You take a drug that kills the tapeworm. You have to kill it inside the body because the tapeworm's head or scolex uses multiple hooks to attach to the wall of the small intestine. Once it's dead, the head comes away and the whole worm is passed out of the body.
With live tapeworms, the segments containing eggs break off and you can get chains of quite a few segments which still squirm around, even though they're not attached to the head anymore. The biggest I've seen was about 2 feet and even without the head I went into the walk in incubator with a whip and a chair.
Once a patient has been treated every single poo is examined by some poor sod in a lab until the head is found. Bearingin mind that the head is small and the poo is big, this is one of the most odious and odoriferous jobs I've ever had to do. It's like looking for a needle in a haystack. If the drug treatment hasn't been effective and the head alone is alive and still inside, it will regenerate. The segments themselves won't regenerate.
Recently on TV, a chap made a documentary about growing his own tapeworm and we got to follow the process from ingestion to it's final demise. He named it Rory, caught it in a seive, laid it out in his garden and measured it - it was about 25 foot long IIRC. He would have kept it longer, but he was getting married and his bride to be didn't want to share her honeymoon bed with Rory.
™ Version 4.2
