Critical behavior of an epidemic model of drug resistant diseases

TL;DR

This paper investigates the critical behavior of a lattice epidemic model that includes drug resistance, analyzing phase transitions and their universality class through finite-size scaling.

Contribution

It introduces a lattice epidemic model with drug resistance and characterizes its phase transitions, identifying their universality class as directed percolation.

Findings

Identified two active phases: co-existing normal and resistant infections, and resistant-only infections.

Computed critical points and exponents using finite-size scaling.

Found that phase transitions belong to the directed percolation universality class.

Abstract

In this work, we study the critical behavior of an epidemic propagation model that considers individuals that can develop drug resistance. In our lattice model, each site can be found in one of four states: empty, healthy, normally infected (not drug resistant) and strain infected (drug resistant) states. The most relevant parameters in our model are related to the mortality, cure and mutation rates. This model presents two distinct stationary active phases: a phase with co-existing normal and drug resistant infected individuals and an intermediate active phase with only drug resistant individuals. We employ a finite-size scaling analysis to compute the critical points the critical exponents ratio $\beta/\nu$ governing the phase-transitions between these active states and the absorbing inactive state. Our results are consistent with the hypothesis that these transitions belong to the directed percolation universality class.