Figure 4: Rhesus macaque model – gross and histopathology.

Macaques were infected with SARS-CoV-2 as described in the legend of Figure 2. Animals were euthanized on day 7 post-infection for gross pathology and histopathology. (A and B) Gross pathology with consolidated lower left lung lobe and area of post-mortem-BAL in the lower right lung lobe (asterisk). (C) Hematoxylin and eosin (H&E) staining revealed multifocal, minimal to moderate, interstitial pneumonia frequently centered on terminal bronchioles. Alveolar edema and fibrin with formation of hyaline membranes was only seen in lungs with moderate changes. Multifocal perivascular infiltrates of small numbers of lymphocytes that form perivascular cuffs. The left panels show areas of unaffected lung tissue. Note: PS, prophylaxis; TS, treatment.