Researchers reported initial signs of success Sunday from the first release into the environment of mosquitoes engineered to pass a lethal gene to their offspring, killing them before they reach adulthood.
The research is arousing concern about possible unintended effects on public health and the environment, because once genetically modified insects are released, they cannot be recalled.
Authorities in the Florida Keys, which in 2009 experienced its first cases of dengue fever in decades, hope to conduct an open-air test of the modified mosquitoes as early as December, pending approval from the federal Agriculture Department.
Critics say that Oxitec, the British biotechnology company that developed the dengue- fighting mosquito, has rushed into field testing without sufficient review and public consultation, sometimes in countries with weak regulations.
The first release, discussed in a scientific paper published online Sunday by the journal Nature Biotechnology, took place in the Cayman Islands in 2009 and caught the scientific community by surprise. Oxitec has subsequently released the modified mosquitoes in Malaysia and Brazil.
