I am on my 3rd flush...I have been passing exactly what you describe since my 2nd ES this evening. I actually have passed nearly 30. They are Sooo gross.
I have a post a few down asking the same question...but I cannot seem to get an answer. There is a photo in the images gallery under Parasites, forum 1.
I have been tearing through the internet also trying to figure this out. I want to know what kills the little buggers.