SARS-CoV-2 detection in lung tissue by transmission electron microscopy. A, SARS-CoV-2 particles are visible in virus-containing compartments in type II pneumocytes (arrows). B–D, Numerous viral particles are enclosed in single-membrane vacuoles (arrow). Other, very small vesicles contain single viral particles (arrowheads). Scale bars: A, 1 µm; B–D, 200nm.