Effect of resistant compartment on pathogen strategy in partially migratory populations

Migration, the recurring movement of animals between habitats, can exert pressures on the pathogens they host. Properties of host populations can determine pathogen strategy (e.g. virulence) to increase pathogen fitness. To study the effect of adding a resistant compartment on virulence evolution, we developed an SIRS model and examined the winning pathogen strategy across different rates of recovery and of immunity loss. We find that when hosts spend a relatively long time in the resistant class, a more virulent pathogen evolves. These results have implications in conservation of migratory animal populations afflicted by disease.