Global anthelmintic chemotherapy programs: learning from history

May 2001 was a landmark in the control of helminth infections. For the first time, the global community recognized that tools existed to deal with some of the commonest infections on the planet. Yet, many of the concepts had been identified nearly a century before, and subsequently largely forgotten. The lessons of the past have much to impart, and recent work has strengthened the evidence and identified the tools to make global control programs feasible. The challenge will now be to make it happen, and some of the problems ahead are truly massive.