Mutually cooperative epidemics on power-law networks

Area of Science:

• Epidemiology
• Network Science
• Mathematical Biology

Background:

• Infectious disease spread can be influenced by coinfecting pathogens.
• Cooperative dynamics between pathogens can lead to complex outbreak patterns.
• Network topology significantly impacts disease propagation and endemic states.

Purpose of the Study:

• To investigate coinfection dynamics of two mutually cooperative pathogens.
• To analyze the role of network heterogeneity and cooperativity on epidemic transitions.
• To explore the transition nature in uncorrelated power-law degree-distributed networks.

Main Methods:

• Development of a heterogeneous mean-field theoretical approach.
• Modeling susceptible-infected-removed (SIR) dynamics for two cooperative pathogens.
• Validation through numerical simulations on various network topologies.

Main Results:

• For finite second moments of degree distribution, transitions are continuous at low cooperativity and discontinuous at high cooperativity.
• For scale-free networks (diverging second moment), transitions are always continuous.
• Clarified the influence of heterogeneity and system size on transition discontinuity.

Conclusions:

• Network heterogeneity and pathogen cooperativity critically influence epidemic transition types.
• Scale-free networks exhibit continuous transitions regardless of cooperativity.
• The study provides insights into the mechanisms driving discontinuous epidemic transitions.