Figure 2.

Macroscopic and microscopic examination of organs from the mock- and CSFV-infected pigs. The experimental pigs were sacrificed at 7 dpi and the indicated organs were collected for pathological analyses. Macroscopic examination was performed immediately after sacrifice of the experimental pigs; bar: 10 mm. For microscopic examination, tissue samples were subjected to preparation of tissue sections and Hematoxylin and Eosin (HE) staining, and then histopathological changes were analyzed with a NIKON Eclipse Ci biological microscope (Japan) under a magnification of 200×. Bar: 100 μm. In each panel, the upper left and upper left respectively show gross and microscopic lesions from mock-infected pigs, in which no pathological changes were observed; the lower left and lower right respectively show gross and microscopic lesions from pigs infected with CSFV, and varying degrees of hemorrhagic necrotizing inflammation could be seen in several organs. Histopathological changes as indicated by black arrows with different lengths can be seen in the panels. (A) Spleen, (B) inguinal lymph node, (D) thymus: short arrows indicate hemorrhage, and long arrows show lymphocyte necrosis and disintegration, accompanied with infiltration of inflammatory cells. (C) Tonsil: short arrows indicate flaky necrosis of lymphocytes, and long arrows show inflammatory cell infiltration around the necrotic foci. (E) Kidney: short arrows indicate severe hemorrhage in the superficial cortex, and long arrows show a large amount of inflammatory cell infiltration in the mesenchyma. Alveolar atrophy and alveolar wall thickening (short arrow) as well as inflammatory cell infiltration (long arrow) can be seen in infected lung (F). Hepatocyte steatosis (short arrow) and interstitial cell hyperplasia with concomitant inflammatory cell infiltration (long arrow) in the portal area were observed in infected liver (G). No obvious histopathological changes were obtained in infected heart, except for slight swelling of cardiomyocytes (H). Occasionally, vascular sleeve-like changes can be seen in cerebral parenchyma (I).