http://ircmj.com/?page=article&article_id=64 Syphacia Obvelata or threadworms are similar to the whipworm, in that, they are parasites that affect humans. They are known to have a greater impact on children as it rarely occurs in adults. It doesn't have a long tail like a whipworm and is called a thread worm because it looks like a small whit piece of thread. It spreads quickly when its eggs are digested. It lives and feeds in the human digestive system. http://www.mydr.com.au/kids-teens-health/threadworms-pinworms http://www.nlm.nih.gov/medlineplus/pinworms.html