Animals 1 Biological Evolution 1 Host-Parasite Interactions 1 Models, Biological 1 Parasites 1 Virulence 1 age distribution 1 age structure 1 age-structure 1 animal 1 article 1 biological model 1 evolution 1 evolutionary theory 1 force of infection genetics 1 host parasite interaction 1 mortality 1 mortality rate 1 parasite 1 parasite virulence 1 prediction 1 senescence 1 virulence 1 vrulence 1