As far as security details go, mine is pretty unflappable. They are seldom fazed by unruly crowds or post-conflict hotspots. But travelling in East Africa one day last year, I stepped into a swarm of mosquitoes. From the expressions on their faces, I realised that close protection was no match for this unarmed threat the size of a speck. Malaria is a relentless killer. In the time it takes to read this article, six more children will die of the disease. Each year, as many as half a billion people catch malaria. More than a million die. Experts say that malaria slows economic growth in Africa by up to 1.3 per cent a year, holding back development and costing tens of billions of dollars in lost productivity. In countries where the disease is particularly acute, it's not unusual for malaria to consume as much as 40 per cent of government health budgets. This has a crippling effect on social health, welfare and development. This is unacceptable