Locally self-organized quasicritical percolation in a multiple-disease model

Area of Science:

• Epidemiology
• Complex Systems Science
• Theoretical Ecology

Background:

• Pathogens and hosts engage in a dynamic evolutionary battle, with diseases emerging and vanishing based on host availability.
• Host immunity is a key defense mechanism, limiting pathogen reinfection and influencing disease persistence.
• Understanding multi-disease systems is crucial for predicting disease dynamics and public health outcomes.

Purpose of the Study:

• To investigate the self-organization dynamics of a multi-disease system with mutual exclusion.
• To determine if such systems approach a steady state and characterize its properties.
• To analyze the relationship between new disease introduction rates and disease transmission likelihood.

Main Methods:

• Modeling a multi-disease system incorporating host immunity and pathogen competition.
• Analyzing the system's evolution towards a steady state.
• Investigating the concept of critical percolation in disease spread dynamics.
• Simulating the impact of varying disease introduction rates.

Main Results:

• The multi-disease system self-organizes to a steady state near critical percolation.
• This critical state is achieved without global control or timescale separation.
• Disease transmission likelihood remains remarkably constant across a wide range of new disease introduction rates.

Conclusions:

• Complex disease systems exhibit emergent self-organization towards a critical state.
• Host-pathogen interactions can lead to stable transmission dynamics independent of new disease influx.
• The findings offer insights into the fundamental principles governing infectious disease persistence and evolution.