According to an August 18, 2011 report from the US Environmental Protection Agency, at least 10 people across several states have fallen ill with infection from dangerous E. coli, which originates from animal sources such as livestock, as an increasing number of recreational waterways are found to be contaminated with the bacteria.

http://www.foodsafetynews.com/2011/08/dangerous-waters-e-coli-continues-to-threaten-summer-swim-areas/
http://articles.herald-mail.com/2011-08-18/news/29903583_1_coli-bacteria-hemolytic-uremic-syndrome-o157