In the five months before I originally became ill with ME in 1991, I briefly "swam" a few times in the Potomac River in Alexandria, Virginia. The swims were both intentional and unintentional, as I was learning to row a rowing shell, and we were required to demonstrate that we could climb back into our boats. Since then, I have learned that that stretch of river is now (25 years later) highly polluted, and presumably was when I became ill. Raw sewage dumps into the river following storms when the city's storm sewers are overloaded. My first symptoms included a brief gastrointestinal illness. Has anyone else ever wondered whether a pathogen caused by contamination might have triggered their illness? My hypothesis would seem stronger if I'd become ill immediately following an immersion in the river. In fact, I became ill following an intense exercise regime over the five-month period, interspersed with perhaps two or three spills into the river.