>Actually, according to CDC healthy swimming spokesperson and epidemiologist Michele Hlavsa, it’s poop. She tells LiveScience’s Rachael Rettner that people with diarrhea can spread a filter and chorine-resistant Cryptosporidium, a parasite that is the leading cause of waterborne disease.

I love swimming and this article has just disturbed me so much, I'm not sure I'll be going to the swimming pool in the near future.