Superinfection and the evolution of an initial asymptomatic stage. Author Chadi Saad-Roy, Bryan Grenfell, Simon Levin, Lorenzo Pellis, Helena Stage, P van den Driessche, Ned Wingreen Publication Year 2021 Type Journal Article Abstract Pathogens have evolved a variety of life-history strategies. An important strategy consists of successful transmission by an infected host before the appearance of symptoms, that is, while the host is still partially or fully asymptomatic. During this initial stage of infection, it is possible for another pathogen to superinfect an already infected host and replace the previously infecting pathogen. Here, we study the effect of superinfection during the first stage of an infection on the evolutionary dynamics of the degree to which the host is asymptomatic (host latency) in that same stage. We find that superinfection can lead to major differences in evolutionary behaviour. Most strikingly, the duration of immunity following infection can significantly influence pathogen evolutionary dynamics, whereas without superinfection the outcomes are independent of host immunity. For example, changes in host immunity can drive evolutionary transitions from a fully symptomatic to a fully asymptomatic first infection stage. Additionally, if superinfection relative to susceptible infection is strong enough, evolution can lead to a unique strategy of latency that corresponds to a local fitness minimum, and is therefore invasible by nearby mutants. Thus, this strategy is a branching point, and can lead to coexistence of pathogens with different latencies. Furthermore, in this new framework with superinfection, we also find that there can exist two interior singular strategies. Overall, new evolutionary outcomes can cascade from superinfection. Journal R Soc Open Sci Volume 8 Issue 1 Pages 202212 Date Published 2021 Jan ISSN Number 2054-5703 DOI 10.1098/rsos.202212 Alternate Journal R Soc Open Sci PMCID PMC7890506 PMID 33614103 PubMedPubMed CentralGoogle ScholarBibTeXEndNote X3 XML