Extended Data Fig. 2: SARS-CoV-2 infection in extra-pulmonary organs.

a. SARS-CoV-2 RNA in situ hybridization of brain sections from K18-hACE2 mice following intranasal infection with 2.5 x 10⁴ PFU of SARS-CoV-2 at 7 dpi. Images show low-power magnification (scale bars, 100 μm) with a high-power inset. One of six infected mice stained positively for viral RNA in the brain. Images are from this mouse and another that showed virtually no infection in the brain. b–e. Hematoxylin and eosin staining of the brain (b), heart (c), liver (d), kidney (e), and spleen (f) from K18-hACE2 mice following SARS CoV-2 infection at 7 dpi. Scale bars indicate 200 μm. For b, hematoxylin and eosin-stained images correspond to the mouse with high levels of viral RNA by ISH and show inflamed vessels with extravasation of immune cells into the brain parenchyma, microglial activation, and subarachnoid inflammation with involvement of the underlying parenchyma. The dashed box in b indicates the location of two higher power magnification images below. For a–f, Representative images from 2 independent experiments, n = 6 per group.