Figure 6

Extra-intestinal histopathological changes and distribution of antigen-positive cells in calves infected with bovine G5P[7] RVA strain K5. (A-C) Compared to densely packed lymphocytes (asterisk) in the cortex of normal mesenteric lymph node (MLN) from a mock-inoculated calf (A), MLN from a virus-inoculated calf shows lymphoid cell depletion (asterisk) in the cortex (B) and RVA antigen-positive cells (arrows) (C). (D-F) Lung sampled from a mock-inoculated calf reveals normal thin alveolar wall (arrows) (D), whereas lung sampled from a virus-inoculated calf shows interstitial pneumonia (arrows) (E) and RVA antigen-positive reaction in the pneumocyte (arrowhead) and lymphoid cell (arrow) (F). (G-I) Compared to normal hepatocytes (arrows) from a mock-inoculated calf (G), liver sampled from a virus-inoculated calf shows multiple scattered necrotic hepatocytes (arrows) (H) and RVA antigen-positive cells (arrows) (I). (J-L) Choroid plexus sampled from a mock-inoculated calf has intact epithelium (arrowheads) (J), whereas choroid plexus sampled from a virus-inoculated calf displays epithelial degeneration (arrowhead) and necrosis (arrows), and lymphoid cell infiltration (double arrow) into the tela choroidea (H), and RVA antigen-positive cells (arrow) (L). Hematoxylin and eosin stain (A, B, D, E, G, H, J, and K). Indirect immunofluorescence assay with monoclonal antibody against the VP6 protein of strain OSU (C, F, I, and L). Bars denote 100 μm.