Cryptosporidiosis, coccidiosis, and total colonic mucosal collapse in an immunosuppressed puppy.

An eight-week-old puppy with chronic diarrhea was diagnosed with simultaneous opportunistic pathogens (i.e., cryptosporidiosis, coccidiosis) and total colonic mucosal collapse. Lack of lymphoid follicles in the spleen and lymph nodes suggested a primary underlying immunosuppression that most likely permitted infection with these pathogens. Intensive antibiotic therapy was most likely responsible for the severe colonic lesion, and bismuth subsalicylate administration in this severely dehydrated puppy may have contributed to renal failure as the ultimate cause of death.