Fig. 1. Hyperemia of capillaries of pulmonary alveoli and mononuclear infiltration were shown. Fibrin and red blood cells could be found inside the alveolar spaces. (HE staining, original magnification×200).
Fig. 2. Thickened basement membranes of capillaries and widened walls of pulmonary alveoli with fibrinous deposition were detected. (HE staining, original magnification×200).
Fig. 3. Hyaline-membrane formation was observed. (HE staining, original magnification×200).
Fig. 4. Epithelium desquamation of bronchioles mucosa could be detected, together with neutrophils and some fibrous thrombosis in the accompanied vessels. (HE staining, original magnification×200).