* Histopathology can establish a positive diagnosis from endoscopic biopsy or surgical biopsy. Negative histology does not rule out cryptosporidiosis because of the non-uniform distribution of ''Cryptosporidia''. | * Histopathology can establish a positive diagnosis from endoscopic biopsy or surgical biopsy. Negative histology does not rule out cryptosporidiosis because of the non-uniform distribution of ''Cryptosporidia''. |