Pulsating fronts for Fisher-KPP systems with mutations as models in evolutionary epidemiology

TL;DR

This paper studies a reaction-diffusion system modeling competing pathogens with mutations in a heterogeneous environment, establishing the existence of pulsating traveling fronts without relying on comparison principles.

Contribution

It introduces the first construction of pulsating fronts in a non-cooperative reaction-diffusion system with mutations, using bifurcation techniques.

Findings

Existence of nontrivial positive steady states established.

Construction of pulsating fronts in a non-cooperative setting.

First such construction without comparison principles.

Abstract

We consider a periodic reaction diffusion system which, because of competition between $u$ and $v$, does not enjoy the comparison principle. It also takes into account mutations, allowing $u$ to switch to $v$ and vice versa. Such a system serves as a model in evolutionary epidemiology where two types of pathogens compete in a heterogeneous environment while mutations can occur, thus allowing coexistence.We first discuss the existence of nontrivial positive steady states, using some bifurcation technics. Then, to sustain the possibility of invasion when nontrivial steady states exist, we construct pulsating fronts. As far as we know, this is the first such construction in a situation where comparison arguments are not available.