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GM Mosquito Release in Malaysia Surprises Opponents and Scientists—Again

James Gathany/CDC

Some 6000 transgenic mosquitoes developed to help fight dengue were released in Malaysia on 21 December, according to a statement issued by the country's Institute for Medical Research (IMR) in Kuala Lumpur yesterday. Just like the first releases ever of the mosquitoes, on the Caribbean island of Grand Cayman in 2009 and 2010, the news came as a surprise both to opponents of the insects and to scientists who support them.

The mosquitoes were developed by Oxitec, a U.K. biotech firm that aims to fight dengue by releasing massive numbers of "genetically sterile" male Aedes aegypti mosquitoes. When wild females mate with these transgenic males, there are no viable offspring; the hope is that, as a result, the mosquito populations will collapse.

The news appears to have caught the Malaysian media and public by surprise; many recent news stories reported that the study had been postponed after intense protests. As recently as 17 January, the Consumers' Association of Penang and Sahabat Alam Malaysia, two groups opposing the use of GM insects, called on the National Biosafety Board to revoke its approval for the study. Scientists, too, were under the impression that the work had yet to begin, says medical entomologist Bart Knols of the University of Amsterdam. A 24 January blog post by Mark Benedict, a consultant at the Centers for Disease Control and Prevention in Atlanta who monitors the field closely, mentioned that the Malaysian study was "planned."

Knols worries that surprises such as the releases in Grand Cayman and Malaysia may erode public trust and provide anti-GM groups with ammunition. The two Malaysian groups, for instance, issued a statement yesterday saying they were "shocked ... we condemn the apparently secretive manner in which the trials have been conducted." Helen Wallace of the advocacy group GeneWatch UK says the lack of communication does little to instill confidence in Oxitec.

Oxitec's chief scientific officer, Luke Alphey, confirms that Malaysian media had it wrong. But Alphey says "nobody should have been terribly surprised" by the release. Once all the regulatory hurdles had been overcome, "it seems predictable that the next step would be the actual release," he says. Oxitec did not announce the news itself because that wasn't the company's role, says Alphey: "This was a study by the Malaysian government done in Malaysia. It was up to them to announce it."

Carried out in a remote area of Bentong, a district in the central state of Pahang, the study was designed to test transgenic males' survival and mobility, Alphey says. Some 6000 wild-type males, as well as controls, were released. The study ended on 5 January, after which insecticides were sprayed to kill any remaining mosquitoes, says IMR.

Wallace believes Oxitec is rushing ahead with field trials because it needs to start making money. In a recently posted analysis (pdf), GeneWatch UK claimed that the company is losing some £1.7 million ($2.7 million) per year and needs to pay back a £2.25 million ($3.6 million) loan by 2013. But Alphey says that's not the reason. "We are a for-profit company and finance is not irrelevant," he says. "But anyone who realizes that there are 50 to 100 million cases of dengue every year would feel a sense of urgency."

The study carried out in Grand Cayman last summer was much bigger. There, some 3 million mosquitoes were released to test whether they could actually help bring down the local population. A paper describing the results—an 80% decrease in mosquito numbers—has been submitted to Science, Alphey says.