Figure 4

Extra-intestinal histopathological changes and distribution of antigen-positive cells in piglets infected with porcine G5P[7] RVA strain K71. (A-C) Compared to densely packed lymphocytes (asterisk) in the cortex of normal mesenteric lymph node (MLN) from a mock-inoculated piglet (A), MLN from a virus-inoculated piglet showed lymphoid cell depletion (asterisk) in the cortex (B) and RVA antigen-positive cells (arrows) (C). (D-F) The lung sampled from a mock-inoculated piglet revealed normal thin alveolar wall (arrows) (D), whereas the lung sampled from a virus-inoculated piglet showed interstitial pneumonia (arrows) (E) and RVA antigen-positive cells (arrow) (F). (G-I) Compared to normal fat-storing hepatocytes (arrows) from a mock-inoculated piglet (G), liver sampled from a virus-inoculated piglet showed multiple scattered necrotic hepatocytes (arrows) (H) and RVA antigen-positive cells (arrows) (I). (J-L) Choroid plexus sampled from a mock-inoculated piglet had an intact epithelium (arrowheads) (J), whereas choroid plexus sampled from a virus-inoculated piglet displayed epithelial degeneration (arrowheads) and necrosis (arrows), and lymphoid cell infiltration (double arrow) into the tela choroidea (H), and RVA antigen-positive cells (arrows) (L). Hematoxylin and eosin stain (A, B, D, E, G, H, J, and K). Indirect immunofluorescence assay with monoclonal against the VP6 protein of strain OSU (C, F, I and L). Bars denote 100 μm.