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article imageGenetically modified mosquitoes released to combat dengue

By Kim I. Hartman     Jan 28, 2011 in Science
Kuala Lumpur - Malaysian scientists have released genetically modified male mosquitoes in Bentong, Pahang, without public approval, in an experiment to fight dengue fever in an uninhabited forested area.
It is the first time Asia has utilized the genetically altered mosquitoes in the wild to curb the spread of dengue. Researchers are hopeful these experiments being conducted or set to begin in a number of countries could lead to a breakthrough in stopping the disease. However critics around the world, including Malaysian environmentalists argue the mutant mosquitoes might wreak havoc on the environment and inadvertent create a strain of uncontrollable mutated mosquitoes, according to a report by the Associated Press.
The Malaysian government-run Institute for Medical Research said it released about 6,000 sterile male lab mosquitoes in an uninhabited forest area in eastern Malaysia on Dec. 21. Another 6,000 unaltered wild male Aedes aegypti mosquitoes were also placed in the area for scientific comparison, it said in a statement to the AP.
Government officials have attempted to calm the fears and address citizen concerns by saying "they are conducting small-scale research and will not rush into any widespread release of mosquitoes," reports CBS News.
CBS reported last fall that Malaysian Prime Minister Najib Razak said "the project was an innovative way to fight dengue after a lack of success in campaigns urging Malaysians to keep neighborhoods free of stagnant water where mosquitoes can breed."
The Consumer Association of Penang (CAP), has opposed the plan to release the genetically modified (GM) mosquitoes, according to Malaysia Today. Tuan Ibrahim, who is the commissioner of Pahang PAS said his office had received many complaints with regards to the releases and said "the ministry should not allow the research without taking into account the views of residents around Bentong."
“The issue of releasing GM Aedes mosquitoes which has sparked international concerns - they should have at least informed the people beforehand and the ministry must be held fully responsible for any implication from the release,” Ibrahim added. He is awaiting a letter of explanation from the ministry.
The institute provided few details of the experiment, but said it was "successfully" concluded Jan. 5, and that all the mosquitoes were killed with insecticide, according to the AP report.
A similar experiment was conducted in the Cayman Islands last year, with over three million set free to be studied. Researchers say the mosquito population decreased by 80% in a 40 acre tract where the GM mosquitoes were released compared with a neighboring location used as a control location where the population increased, reports ABC News.
"This test in the Cayman Islands could be a big step forward," said Andrew Read, a professor of biology and entomology at Pennsylvania State University, who was not involved in the project according to ABC. "Anything that could selectively remove insects transmitting really nasty diseases would be very helpful," he said
Oxitec, a London based company, developed the genetically altered sterile mosquitoes, which are all male, to mate with female mosquitoes in an effort to wipe out the Aedes mosquito population, reports ScienceRay. Dr Luke Alphey, the chief scientist of Oxitec, sterile male Aedes aegypti mosquitoes were given tetracycline in the lab to keep them alive so that they could be breed in large numbers. When these male mosquitoes are released in the wild, they automatically look for female mosquitoes to mate. When the female mosquito produced larvae, most of them die before hatching or create mosquitoes with short lifespans.
Dengue fever, spread only by the females in the mosquito population, is a potentially fatal disease that can cause fever, muscle and joint pain, and hemorrhagic bleeding. The World Health Organization estimates there are at least 50 million cases every year. There is no treatment or vaccine for the fever once bitten by the disease carrying insects.
The number of dengue-linked deaths in Malaysia increased by 52 per cent last year to 134 from 88 deaths in 2009. The AP reported the total dengue infections rose 11 per cent from 2009 to more than 46,000 cases last year.
Universities and researchers in the United States and Australia are conducting research in both similar and alternative ways, including a flightless strain of mosquito, to combat the mosquito-borne diseases including dengue. reports Australia and Vietnam will be conducting more experiments with releases of the genetically modified mosquitoes to be released this year.
Opponents to the experimentation say such plans could leave a vacuum in the ecosystem that is then filled by another insect species, potentially introducing new diseases. If we remove an insect like the mosquito from the ecosystem, we don't know what the impact will be," said Pete Riley, campaign director of GM Freeze, a British non-profit group that opposes genetic modification, according to the ABC report from the Caymans.
Riley said mosquito larvae might be food for other species, which could starve if the larvae disappear. Humans have a patchy track record of interfering with natural ecosystems. "Nature often does just fine controlling its problems until we come along and blunder into it."
So far 'letting nature take its course' in combating mosquito-borne disease has not been completely successful with epidemic-like situations being reported worldwide, including in the United States with reports by Digital Journal of dengue being found in Key West and one reported case in Miami.
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