In the north of Burkina Faso, not far to the east of one of the best-known backpacker destinations in West Africa, the Bandiagara Escarpment in Mali, lies the town of Koumbri. It was one of the places where the Burkina Ministry of Health began a mass campaign five years ago to treat parasitic worms. One of the beneficiaries, Aboubacar, then an eight-year-old boy, told health workers he felt perpetually tired and ill and had noticed blood in his urine. After taking a few pills, he felt better, started to play soccer again, and began focusing on his schoolwork and doing better academically.