I'm guessing it's Ascaris lumbricoides. I learned about it in Parasitology classes. And I've seen it in bear feces.
It will burrow into any part of the body. I remember hearing of some socialite that had a huge on crawl out her nose during a fancy event.
I've seen them 6-8 inches long.
My guess is that a lot of people in the U.S. have these but they get overlooked because we live in a "Modern Society" that has sanitation. It will become more of a problem as more of the 3rd world moves here and brings their illnesses with them.