Tsukushi Kamiya, Nicole Mideo, Samuel AlizonPlease use the format "First name initials family name" as in "Marie S. Curie, Niels H. D. Bohr, Albert Einstein, John R. R. Tolkien, Donna T. Strickland"
Many components of the host-parasite interaction have been shown to affect the way virulence, that is parasite induced harm to the host, evolves. However, co-evolution of multiple traits is often neglected. We explore how an immunosuppressive mechanism of parasites affects and co-evolves with virulence through multiple infections. Applying the adaptive dynamics framework to epidemiological models with co-infection, we show that immunosuppression elevates the evolutionarily stable (ES) virulence through epidemiological feedbacks. We explore the co-evolution of the two parasite traits across different extrinsic mortality conditions, and find that the peak ES virulence occurs at an intermediate level of background host mortality when immunosuppression is considered. The highest co-ES virulence is achieved at the intermediate level of background mortality which we interpret by considering the abundances of each host types. In addition, we find that immunosuppression evolution is influenced considerably by the precise shape of the trade-offs determining the cost and benefit of immunosuppression. These results demonstrate that the ES virulence is shaped by immunosuppression, while highlighting that the evolution of immune evasion mechanisms deserves further research attention.
multiple infections, immunosuppression, virulence, epidemiology, evolution
Evolutionary Applications, Evolutionary Dynamics, Evolutionary Ecology, Evolutionary Epidemiology, Evolutionary Theory
