There's nothing quite like a deep dive into the shallow, vomitous puddles of children's splash pads. Even toeing the edge is enough to have one longing for the unsettling warmth of a kiddie pool. But the brave souls at the Centers for Disease Control and Prevention have done it, wading into 25 years' worth of records on gastrointestinal outbreaks linked to the wellsprings of fecal pathogens.