'Lame' mosquitoes to stop dengue

The dengue virus is spread by infected female Aedes aegypti mosquitoes Scientists are breeding a genetically altered strain of mosquito in an effort to curb the spread of dengue fever. The dengue virus is spread by the bite of infected female mosquitoes and there is no vaccine or treatment. Experts say the illness affects up to 100 million people a year and threatens over a third of the world's population. Scientists hope their genetically altered males will mate with females to create female offspring that will inherit a gene limiting wing growth. The study is published in Proceedings of the National Academy of Sciences. The scientists say their approach offers a safe, efficient alternative to harmful insecticides and could be used to stop other diseases spread by mosquitoes, like malaria.  Current dengue control methods are not sufficiently effective, and new ones are urgently needed  Researcher Professor Anthony James They estimate that if released, the new breed could sustainably suppress the native mosquito population in six to nine months. Researcher Professor Anthony James, of the University of California, Irvine, said: "Current dengue control methods are not sufficiently effective, and new ones are urgently needed. "Controlling the mosquito that transmits this virus could significantly reduce human morbidity and mortality." Grounded The plan is to release genetically-altered male mosquitoes who will mate with wild females and pass on their genes. The scientists have shown that females of the next generation who inherit the gene are unable to fly because it interrupts normal wing growth. Male carriers of the gene remain unaffected. Lead researcher Luke Alphey, of the University of Oxford and his own spin-out company Oxitec Ltd, said the approach was highly targeted. "The technology is completely species-specific, as the released males will mate only with females of the same species. "Another attractive feature of this method is that it's egalitarian - all people in the treated areas are equally protected, regardless of their wealth, power or education." Dr Hilary Ranson, of the Liverpool School of Hygiene and Tropical Medicine, said the work was a major step forward. "This is a significant advance. It will be logistically challenging to make and release enough of the male mosquitoes and it's not going to be cheap. But it can be done with the right resources." She said dengue fever was an ideal disease to tackle in this way because it is spread by only a couple of species of mosquito. She said malaria would be harder to beat because of the variety of mosquitoes carrying the disease