Fig. 4: Systemic spread of MPXV clade IIa and clade IIb after intradermal infection 12 days post infection.
CAST/EiJ were infected with 2 × 104 PFU or 2 × 105 PFU of MPXV clade IIa (2 x 104: n = 8; 2 × 105: n = 8) or IIb (2 × 104: n = 8; 2 × 105: n = 7) using tail skin scarification. PBS served as a control (n = 2 each). Mpox-specific target organs (lung, spleen, liver) were prepared at the day of death and assayed for (a, b) infectious virus titres and (c, d) viral DNA after 2 × 104 PFU and 2 × 105 PFU infection. In addition, oropharyngeal swabs (o-swab) and skin swabs (s-swab) were taken on day 4 post infection and on the day of death (final) and analysed for (e, f) the viral load (PFU/ml) and (g, h) the amount of viral DNA. Dot shapes (shaded blue as required) represent mice that were sacrificed at the end of the experiment on day 12 and rhombus shapes illustrate mice that were euthanized prematurely due to humane endpoint assessment. Titration and qPCR were performed once with two technical replicates. Error bars show the geometric mean ± geometric standard deviation (SD). P values were determined by Kruskal-Wallis test with Dunn´s multiple comparisons test (a-d, f-h) and two-tailed Mann-Whitney test (e). *p = 0.0295 PBS versus IIa (spleen), *p = 0.0482 PBS versus IIa (liver) in b. **p = 0.0078 IIa versus IIb (spleen), *p = 0.023 IIa versus IIb (liver) in c. *p = 0.0302 PBS versus IIa (lung), *p = 0.0202 PBS versus IIa (spleen), *p = 0.0158 IIa versus IIb (spleen) in d. *p = 0.0275 IIa versus IIb (o-swab final), *p = 0.0444 PBS versus IIa (s-swab final) in e. *p = 0.0458 PBS versus IIa (o-swab final), *p = 0.0234 IIa versus IIb (o-swab final), *p = 0.0319 PBS versus IIa (s-swab final) in f. *p = 0.0448 PBS versus IIa (s-swab final) in g. *p = 0.0225 PBS versus IIa (o-swab final), *p = 0.0167 IIa versus IIb (o-swab final), *p = 0.0142 PBS versus IIa (s-swab final), *p = 0.0192 IIa versus IIb (s-swab final) in h. Dotted line: detection limit. Source data are provided as a Source Data file.
