Characterization of Pseudorabies Virus Associated with Severe Respiratory and Neuronal Signs in Old Pigs

Figure 5

Histological examinations of different tissues of pigs inoculated with different pseudorabies virus (PRV) strains (bar = 200 μm). Histological damages in the lungs included an infiltration of massive inflammatory cells in alveolar spaces as well as pulmonary interstitial fibrosis and thickening. In the brains, many blood vessels as well as degenerated and necrotic glial nodules and nerve cells were observed particularly those of pigs challenged with HeN21. Lymphocyte necrosis with a large number of red blood cells filled in lymph nodes; the structures of lymph nodes disappeared. Degeneration and necrosis of epithelial cells appeared in tonsils. Notably, challenging of HeN21 and HuB20 resulted in necrosis of liver cells and congestion in the central vein in the livers.