Every year, hundreds of millions of people swallow a single pink tablet to hold a parasitic worm at bay. In the fishing villages and farm fields of Northern Uganda, that tablet is doing its job. The parasite, though, keeps finding its way back. A 24-week follow up of schoolchildren in one of the country’s most infected regions paints a clear and uncomfortable picture of what “control” actually means once you leave the clinic. This post covers what the study found, why it should worry anyone working on neglected tropical diseases, and what it says about how often we ought to be treating the people most exposed. What schistosomiasis is, and…