Cryptosporidiosis leading to an unsuspected diagnosis of AIDS.

We describe a 68-year-old woman with an episode of diarrhoea, malaise and weight loss, caused by infection with Cryptosporidium. The diagnosis was hampered because this patient had a low risk of HIV infection, a two-year history of Crohn's disease, and a simultaneous candidal infection. An infection with Cryptosporidium was demonstrated with electron microscopic examination, and subsequent tests revealed positive HIV serology.