(A and B) Ileum from a rabbit with severe diarrhea. The lumen contains large amounts of fibrinonecrotic debris (asterisk), numerous heterophils, and pyknotic nuclei. The sections were stained with H&E. Bars, 500 μm (A) and 25 μm (B). (C and D) Duodenum from a rabbit with severe diarrhea. A fibrin tag is adherent to the serosal surface (arrow) and a fibrinonecrotic cap containing heterophils is adherent to the luminal mucosa (asterisk). H&E stain. Bars, 100 μm (C) and 50 μm (D). (E) Cecum from a rabbit with severe diarrhea. Clusters of heterophils and pyknotic nuclei are present at crypt tips. H&E stain. Bar, 25 μm. (F) Adherence of EPEC O145:H2 (REP-PCR genotype 1) isolates to HEp-2 cells. These isolates displayed a localized adherence-like (LAL) pattern (arrow). Magnification, ×1,000.