This video is unavailable because we were unable to load a message from our sponsors. If you are using ad-blocking software, please disable it and reload the page. Embed Code Restart Playing WATCH MORE VIDEOS FROM THIS EPISODE > A 2013 study conducted by the CDC found that more than half of public pools in the U.S. tested positive for E. coli. The Doctors and environmental scientist Jen Ervast share tips to help swimmers prevent sickness from contaminated pool water. ShareTweet