I have had these dental floss like threads 2 to 5 inches long, flat and about 2 mm wide for at least 10 years . I pass one maybe once or twice a week. They look like dental floss and they are very strong. I do not eat anything that would be this long. I have done parasite cleanses but the cleanses have not caused to pass any more of these strings more regularly than normal. I have found pictures like them online but nobody has been able to name them. I wouldn't think a parasite could be this hard to break....its almost more like a thin flat root than a worm. They are much stronger than hair and very hard to break apart.