Fig. 6: Evaluating the persistence of SARS-CoV-2 RNA in tissues of AGMs up to 18 weeks post infection.

a–c Representative images of RNAscope RED using the SARS-Spike (S) probe in duodenum, liver, and pancreas in non-infected animals (n = 2), (d–f) 4 weeks post infection (p.i., n = 4), and (g–i) necropsy/18 weeks p.i. (n = 15). RNAscope RED was used to visualize the SARS-S expression frequency in the tissues, counterstained with hematoxylin. Black arrows note the presence of SARS-S copies as red dots by colorimetric RNAscope. j–k Representative validation images of RNAscope RED using the SARS-S probe in lungs of non-infected, and 4 weeks p.i. animals. Tissues were counterstained with hematoxylin. l, m Fluorescent immunohistochemistry in a representative SARS-CoV-2 positive control from 5 technical replicates (l) and a representative stain from 14 animals 18 weeks p.i. (m). Blue = DAPI; Green = anti-SARS antibody. Staining was performed once in each tissue in tandem with controls of the same tissue. n denotes number of independent animals per group.