NOTE: It's worth viewing this article online as the comments with it include an interesting exchange between Oxitec and the author.
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GM mosquitoes – threat or friend?
Helen Wallace
Public Service Europe, 12 January 2012
http://www.publicserviceeurope.com/article/1342/gm-mosquitoes-threat-or-friend

*Some civil society groups are calling for an immediate halt to any field trials of GM insects and a reassessment of the risks posed by the technology – claim campaigners, while the company involved issues its own rebuttal

Oxitec is a British company, which produces genetically modified insects: it was spun out from Oxford University in 2002. It conducted the world's first open field trials of GM mosquitoes in the Cayman Islands in 2009 and 2010, and has since conducted further open trials in Malaysia and Brazil. This year, the company has plans to release GM mosquitoes in the Florida Keys, and also to begin trials of GM diamond-back moths, which eat cabbages, in Britain. Today, civil society groups in the UK, United States, Malaysia and Brazil have exposed a major flaw in the technology – which will limit its effectiveness and could have serious implications for health and the environment.

We know that GM mosquitoes are intended to reduce the wild population by mating with naturally occurring mosquitoes and producing progeny which don't survive, therefore reducing the population and therefore the transmission of the tropical disease dengue fever. The same technology in agricultural pests is also intended to reduce the population, protecting agricultural produce. The confidential internal document obtained by civil society groups shows that the GM mosquitoes described as "sterile" are, in fact, not sterile and their offspring have a 15 per cent survival rate in the presence of the common antibiotic tetracycline. In the study, the mosquitoes were fed cat food containing chicken contaminated with low levels of tetracycline and many of them were able to reproduce, with their offspring surviving to adulthood.

A redacted version of the document, released to GeneWatch UK under British Freedom of Information laws and to parliament in response to parliamentary questions, shows that the company tried to hide the evidence that its technology will fail to prevent reproduction in the presence of low levels of tetracycline contamination. The evidence regarding the 15 per cent survival rate has been blacked out on grounds of "commercial confidentiality". Oxitec uses tetracycline as a chemical switch to allow it to breed its GM insects in the lab, whilst they are expected to die out in the absence of tetracycline in the environment. But the document reveals a fundamental flaw in this approach because the antibiotic is widely used in agriculture and is present in sewage as well as in industrially-farmed chicken and other meat. Mosquitoes that carry dengue fever are known to breed in environments contaminated with sewage, including septic tanks, and agricultural pests are also likely to be exposed to it.

Failure of GM mosquitoes in the presence of tetracycline contamination could lead to a rebound in cases of tropical disease and biting GM female mosquitoes or other insects might cause unknown impacts on human health, such as allergies. The ecological implications of GM insects surviving and breeding are also unknown. Even in the absence of tetracycline contamination, GM mosquitoes are known to survive in the laboratory at rates of around 3 per cent. In the field, this would translate into large numbers of survivors given that continual releases of millions of GM mosquitoes would be needed to sustain the goals of population suppression.

Civil society groups have called for an immediate halt to any field trials and a re-assessment of the risks posed by the technology. The findings revealed in the document totally undermine existing risk assessments and trust in the public information provided by the company. The new information seriously calls into question any use of the patented RIDL technology, which depends on the use of tetracycline as a chemical switch to allow breeding of GM insects in the lab. The company has previously been widely criticised for putting its commercial interests ahead of public and environmental safety. Its first releases of GM mosquitoes took place controversially in the Cayman Islands, where there is no biosafety law or regulation.

Staff have been closely involved in developing risk assessment guidelines for GM insects worldwide, leading to concerns about lack of independent scrutiny and conflict of interest. The discovery of the GM mosquitoes' high survival rate also highlights underlying problems with the use of developing countries as test grounds for risky new technologies. In addition to the trials that have taken place in Malaysia and Brazil – other countries where releases of GM mosquitoes have been proposed include Panama, India, Singapore, Thailand, Vietnam, the Philippines, Costa Rica and Trinidad & Tobago.

Dr Helen Wallace is director of the GeneWatch UK campaign Group