Dengue fever—a brutal virus that infects as many as 100 million people each year—has an unusual new enemy designed to stop the spread of the disease: genetically modified mosquitoes.
Introduced in the Cayman Islands and Brazil, the GM mosquitoes were released in late 2010 in Malayasia—one of the hardest hit regions for dengue fever—by scientists from the Institute for Medical Research. Six thousand GM mosquitoes developed by the U.K. company, Oxitec, were released into Malaysia's forests in a highly experimental approach to help prevent the widespread illness.
The Oxitec mosquitoes—sterilized males of the Aedes aegypti species—were engineered to actually carry a lethal gene that would kill any offspring before they became capable of reproducing. The females breed a singular time in their lives, so the modified males were an attempt to reduce the number of offspring carrying the dengue virus.
In the current issue of Scientific American, Hellen Wallace, the director of GeneWatch UK, writes that there are a number of issues that should be addressed before any GM insects are released including "adverse effects associated with the flow of genes into the wild population; the interactions of the GM insect with target and nontarget organisms; the impact on agricultural management practices and on management measures to control insects that are vectors for diseases; and a variety of potential effects on human health."
Among the human health risks are allergies and irritation, immune malfunction, as well as the potential for other viruses to become more potent and cause additional health risks for exposed humans.
Dengue fever causes severe headaches, fever, fatigue, nausea and vomiting to its victims, but does not typically lead to death. There is no cure.
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