Emergence of synergistic and competitive pathogens in a co-evolutionary spreading mode

TL;DR

This paper models the co-evolution of two pathogens during simultaneous spreading, revealing how their interactions and strategies influence epidemic outcomes and can lead to the dominance of a single pathogen species.

Contribution

It introduces a co-evolutionary model with pathogen strategies based on a hawk-and-dove game, highlighting the impact on epidemic prevalence and pathogen dominance.

Findings

Abrupt transitions in epidemic prevalence due to pathogen strategy evolution

Emergence of cooperative behavior under unfavorable conditions

Long-term dominance of a single pathogen species

Abstract

Cooperation and competition between pathogens can alter the amount of individuals affected by a co-infection. Nonetheless, the evolution of the pathogens' behavior has been overlooked. Here, we consider a co-evolutionary model where the simultaneous spreading is described by a two-pathogen susceptible-infected-recovered model in an either synergistic or competitive manner. At the end of each epidemic season, the pathogens species reproduce according to their fitness that, in turn, depends on the payoff accumulated during the spreading season in a hawk-and-dove game. This co-evolutionary model displays a rich set of features. Specifically, the evolution of the pathogens' strategy induces abrupt transitions in the epidemic prevalence. Furthermore, we observe that the long-term dynamics results in a single, surviving pathogen species, and that the cooperative behavior of pathogens can emerge even under unfavorable conditions.