Natural infection with attaching and effacing Escherichia coli and adenovirus in the intestine of a pigeon with diarrhea.

Attaching and effacing Escherichia coli (AEEC) and adenovirus infections in a 6-month old pigeon were found by retrospective histologic examinations. Histologically, numerous gram-negative bacilli covered the surface of the enterocytes of the ileum. Brush borders were not sharply defined on the apical enterocytes at the sites of bacterial attachment. Scanning electron microscope showed that much of the mucosal surface was heavily colonized by bacilli and that the microvilli were lost. Many intranuclear inclusions were seen in enterocytes from the duodenum to the cecum. On transmission electron microscopy, adenovirus-like particles were observed in the nuclei of enterocytes.