Figure 4.

Morphologic changes and viral localization in the heart of the SARS-CoV-2 infected cat. (A) Myocardial degeneration and necrosis. Cardiomyocytes with hypereosinophilic sarcoplasm with hypercontraction bands and loss of striations. Small numbers of neutrophils and macrophages in the myocardial interstitium. Hematoxylin and eosin. 40× magnification. (B) Electron microscopy of the ventricular myocardium. A blood vessel containing portions of two erythrocytes (lower left) and lined by two endothelial cells, each with a partial profile of the nucleus. Multiple coronavirus-like particles are within endoplasmic reticulum cisternae or are adjacent to free ribosomes and fragmented cytosolic debris (autolysis) (panel a). Bar = 2 µm. Panel b—Higher magnification of panel a. Virus particles are round with an outer double membrane and a core that contains variably distinct electron dense dots representing cross sections of the nucleocapsid. Bar = 1 µm.