In this July 12, 2015 photo, a boy walks with his father's catch of the day from the Marina da Gloria, in Rio de Janeiro, Brazil. The head of Rio's Infectious Diseases Society said contaminated waters... more 
In this July 12, 2015 photo, a boy walks with his father's catch of the day from the Marina da Gloria, in Rio de Janeiro, Brazil. The head of Rio's Infectious Diseases Society said contaminated waters in beaches and lakes has led to "endemic" public health woes among Brazilians, primarily infectious diarrhea in children. By adolescence, he said, people in Rio have been so exposed to the viruses in the water their bodies build up antibodies. But foreign athletes and tourists won’t have that protection. (AP Photo/Leo Correa) less 
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Associated Press | Photo By Leo Correa
Wed, Jul 29, 2015 11:39 PM EDT