Tropical parasitic diseases may lack the headline-grabbing power of bird flu or SARS and they may fail to grab the pharmaceutical industry’s attention. But there is no doubt that they are a massive problem. Schistosomiasis, a disease that many people in Western countries will never have heard of, currently afflicts 3% of the world’s population, a staggering 20 million people, and almost four times that number are at risk.

Schistosomiasis, also known as bilharzia, affects people living across the tropics. It’s caused by parasitic flatworms called blood-flukes, belonging to the genus Schistosoma from which the illness gets its name. It claims the lives of 280,000 people a year and becomes chronic in millions more, causing long-term disability, debilitation and