Transmission-recovery trade-offs to study parasite evolution.
Parasite evolution is mainly studied through a trade-off involving host death (i.e., virulence) and transmission. In addition to the lack of evidence, this trade-off largely fails to understand the evolution of sublethal parasite effects. Here, I argue that considering host recovery as a main selection pressure faced by the parasite helps to address these problems and opens new perspectives for the study of parasite evolution. Using an embedded model, I show how a trade-off between transmission and recovery may emerge from within-host dynamics if immune activation is assumed to depend on the parasite's overall growth rate. I also show that the value of the parasite's optimal growth rate strongly depends on the immunological state of the host. Transmission-recovery trade-offs are of particular interest to the study of the evolution of human pathogens because of the use of antipathogen treatments, which strengthens the recovery constraint.
Alizon
Samuel
S
Department of Mathematics and Statistics, Queen's University, Kingston, Ontario K7L 3N6, Canada. samuel@mast.queensu.ca
D005075:Biological Evolution; D018562:Disease Transmission, Infectious; D006790:Host-Parasite Interactions; D008954:Models, Biological; D020127:Recovery of Function; D012641:Selection, Genetic