In post-mortem, the lungs show consolidation in different degrees. Serum, fibrinous exudate, and transparent membrane formation are seen in the alveolar cavity; exudation cells are mainly monocytes and macrophages, and multinucleated giant cells are easily seen. Type 2 alveolar epithelial cells are proliferated significantly, and some of the cells shed. Inclusion bodies can be seen in type 2 alveolar epithelial cells and macrophages. Alveolar septal vascular congestion and edema, monocyte and lymphocyte infiltration, and intravascular thrombosis can be seen.