Quantitatively, RPV-Sa and PPRV-Tu showed a 95% block (Fig. 1b); the small percentage (5%) of RPV-Sa and PPRV-Tu infected cells in which phosphorylated STAT1 could be seen in the nucleus appeared to be in early stages of infection, as judged by lower levels of viral proteins in such cells, and this could have resulted in their inability to completely block the IFNα signal. Here, STAT1 is linked to infection.