I would argue, that by the time you begin to experience symptoms, you've got an infestation and problems only will get worse. I remember watching an episode of Ripley's Believe or Not in involving an expelled (and preserved) several foot-long tapeworm. The tapeworm was voluntarily ingested so the person would not suffer from "traveler's diarrhea" when going to 3rd world countries. This was back in the 1800's, I think. After the guy got back to England, he took a vermifuge and expelled this very long tapeworm. What the show did not point out is there were probably numerous eggs still in the host and he probably never got rid of all his tapeworms.