Persons with proven or highly suspected parasitic infections involving the gastrointestinal tract (including amebiasis, giardiasis, hookworm, strongyloidiasis, trichuriasis, pinworm, tapeworm, cyclorsporiasis, cryptosporidia infections, microsporidia infections, isosporidium infections, trichinosis, gastrointestinal dwelling trematodes, coccdioiosis, and echinococccus and additional infections).