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FDA to Weigh in on Genetically Modified Mosquitoes
Which is a more frightening idea, dengue fever gaining a foothold in the U.S. or releasing millions of genetically modified mosquitoes to stop the disease in its tracks?
Residents of Key West, Florida and Florida health officials have been wrestling with this question for months. Right now, it looks like the FDA will act as arbitrator and have the final say on whether a plan to release millions of genetically modified mosquitoes will actually be carried out.
Dengue fever, sometimes simply called dengue, is a viral disease transmitted to people by Aedes mosquitoes, principally, Aedes aegypti. Once found only in the tropics, the disease has increased 30-fold in the last 50 years, an increase that is expected to continue as the world becomes warmer and the range of Aedes increases. The mosquito's range is limited by how cold an area becomes in winter — freezing temperatures kill its overwintering eggs and larvae.
Alarm Bells Begin Ringing
Dengue fever can be fatal. The World Health Organization calls it the most important mosquito-borne viral disease in the world. The CDC estimates that there are at least 100 million cases worldwide per year. But dengue is virtually unknown in the continental U.S. While Aedes is certainly no stranger to Floridians, until recently the last case of dengue acquired in Florida was in 1934.
Then came the year 2009.
In 2009 there were 27 cases of dengue fever identified in Key West. Blood tests of 240 randomly selected residents indicated that over 5% of the total population may have been infected. This was followed by 66 new cases in 2010. For a community of 25,000 that relies heavily on tourism, this was not good news.
Against this backdrop, Michael Doyle, a mosquito expert formerly with the CDC, became executive director of the Florida Keys Mosquito Control District in July 2011. His orders: cut the budget while killing more mosquitoes, and ensure that if Key West made national headlines, it would be for some other reason than dengue.
Aedes aegypti has been called the stealth bomber of mosquitoes, silent and capable of biting 20 people a day. It prefers unsuspecting people's ankles and legs, and it lives in and around homes, not in the open, where chemicals, larvicide and bacteria might be able to combat it effectively. Something more, Doyle realized, was needed.
Doyle settled on a plan where millions of male mosquitoes would be genetically modified in the lab of the British biotech firm Oxitec, (short for Oxford Insect Technologies) giving them a "suicide gene." They would then be released into the wild, where they would mate and pass this lethal gene onto the next generation of mosquitoes, who would die before reaching adulthood.