An Ohio teen recently died after contracting a brain infection from an amoeba, likely while on a whitewater rafting trip in North Carolina. Before you freak out and swear off water sports for good, know that contracting the fatal infection is super rare. In the last decade, just 37 cases were reported in the U.S. What's more, the amoeba isn't found in salt water, so oceans are a-OK. The majority of cases in the U.S. have been linked to swimming in warm freshwater (think lakes and rivers) in the Southern states, the CDC says. But again—there's really no need to work yourself into a frenzy.