Persistent spatial patterns of interacting contagions

Area of Science:

• Epidemiology
• Mathematical Biology
• Spatial Dynamics

Background:

• Contagion processes like disease spread are complex, influenced by networks and spatial factors.
• While network-based contagion is well-studied, spatial contagion dynamics, especially with interacting infections, remain underexplored.

Purpose of the Study:

• To investigate spatial pattern formation in interacting contagion processes involving two simultaneous infections (A and B).
• To analyze how interactions affect secondary infection propensity and spatial diffusion patterns.

Main Methods:

• Utilized susceptible-infected-susceptible (SIS) kinetics for individual contagion processes.
• Employed mathematical modeling and linearization analysis to study pattern formation and stability.
• Investigated the role of susceptible mobility and infection interaction strength on spatial patterns.

Main Results:

• Nontrivial spatial infection patterns emerge when susceptible individuals move faster than infected ones, and interactions are moderately competitive or cooperative.
• Observed pattern hysteresis, where distinct parameter regions for patterns exist depending on whether R₀ increases or decreases.
• Found that decreasing R₀ significantly enhances contagion prevalence, complicating eradication efforts compared to non-spatial or single-infection models.

Conclusions:

• Interacting spatial contagions can generate complex patterns, akin to Turing patterns, driven by mobility and interaction dynamics.
• Pattern hysteresis and enhanced prevalence upon decreasing R₀ highlight unique challenges in managing co-circulating infections in space.
• Findings have implications for understanding and controlling the spread of biological and social contagions.