"Monsters Inside Me" host talks grossest parasite he's encountered

      |Dan Riskin, host of Animal Planet's "Monsters Inside Me" and co-host of the "Daily Planet" on Discovery Canada, is the author of "Mother Nature is Trying to Kill You: A Lively Tour Through the Dark Side of the Natural World." The book is published by Simon and Schuster, a division of CBS. In this "CBS This Morning" extra, Riskin talks about why humans get grossed-out.