My father had the same experience. He had UC of 16 years, needed blood transfusions often, profusely bleeding.
He then took an anti parasitic -against the advice of his doctor who said that is not a need in USA. He did so following a friend's suggestion. He stopped bleeding completely.
Later on, he learned that it is best -during the first couple of years or so- to do an antiparasitic treatment every 4-6 months, and then, after that, once a year- to eliminate the eggs, and to not risk bleeding again.