The Fink Family Scholarship
August 11, 2016
GENETICALLY ENGINEERED MOSQUITOS
FDA issues Finding of No Significant Impact for Oxitec's genetically engineered mosquitos; anti-Zika trials scheduled for Florida
On August 5, the FDA released a final environmental assessment for genetically engineered (GE) mosquitos produced by the British biotechnology firm, Oxitec. The assessment included a Finding of No Significant Impact (FONSI) for a proposed field trial of the mosquitos in Florida. The Oxitec mosquito strain, OX513A, consists of male Aedes aegypti mosquitos with a self-limiting gene modification, who mate with wild females and produce offspring incapable of survival. Aedes aegypti strains carry the Zika virus, and reductions in their populations is key to controlling spread of the virus in the US.
The modified gene produces a protein, tTAV (tetracycline repressible activator variant), which blocks expression of other mosquito genes, thus rendering the mosquito incapable of survival. Larvae for male mosquitos, which do not bite, are separated from female larvae, and grown in an aqueous environment containing tetracycline, which suppresses production of tTAV. Offspring in the wild, however, will not be exposed to sufficient levels of tetracycline and will die. Neither the tTAV protein nor other proteins produced in the nonviable offspring are toxic, and thus animals consuming the offspring are not affected.
Trials of GE mosquitos in Piracicaba, Brazil, demonstrated significant reductions in populations of wild-type Aedes aegypti strains, and a 91% drop in cases of dengue fever, according to an Oxitec press release in mid-July. The FDA's FONSI will allow trials to begin in Key Haven, FL, but large-scale marketing of the organism will require further FDA review. [USDHHS, FDA. FDA releases final environmental assessment for genetically engineered mosquito; 2016 Aug 5; http://bit.ly/1McvLMg; Oxitec Ltd., Technology; http://bit.ly/2aMKVeF, accessed 11 Aug 2016]
2016 DPLXXVII Seminar
November 10-13, 2016