My idea of prebiotics may be different - colostrum I suppose couild be classified http://www.secrets-of-longevity-in-humans.com/colostrum-benefits.html
and fiber serves as a vehicle for the probiotics. But in the original poster's case the primary problem is the parasitic infection which supercedes everything else.
These infections alter bowel ecology quite dramactically and shift immune response - they are the top-feeders in the gut.