Spread of infectious diseases in directed and modular metapopulation networks

We consider epidemics in metapopulations on different network topologies. Recent work on epidemics on networks has focussed on epidemics of humans. In this work, we present a model for epidemics on directed networks, which are found for example in livestock trade. We show that the direction of edges and the modular structure of networks have an impact on the outbreak size and the time of the outbreak peak. In some circumstances, the outbreak size in directed networks can even be larger than in undirected systems. The results presented here could be useful for decision making processes in directed modular systems.