Maintenance of diversity in a hierarchical host-parasite model with balancing selection and reinfection

TL;DR

This paper presents a hierarchical host-parasite model inspired by human cytomegalovirus data, demonstrating how balancing selection and reinfection can sustain parasite diversity over time.

Contribution

It introduces a new model capturing host-parasite dynamics with balancing selection and reinfection, showing long-term diversity maintenance in large populations.

Findings

Host state frequencies follow a stable dynamical system.

Both parasite types are maintained over long periods.

Model aligns with DNA data of cytomegalovirus.

Abstract

Inspired by DNA data of the human cytomegalovirus we propose a model of a two-type parasite population distributed over its hosts. The parasite is capable to persist in its host till the host dies, and to reinfect other hosts. To maintain type diversity within a host, balancing selection is assumed. For a suitable parameter regime we show that in the limit of large host and parasite populations the host state frequencies follow a dynamical system with a globally stable equilibrium, guaranteeing that both types are maintained in the parasite population for a long time on the host time scale.