In an attempt to curb outbreaks of two devastating tropical diseases in the Florida Keys, the FDA is proposing the release of millions of genetically modified mosquitoes into the area. Scientists have bred male mosquitoes with virus gene fragments, so when they mate with the females that bite and spread illness, their offspring will die. This can reduce the mosquito population dramatically, halting the spread of diseases like dengue fever. Local residents aren’t impressed, though: there is no guarantee that only non-biting males will be released, or that no modified DNA will enter a human’s bloodstream if they’re bitten.
As climate change alters normal weather patterns, animals and insects are moving into places where they haven’t ventured before. Common in tropical countries, Aedes aegypti mosquitoes are now venturing into areas of the USA, and they carry two of the most painful insect-borne diseases: dengue, which is also known as “break-bone fever”, and chikungunya, which causes joint pain so severe that sufferers writhe in agony. There is neither a cure nor a vaccine for either disease, so one of the best ways to combat them is to destroy the mosquitoes that carry them. Up until now, insecticides sprayed around Key West have kept most of the biters at bay, but the bugs have now adapted resistances to four of the six chemicals that have previously been used to kill them.
It’s only female mosquitoes that bite—males are only around for breeding purposes—and scientists at the British biofirm Oxitec have found a way to breed male Aedes aegypti with genetic fragments from E. coli bacteria and herpex simplex virus, along with coral and cabbage. This synthetic DNA apparently doesn’t pose much risk to animals, but it does the job of killing mosquito larvae. In experiments conducted by Oxitec in Brazil and the Cayman Islands, millions of modified mosquitoes were released over a period of several months, and they ended up decimating over 95 percent of the targeted insect population. Both countries were so impressed by this result that they’re now hoping for larger-scale operations.
Residents of Florida, however, are more than a little wary about the prospect of having millions of flying, biting GMOs in their neighborhoods. Despite reassurances from Oxitec that the synthetic DNA poses no harm to humans, many Floridians resent being used as “guinea pigs” and are circulating a petition to prevent the mosquitoes’ release. So far, over 140,000 people have signed it.
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