Male mosquitoes have been modified so any young they sire quickly die (Image: Oxitec)
The insect assassins have been launched. Millions of genetically modified mosquitoes have descended on the Brazilian city of Piracicaba in the battle against dengue and a test in Florida is also in prospect.
The GM mosquitoes are all male, and when they mate with native females, they pass on a gene to offspring that causes the larvae to die before they mature.
The plan is to flood the area with GM mozzies to outnumber native males, gradually whittling down the numbers of dengue-transmitting mosquitoes.
The GM mosquitoes were designed by Oxitec of Abingdon, UK, and are bred en masse in a factory in Campinas, Brazil. The firm has a permit to commercialise and release the mozzies anywhere in Brazil.
Oxitec is also waiting for a permission from the US Food and Drug Administration (FDA) to test the mosquitoes on Key Haven in the Florida Keys.
Since April, 6 million GM mozzies have been released in the suburb of Piracicaba that is worst infested by Aedes aegypti, a mosquito that spreads the dengue fever virus.
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