It is claimed that GM mosquitoes can contribute to reducing wild mosquito numbers and the incidence of the tropical disease dengue fever but the evidence is yet to be made public – says Dr Helen Wallace

Panama has recently given the go-ahead for open releases of genetically modified mosquitoes in an area to the west of Panama City. The experiments will use GM mosquitoes exported from Europe by the British company Oxitec and are due to start on February 15. The experimental releases are intended to test whether the GM mosquitoes can contribute to reducing wild mosquito numbers and the incidence of the tropical disease dengue fever.

But will local people see a risk assessment that meets European standards so they can weigh up the pros and cons? And will Panamanians and independent scientists be consulted on the risk assessment or will they rely only on information from the company? These questions are important because there are many alleged risks that should be considered and that local people should be told about. Some of these have been acknowledged by the company including in a draft risk assessment provided for planned experiments in the United States, while others are disputed.

The GM mosquitoes have been genetically programmed to die at the larval stage. They are bred in the lab in the presence of an antidote to the genetic killing mechanism – the common antibiotic tetracycline – then vast numbers of males, millions for an experimental release or billions for a commercial one, are released into the environment so they outnumber the wild males and mate with wild females. Because most of the offspring die before adulthood, this is intended to reduce the wild population of Aedes aegypti mosquitoes, which carry the tropical disease dengue fever.

Our concerns include whether numbers of wild mosquitoes in neighbouring areas could increase as a result of releasing millions of GM mosquitoes; whether a different species Aedes albopictus, which also transmits dengue, will move into the area as numbers of Aedes aeypti decrease; whether a reduction in the frequency of biting could increase the incidence of the more serious form of the disease, dengue hemorrhagic fever, as immunity to it is reduced; whether increasing numbers of GM mosquitoes will survive and spread including biting females; and whether new harmful characteristics could be introduced into the wild mosquito population.

The Cartagena Protocol on Biosafety to the Convention on Biological Diversity covers international transports and releases of genetically modified organisms. It is implemented in the European Union by EC regulation 1946/2003, which requires companies exporting GMOs for open release to provide a risk assessment that meets EU standards to the importing country. For releases of GMOs in Europe regulators would consider the company’s risk assessment, ask for further information and produce a scientific opinion for public consultation before any open release could go ahead. For releases of GMOs in Panama, the GM mosquito releases provide an important test of the new national approval process.

The firm conducted its first open release experiments of GM mosquitoes in the Cayman Islands in 2009-10 followed by a smaller experiment in Malaysia in 2010-11. Both countries have halted further releases. Larger-scale experiments started in Brazil in February 2011 and are still ongoing. Despite repeated claims of success made by Oxitec in the press, no results from the Brazil experiments have yet been published in scientific journals. Impacts on dengue fever have not been measured or reported. Experiments in Florida Keys, in America, have been proposed but have not yet been approved by the US Federal Drug Administration.

The company is required to send a risk assessment to Panama that meets European standards but until now this is not open to the public. In our view, the proposed experiments should not go ahead until there has been a full public consultation on the risk assessment and results from Brazil have been published so they are available for independent scientific scrutiny. Local people need to know the pros and cons before they can give their fully informed consent to these experiments.

Dr Helen Wallace is director of the GeneWatch UK campaign group