Recommend you read - Guess What Came to Dinner by Louise Anne Gittleman. Parasites are everywhere, Europeans have wormed themselves for years on a regular schedule. Its only in this country that bowel movements and parasites are ignored. I'm assumming that I picked up my tapeworm from undercooked meat. I used to love my steaks rare. You can also get them from fish, but beef and pork tapeworms are more common. However you can pick up the eggs of parasites from unwashed vegetables, so vegetarians aren't always safe.
There are very few competent labs in this country for diagnosis of parasites. The Center for Disease Control will affirm that most local labs are INCOMPETENT. So, don't rely on your local lab or allopathic doc to find any parasites you might be carrying around with you. Perhaps Dr. D. can give you info on reliable labs and doctors in your area.