Table 1

The gross findings in the pig infected by ASFV"

Fig. 1

The gross changes in the pig A. Multifocal ecchymoses on the dermis of the neck (red arrow); B. Incision of skin ecchymosis in Figure A showed hemorrhage in the subcutaneous tissue (red arrow); C. The lymph node is swollen and hemorrhagic, with blood flowing out of its cut surface (yellow arrow); D. Severe hemorrhage in the gastric hilar lymph nodes (yellow arrow), pancreas (red arrow), and the mesenteric area adjacent to the colon (red arrow); E. The mesenteric lymph nodes are enlarged and hemorrhagic(yellow arrow), with multifocal hemorrhagic foci in the mesentery(red arrow); F. The spleen exhibits enlargement, with a dark-red congestion appearance and a soft texture"

Fig. 2

The gross changes of the ASFV infected pig A. Severe diffuse hemorrhage on the serous surface of the bladder, with dark-red appearance (star); When the bladder was cut longitudinally, there was severe hemorrhage on the mucosa; B. Upon longitudinal incision of the bladder, severe hemorrhage is visible on the mucosal surface (yellow arrow); C. Cross-sections of both kidneys showing congestion and hemorrhage in the renal pelvis (yellow arrow); D. Patchy hemorrhage on the epicardium of the heart (yellow arrow); E. The entire lung is congested and edematous, with patchy hemorrhages in both cardiac lobes (yellow arrow); F. Scattered hemorrhagic foci on the dura mater of the brain (red arrow), with obvious congestion of the pia mater"

Fig. 3

The histopathological changes in the lymph node, heart and kidney tissues of the ASFV infected pig (HE staining) A. At low magnification, diffuse hemorrhage is visible in the medullary region of the lymph node, filled with numerous red blood cells (red arrow); B. Local magnification of the hemorrhagic area in Figure A (red arrow); C. Diffuse hemorrhage in the endocardium and myocardial layer (red arrow); D. At high magnification, numerous red blood cells are present between the myocardial fibers (red arrow); E. Patchy hemorrhage in the renal pelvis of the kidney (red arrow); F. The submucosal and muscular layers of the bladder are filled with numerous red blood cells (asterisk)"

Fig. 4

The histopathological changes in the spleen, lung and liver tissues of the ASFV infected pig (HE staining) A. The splenic parenchyma is almost replaced by red blood cells (red arrow); B. The white pulp area of the spleen is filled with red blood cells, admixed with a small number of lymphocytes (red arrow); C. In the lungs, the small arteries and alveolar capillary walls are congested (red arrow); D. Under high magnification of the lungs, microthrombi are visible in the alveolar capillary walls (yellow arrow), and there is a large amount of pinkish exudate and hemorrhage in the alveolar cavities (red arrow); E. The central area of the hepatic lobules in the liver shows congestion and hemorrhage(red arrow); F. The portal areas of the liver have a large number of neutrophils (red arrow) and lymphocytic infiltration (yellow arrow)"

Fig. 5

Distribution of ASFV antigen in the tissues of the ASFV infected pig (Immunohistochemical staining) A. Lymph node, with strongly positive ASFV antigen reaction in the cytoplasm of macrophages within lymph follicles (indicated by the red arrow); B. Spleen, showing strongly positive ASFV antigen in the cytoplasm of macrophages in the red pulp area (indicated by the red arrow); C. Lung, with strongly positive ASFV in the cytoplasm of alveolar macrophages (indicated by the red arrow); D. Kidney, with scattered positive ASFV antigen in the cytoplasm of renal tubular epithelial cells (indicated by the red arrow)"