title: Co-infection and super-infection models in evolutionary epidemiology.
abstract: Multiple infections are intensively studied because of their consequences for the health of the host but also because they can radically alter the selective pressures acting on parasites. I discuss how multiple infections have been modelled in evolutionary epidemiology. First, I briefly mention within-host models, which are at the root of these epidemiological models. Then, I present the super-infection framework, with an original focus on how the definition of the super-infection function can lead to evolutionary branching. There are several co-infection models and, for each of them, I briefly go through the underlying mathematics (especially the invasion fitness of a mutant strain) and I discuss the biological assumptions they make and the questions they consequently may ask. In particular, I show that a widely used co-infection model should not be invoked for invasion analyses because it confers a frequency-dependent advantage to rare neutral mutants. Finally, I present more recent frameworks, such as the Price equation framework in epidemiology, that can account for increased parasite diversity. To conclude, I discuss some perspectives for the study of multiple infections in evolutionary epidemiology.
authors: Laboratoire MIVEGEC (UMR CNRS 5290, UR IRD 224, UM1, UM2) , 911 avenue Agropolis, BP 64501, 34394 Montpellier Cedex 5 , France.
authors: Samuel
authors: S
authors: Alizon
keywords: adaptive dynamics; epidemiology; evolutionary biology; multiple infections; trade-offs; virulence