I personally don't think blasto is the problem, and may just be a co-infection from another protozoa. Once the "intracellular" take hold, it becomes open season in your intestines.
If the basto has been confirmed by a lab, then it could be a a nasty strain you picked up traveling, or contaminated water. These types can be eliminated with bitters, or Antibiotics . If it remains after treatment, I would assume another type is involved.
This is just an opinion! Shroom