THE country has seen an unprecedented number of dengue cases over the summer and the authorities have proved virtually ineffective in tackling the crisis. In this context, the creation of genetically engineered mosquitoes appears, at first glance, a promising piece of research. The British biotechnology company Oxitec has created Aedes aegypti mosquitoes, the male variety of which contains a fatal gene. When these mosquitoes are released into the wild, they will live long enough to mate but their progeny will die before reaching adulthood, diluting and eventually reducing mosquito populations. The first such release, discussed in a scientific paper published on Sunday, took place in 2009 in the Cayman Islands. An open-air test is now to be conducted in Florida Keys, pending approval from the US Agriculture Department. The project’s proponents believe that this is a more ecologi-cally friendly method of mosquito control than insecticides.

However, even supporters of the research are concerned that the public’s reaction to this development may be in line with its reluctance to  accept genetically modified crops. Once the mosquitoes are released, there is no way of recalling them, and negative environmental or human/animal health consequences in the long term cannot be ruled out. Mosquitoes could evolve a resistance to the lethal gene. Also, there is the chance of error in the sorting of mosquitoes, which is done by hand: only males can be released since it is the females that bite and transmit disease. If millions of modified mosquitoes are released, even a small percentage of females among them could lead to a increase in the spread of disease. Oxitec has been accused of rushing into the field test stage without sufficient review, and in countries with weak regulations governing public health. It should proceed with caution, for playing with nature can lead to unintended consequences.