I saw a biology professor give a colloquim on human parasites.... it was by far the grossest collection of images I had ever seen. Pictures showing that no part of the human body is immune to hosting some other organism.... I think the worst was a picture of this kid (10 yr old or so) that had a massive colony of worms in his GI tract. The pic showed what otherwise looked like a wad of spaghetti coming out of this kids butt. YUCK!