquito, known to be a carrier of the Zika virus. (Photo: Andre Penner/AP)
A female Aedes aegypti mosquito, known to be a carrier of the Zika virus. (Photo: Andre Penner/AP)

A promising new approach to fighting the Zika virus through the release of genetically modified mosquitoes won preliminary approval from the Food and Drug Administration Friday.

The agency announced a “final environmental assessment” of a proposed test in Key Haven, Fla., a suburb of Key West, with a population of about 1,000. After reviewing thousands of public comments over the last five months, the FDA concluded there would be “no significant impact” to human health or the environment from the program.

The finding clears a major hurdle for Oxitech, the British biotech company that has developed the mutant mosquitoes, which are already in experimental use in Piracicaba, Brazil. But there is no date set for the Florida test, which would be the first in the U.S.

The Zika virus is spread primarily through the bite of the Aedes aegypti mosquito (as well as sexual contact), and it causes a generally mild illness — but devastating birth defects in some cases when it infects pregnant women. It has been spreading through Latin America and the Caribbean, and recently officials identified more than a dozen cases in southern Florida that appear to have been contracted locally.

The mosquito — which also spreads yellow fever and dengue — is found along a wide swath of the Gulf Coast and parts of the southeastern U.S.

Oxitec has spent years developing a gene that renders mosquitoes essentially unable to reproduce: They can mate, but the offspring inherit a lethal mutation and die before reproducing themselves. To be effective in the field, the plan requires breeding and releasing millions of modified mosquitoes. (Only males — which don’t bite — are released.) In field tests, Oxitec says it has achieved reductions of as much as 90 percent of the local population of Aedes.

The program must still be approved by local and state officials, and many residents of the Keys oppose it on principle, because it involves genetic modification. The board of the Florida Keys Mosquito Control District, which has the final say, voted in June to put the question on the ballot in November. The referendum will be nonbinding, but a majority of the commissioners say they will abide by the results.

The Zika mosquito. (Illustration: Adrian Leung, John Saeki/AFP)
The Zika mosquito. (Illustration: Adrian Leung, John Saeki/AFP)
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