A comparison of the five herpesviral networks revealed that the degree distribution differed from cellular networks, local clustering was not as high as expected in small-world networks of this size (Figures 1C and S5 and Table S4 ), and attack tolerance and robustness were increased compared to cellular networks ( Figure 1D and S6), probably reflecting that the viral interactome in itself only represents a minor part of the complete interactome of the infected cell. In a previous study we observed that the topology of the KSHV and VZV networks approached that of cellular networks as the viral interactomes were connected into a human interactome [23] . The observations presented here confirm our previous findings, and indicate that herpesviral PPI networks share an evolutionarily conserved topology.