GM mosquito risk assessments ‘deficient’, says review

GM technology may help cut transmission of some diseases transmitted by mosquitoes Copyright: Flickr/eyeweed

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[KUALA LUMPUR] Decisions to release genetically modified (GM) insects into the wild should be made more openly and based on better science, according to a review.

The authors say that, so far, the environmental impact assessments for such releases have been "scientifically deficient", and that without timely, publically available risk assessments the public may turn hostile to the GM mosquitoes before "it is possible to determine what value they possess".

The review, by scientists from the Max Planck Institute for Evolutionary Biology in Germany, comes on the heels of a heated debate about the safety of releasing GM mosquitoes into the wild.

Releases have been spearheaded by a UK-based company, Oxitec, in the Cayman Islands and Malaysia, but have been heavily criticised by some environmental groups.

Proposals for releasing these and other GM insects are now being evaluated in several other countries, including Guatemala, India, Mexico, Panama, the Philippines, Thailand and Vietnam.

But the review asserts that without access to accurate scientific information before releases, it is "naïve to expect that the development of GM insect technologies will progress far" because public opposition is likely to rise.

The regulatory approvals for the first releases in the Cayman Islands, Malaysia, and the United States relied on reports that were not publically available, and on some "questionable pivotal scientific assertions", say the authors.

The review proposes efforts to boost the independent research needed for environmental risk evaluations, and provides a checklist to help anyone evaluate whether a release approval has a good scientific basis.

The first GM mosquito release in the Cayman Islands in 2009 took international scientists by surprise when it was publicised a year later. This was soon followed by a release in Malaysia, and then in Brazil.

The Aedes aegypti mosquitoes are natural vectors for dengue fever. The GM mosquitoes have been engineered to carry the OX513A gene, which shortens their lifespan, in a hope this could cut dengue fever.

But Helen Wallace, executive director of GeneWatch UK, a not-for-profit group that monitors developments in genetic technologies, said there are a lot of uncertainties regarding these GM mosquitoes and their long term effects on the environment.

"More experiments within closed doors and controlled perimeters should have been carried out to measure the risks," she said. "All the information that we have about the results of the trials are from the Oxitec website and there have been no detailed reports published."

The review paper also says regulatory authorities in Malaysia failed to cite published, peer-reviewed studies.

But Oxitec representatives counter that peer-reviewed journals are not always interested in publishing studies that show no surprising effects.

Hadyn Parry, chief executive officer at Oxitec, dismissed the worries and explained the information gap as due to "the peer review process, which can often take a long time" especially if the manuscript is rejected and has to be submitted to another journal.

"This has happened several times with our research as the journals regarded it as not of sufficient interest," Parry said.

The review paper was part of a special section on GM insects, published by PLoS Neglected Tropical Diseases last month (31 January).

The topic has been gathering scholarly attention in the wake of releases in the wild. A special issue of the Asia Pacific Journal of Molecular Biology & Biotechnology was also dedicated to GM mosquitoes in July 2011.  

Link to full paper in PLoS Neglected Tropical Diseases

Link to special section in PLoS Neglected Tropical Diseases

Link to special issue of Asia Pacific Journal of Molecular Biology & Biotechnology


PLoS Neglected Tropical Diseases doi:10.1371/journal.pntd.0001502 (2012)