Histopathological lesions in the gizzard. Gizzard from a commercial broiler experimentally infected on the first day-of-life with virulent FAdV-1. a) Expansion of the lamina propria mucosa by mixed population of inflammatory cells (arrowheads). Basophilic intranuclear inclusion bodies in degenerated epithelial cells (arrows). Haematoxilin & eosin staining. Bar = 20 μm. b) In-situ hybridization of the same gizzard sample with positive signal for FAdV-1 DNA in epithelial cells (arrows). Bar = 20 μm.