Dynamical behaviour of SIR model with coinfection: the case of finite carrying capacity

TL;DR

This paper models the coinfection dynamics of two viruses in a population with limited growth, showing that increased carrying capacity can promote infection risk and lead to population destabilization.

Contribution

It introduces a novel SIR model incorporating coinfection and finite carrying capacity, analyzing stability and disease persistence.

Findings

Disease persists for all parameters due to a globally stable equilibrium.

Higher carrying capacity increases infection risk and can destabilize the population.

The model links resource availability directly to infection dynamics.

Abstract

Multiple viruses are widely studied because of their negative effect on the health of host as well as on whole population. The dynamics of coinfection is important in this case. We formulated a SIR model that describes the coinfection of the two viral strains in a single host population with an addition of limited growth of susceptible in terms of carrying capacity. The model describes four classes of a population: susceptible, infected by first virus, infected by second virus, infected by both viruses and completely immune class. We proved that for any set of parameter values there exist a globally stable equilibrium point. This guarantees that the disease always persists in the population with a deeper connection between the intensity of infection and carrying capacity of population. Increase in resources in terms of carrying capacity promotes the risk of infection which may lead to destabilization of the population.