Epidemic spreading in communities with mobile agents

We propose a model of mobile agents to study the epidemic spreading in communities with different densities of agents, which aims to simulate the realistic situation of multiple cities. The model addresses the epidemic process from a community with threshold λ_{c 1} less than the infection rate λ to a community with threshold λ_{c 2} larger than λ through both direct and indirect contacts. By both theoretic analysis and numerical simulations we show that it is possible to sustain the epidemic spreading in the community with λ_{c 2} through contact with another community, provided that the latter is connected with an infected community. This result suggests that for effectively controlling the epidemic spread, we should also pay attention to the risk caused by the infection through indirect contact.