title: Evolutionary suicide through a non-catastrophic bifurcation: adaptive dynamics of pathogens with frequency-dependent transmission.
abstract: Evolutionary suicide is a riveting phenomenon in which adaptive evolution drives a viable population to extinction. Gyllenberg and Parvinen (Bull Math Biol 63(5):981-993, 2001) showed that, in a wide class of deterministic population models, a discontinuous transition to extinction is a necessary condition for evolutionary suicide. An implicit assumption of their proof is that the invasion fitness of a rare strategy is well-defined also in the extinction state of the population. Epidemic models with frequency-dependent incidence, which are often used to model the spread of sexually transmitted infections or the dynamics of infectious diseases within herds, violate this assumption. In these models, evolutionary suicide can occur through a non-catastrophic bifurcation whereby pathogen adaptation leads to a continuous decline of host (and consequently pathogen) population size to zero. Evolutionary suicide of pathogens with frequency-dependent transmission can occur in two ways, with pathogen strains evolving either higher or lower virulence.
authors.affiliation: Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Glagoljaška 8, 6000, Koper, Slovenia. barbara.boldin@upr.si.
authors.forename: Barbara
authors.initials: B
authors.lastname: Boldin
authors.affiliation: Department of Mathematics and Statistics, University of Helsinki, P.O. Box 68, 00014, Helsinki, Finland.
authors.forename: Éva
authors.initials: É
authors.lastname: Kisdi
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D005075:Biological Evolution; D003141:Communicable Diseases / Q000635:transmission*; D053476:Extinction, Biological; D005260:Female; D054884:Host-Pathogen Interactions; D006801:Humans; D008297:Male; D055641:Mathematical Concepts; D008954:Models, Biological; D011157:Population Dynamics; D012749:Sexually Transmitted Diseases / Q000635:transmission; D014774:Virulence
keywords: Adaptive dynamics; Evolutionary suicide; Extinction; Frequency-dependent incidence; Non-catastrophic bifurcation; Transcritical bifurcation; Virulence