Fig. 1. Clinical features and virus titres in the eyes of SARS-CoV-2-infected mice.

Eight- to nine-week-old male K18-hACE2 mice were intranasally mock-infected or infected with 10⁴ PFU of SARS-CoV-2 (n = 5 for mock- and SARS-CoV-2-infected mice, respectively; Mock, Grey; SARS-CoV-2, Red). a Body weight changes shown as percentage of starting weight. b Survival was evaluated at the indicated dpi. c Representative image of tearing and eye discharge in SARS-CoV-2-infected mice at 6 dpi (right) compared to those in mock-infected mice (left). d Viral load in the lungs and eyes, including appendages, was analysed using a plaque assay at 6 dpi. e Viral RNA levels in the lungs, brain, eyes, including appendages, lacrimal gland, parotid gland and spleen were assessed using RT-qPCR at 6 dpi. Viral RNA copies were cut-off (10⁴ copies/μg). A dashed line indicates the viral RNA levels of the spleen as a limit of detection. f Representative confocal images of immunofluorescence stained retinal sections of IN-infected mice (n = 3 per group) for viral spike (S) protein (red) at 6 dpi. DAPI staining (blue) was used to visualise nuclei of the ganglion cell layer (GCL), inner nuclear layer (INL), and outer-nuclear layer (ONL) in the retinal cross-section. Scale bar = 100 μm. Symbols represent means ± SEM. Statistically significant differences between the groups were determined using multiple two-tailed t-tests (a), unpaired two-tailed t-test (d) or one-way ANOVA (e). SARS-CoV-2: severe acute respiratory syndrome coronavirus 2; PFU plaque-forming unit, vRNA viral RNA, dpi days post-infection.