Human mobility networks and persistence of rapidly mutating pathogens

TL;DR

This study investigates how human mobility networks influence the persistence and spread of rapidly mutating pathogens using a metapopulation model, revealing that intermediate mobility levels maximize disease persistence.

Contribution

It introduces a comprehensive numerical analysis of pathogen dynamics on mobility networks, highlighting the critical role of spatial fragmentation and mobility in disease persistence.

Findings

Maximum pathogen persistence occurs at intermediate mobility levels.

Spatial fragmentation influences local extinction and epidemic wave emergence.

Mobility patterns affect large-scale disease spread.

Abstract

Rapidly mutating pathogens may be able to persist in the population and reach an endemic equilibrium by escaping hosts' acquired immunity. For such diseases, multiple biological, environmental and population-level mechanisms determine the dynamics of the outbreak, including pathogen's epidemiological traits (e.g. transmissibility, infectious period and duration of immunity), seasonality, interaction with other circulating strains and hosts' mixing and spatial fragmentation. Here, we study a susceptible-infected-recovered-susceptible model on a metapopulation where individuals are distributed in subpopulations connected via a network of mobility flows. Through extensive numerical simulations, we explore the phase space of pathogen's persistence and map the dynamical regimes of the pathogen following emergence. Our results show that spatial fragmentation and mobility play a key role in the persistence of the disease whose maximum is reached at intermediate mobility values. We describe the occurrence of different phenomena including local extinction and emergence of epidemic waves, and assess the conditions for large scale spreading. Findings are highlighted in reference to previous works and to real scenarios. Our work uncovers the crucial role of hosts' mobility on the ecological dynamics of rapidly mutating pathogens, opening the path for further studies on disease ecology in the presence of a complex and heterogeneous environment.