A discovery by British scientists has transformed the fight against the world's deadliest disease. You wait for years for a breakthrough in the battle against malaria, and then two come along in two weeks. But the advance announced yesterday by scientists at the Wellcome Trust Sanger Institute in Cambridge is potentially far more significant than last month's news of an experimental vaccine made by GlaxoSmithKline (and part-funded by Bill Gates), which showed partial success in early clinical trials. Scientists involved in those trials emphasised that the vaccine would only be able to contribute to the control of malaria.