Fig. 1

Histologic and ultrastructural findings in a calf with systemic adenoviral infection. A, B Necrotic foci (asterisks) within the liver A and spleen B, with numerous intralesional, amphophilic, intranuclear inclusions (arrows). C Lymph node with intravascular, fibrinocellular thrombi (asterisk), perifocal edema and associated intranuclear viral inclusions. All examined lymphoid tissues also showed generalized depletion. D Rete mirabile showing intrendothelial viral inclusions (arrows) and associated fibrin accumulation (arrowhead). E, F Viral inclusions not associated with overt histopathological lesions were detected in many other tissues, including kidney E and bone marrow F. G Electron microscopy of liver tissue showing nucleus with marginalized, condensed chromatin and intranuclear viral particles measuring ~ 70 nm in diameter and partly arranged in a crystalline array. H Similar viral particles are present within a necrotic cell in the spleen. A–F, H & E staining, scale bars: 20 µm. G, H, transmission electron microscopy, scale bars: 500 nm and 100 nm (insert)