Invasion threshold in heterogeneous metapopulation networks

TL;DR

This paper analyzes how the structure of heterogeneous metapopulation networks influences epidemic spread, identifying a critical invasion threshold affected by network topology and mobility rates, informing containment strategies.

Contribution

It provides an explicit expression for the invasion threshold in heterogeneous networks, linking network topology and mobility to epidemic spread control.

Findings

Existence of a global invasion threshold in heterogeneous networks

Threshold depends on network topology and diffusion rate

Travel restrictions can effectively prevent epidemic spread

Abstract

We study the dynamics of epidemic and reaction-diffusion processes in metapopulation models with heterogeneous connectivity pattern. In SIR-like processes, along with the standard local epidemic threshold, the system exhibits a global invasion threshold. We provide an explicit expression of the threshold that sets a critical value of the diffusion/mobility rate below which the epidemic is not able to spread to a macroscopic fraction of subpopulations. The invasion threshold is found to be affected by the topological fluctuations of the metapopulation network. The presented results provide a general framework for the understanding of the effect of travel restrictions in epidemic containment.