Localized contacts between hosts reduce pathogen diversity

Area of Science:

• Epidemiology
• Mathematical Biology
• Network Science

Background:

• Pathogen strains can invade populations with existing infections.
• Immunity, both homologous and cross-protective, influences reinfection dynamics.
• Host contact networks impact disease transmission and evolution.

Purpose of the Study:

• To investigate how host contact network structure affects pathogen strain invasion dynamics.
• To understand the role of local versus global contacts in disease spread and pathogen diversity.
• To develop a mean-field model for small-world networks in epidemiological dynamics.

Main Methods:

• Agent-based simulations on small-world networks.
• Modeling pathogen invasion with homologous and cross-immunity.
• Analysis of infection prevalence and strain coexistence under different network structures.

Main Results:

• Increased local contacts in small-world networks significantly reduce infection prevalence compared to well-mixed populations.
• The parameter space for invading strain establishment and coexistence with existing strains is smaller in small-world networks.
• Network structure critically influences the potential for pathogen diversity and evolution.

Conclusions:

• Host contact network topology, particularly the proportion of local interactions, is a key factor in epidemiological outcomes.
• Small-world networks can limit pathogen diversity by restricting the conditions for strain coexistence.
• An effective mean-field model can capture the effects of small-world network structures on epidemiological dynamics.