Small intestine: Cryptosporidium parvum with HIV

Cryptosporidiosis: Cryptosporidium parvum (a diarrhoea causing parasite) in the small intestine. This is a high power view through a crypt of Lieberkühn in the duodenum. Cryptosporidia are present in the mucosa. The organisms appear to lie on the surface of the mucosa, but they are in fact intracellular. The patient was HIV-seropositive. H&E stain.