Fifty years after Stoll published his 'This Wormy World' article, the global prevalence of infections with intestinal nematodes remains virtually unchanged. The main species involved are Ascaris lumbricoides, Trichuris trichiura and hookworms, and there are now approximately one billion infections with each of these, worldwide. Given these large numbers, Man-Suen Chan here focuses on attempting to quantify the disease burden caused by these infections, using a recently formulated method of calculating disability-adjusted life years (DALYs). Using a mathematical model, it is estimated that approximately 70% of this burden can be prevented in high-prevalence communities by treating schoolchildren alone. Programmes targeted at schoolchildren have been shown to be extremely cost-effective, and hence this provides a realistic approach for combating these infections in the future.