Fig. 4

D614G infection but not Delta or Omicron BA.1 infection increases the number of Iba-1⁺ microglia/macrophages in the olfactory bulb. A Hematoxylin and eosin (H&E) staining of the glomerular layer in the olfactory bulb. Detection of Iba1⁺ cells and CD3⁺ cells in the glomerular layer of the olfactory bulb. Counting of B Iba-1⁺ cells and C CD3.⁺ cells in the glomerular layer and the granular cell layer of the olfactory bulb. Statistical significance was calculated with a One-Way analysis of variance (ANOVA) with a Dunnett’s posthoc test. Averaged values of four individual animals per infection group were compared to values of four mock treated animals. Asterisks indicate statistical significance*, P < 0.05)