Fig. 5: Systemic spread of MPXV clade IIa and clade IIb after intradermal infection 8 days post infection.

CAST/EiJ mice were infected with 2x10⁵ PFU of MPXV clade IIa (n = 4) or IIb (n = 4) for 8 days using tail skin scarification. PBS served as a control (n = 2). Daily monitoring of (a) body weight and (b) survival was conducted, and (c) general conditions, or (d) the progression of skin lesions was assessed using clinical scores. Mpox-specific target organs (lung, spleen, liver) were harvested at the end of the experiment and assayed for (e) infectious virus and (f) viral DNA. Oropharyngeal swabs (o-swab) from 4 and 8 dpi (final) as well as skin swab samples (s-swab) from day 8 (final) were checked for (g) the amount of infectious virus (PFU/ml) and (h) orthopox DNA. Titration and qPCR were performed once with two technical replicates. Error bars show the median ± 95% confidence interval (CI) (a, c, d) or the geometric mean ± geometric standard deviation (SD) (e-h). The area under the curve (AUC) was calculated for the continuous clinical data (a–d) and grouped AUCs were further used to analyse significant differences between groups over the entire infection period. P values were determined by Kruskal-Wallis test with Dunn’s multiple comparisons test. *p = 0.0191 PBS versus IIa in c. *p = 0.0185 PBS versus IIa and PBS versus IIb in d. *p = 0.0336 PBS versus IIa (spleen), *p = 0.0475 PBS versus IIa (liver) in f. *p = 0.0363 PBS versus IIa (o-swab final), *p = 0.0379 PBS versus IIa (s-swab final) in g. *p = 0.0222 PBS versus IIa (o-swab final) in h. Dotted line: detection limit. ns = not significant. Source data are provided as a Source Data file.