That suggests that your fecal material is hanging around in your colon for WAY TOO long. (3 days to get to maturity for worms, who are somehow surviving with zero oxygen).
And then, how do the lil' b*stards make it from the large intestine all the way back up to the small intestine again? I mean, that's called swimming against the current....and if you've paralyzed the little rotters, they really can't swim so good...that's my thought.