Fig. 6. Clinical features and viral titres of SARS-CoV-2 in intranasally (IN) or eye-drop (ED)-infected wild-type Syrian hamsters.

Eleven-week-old female Golden Syrian hamsters were IN-mock-infected or infected with 10⁴ PFU of SARS-CoV-2 (n = 6 for mock-infected and n = 5 for infected mice; mock, grey; SARS-CoV-2, red). a Body weight changes are shown as the percentage of the starting weight at the indicated dpi after IN infection. b Syrian hamsters were IN- or ED-infected with 10⁴ PFU of SARS-CoV-2 (each n = 5 for IN-mock-infected, IN-infected, ED-mock-infected, and ED-infected). A graph showing the percent body weight change is shown. c, d Viral loads at 6 dpi in the lungs and eyes of IN-infected (c) and ED-infected (d) hamsters were measured using plaque assay. e, f Viral RNA levels at 6 dpi in the lungs, brain, eye globes, optic nerves (ONs), trigeminal nerves (TNs) and spleens of IN-infected (e) and ED-infected (f) animals were assessed using RT-qPCR. Viral RNA copies were subjected to a cut-off at 10⁴ copies/μg. The dashed line indicates the viral RNA levels of the spleen as a limit of detection. Symbols represent means ± SEMs. Statistically significant differences between the groups were determined using multiple two-tailed t-tests (a, b), unpaired two-tailed t-test (c, d), or one-way ANOVA (e, f). SARS-CoV-2 severe acute respiratory syndrome coronavirus 2, PFU plaque-forming unit, dpi days post-infection.