Epidemic spreading with time delay in complex networks
  We present a modified \emph{susceptible-infected-susceptible} (SIS) model on complex networks, small-world and scale-free, to study epidemic spreading with the effect of time delay which is introduced to the infected phase. Considering the topology of the network, both uniform and degree-dependent delays are studied during the contagion process. We find that the existence of time delay will enhance both outbreaks and prevalence of infectious diseases in the network. 
Xin-Jian Xu, Hai-Ou Peng, Xiao-Mei Wang, and Ying-Hai Wang