Investigation of the First African Swine Fever Outbreak in a Domestic Pig Farm in Hong Kong

Figure 4

Post-mortem examination of index ASFV infected pig. Left panels: gross findings of index pig on day 0. (a) Skin lesions of multiple well-demarcated irregular patches (black arrows) are slightly raised and often with a rim of red to brown discoloration. (b) Pulmonary congestion and diffuse pulmonary edema (red arrows: prominent interlobular septa). (c) Splenomegaly with mildly round edges and congestion (red arrow). (d) Renal lymph node hemorrhages. Right panels: histopathological examination of index pig on day 0. (e) Multifocal to coalescing edema in the alveolar spaces and the interlobular septa (lung, H&E, 40X). (f) Bronchus-associated lymphoid tissue necrosis and fibrinonecrotic alveolitis/vasculitis (lung, H&E, 400X). (g) Lymphoid necrosis (spleen, H&E, 400X). (h) Necrotic focus with hemorrhage (pancreas, H&E, 100X). (i) Necrotic epidermis and suppurative infiltrate with fibrin thrombi in the blood vessels in the superficial dermis (skin, H&E, 100X). (j) Vasculitis and spilling of inflammatory cells to the adjacent cerebral parenchyma (brain, H&E, 400X).