Epidemics and immunization in scale-free networks
  In this chapter we want to provide a review of the main results obtained in the modeling of epidemic spreading in scale-free networks. In particular, we want to show the different epidemiological framework originated by the lack of any epidemic threshold and how this feature is rooted in the extreme heterogeneity of the scale-free networks' connectivity pattern. 
Romualdo Pastor-Satorras and Alessandro Vespignani