caa a22 4500 477076165 CHVBK 20180405111439.0 cr unu---uuuuu 170330e19961201xx s 000 0 eng 10.1007/BF02515728 doi (NATIONALLICENCE)springer-10.1007/BF02515728 Kakehashi Masayuki Institute of Health Sciences, Hiroshima University School of Medicine, Kasumi, Minami-ku, 734, Hiroshima, Japan aut Populations and infectious diseases: Dynamics and evolution [Elektronische Daten] [Masayuki Kakehashi] The host-parasite or host-pathogen system was analyzed from dynamical and evolutionary viewpoints using simple mathematical models incorporating vertical transmission, immunity and its loss. We first analyzed a model without density regulation of host population. In the analysis on dynamics, the condition for the pathogen to work as a density regulating factor was obtained. In the analysis on evolution, criteria for the evolution of host and pathogen were proposed. These criteria implies that the evolution of hosts should result in an increase in infected host density, whereas the evolution of pathogens a decrease in susceptible host density. The direction of evolution at some parameters of host and that of pathogen were examined when the parameters were independently and freely changeable. Among the parameters, only reduction in additional mortality due to infection was the evolutionary trend common to both host and pathogen. In all the other parameters examined, trend of evolution predicted in host is reversed in pathogen. We then analyzed whether the obtained criteria still hold in models with density regulation of hosts. Using randomly generated parameter sets, we obtained the result that the criteria should hold very likely though they do not always hold. We discussed evolution of virulence when there is a constraint between the traits. Society of Population Ecology, 1996 infectious disease nationallicence population regulation nationallicence evolution nationallicence mathematical model nationallicence Researches on Population Ecology Springer-Verlag 38/2(1996-12-01), 203-210 0034-5466 38:2<203 1996 38 10144 https://doi.org/10.1007/BF02515728 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02515728 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Kakehashi Masayuki Institute of Health Sciences, Hiroshima University School of Medicine, Kasumi, Minami-ku, 734, Hiroshima, Japan aut NATIONALLICENCE 773 0- Researches on Population Ecology Springer-Verlag 38/2(1996-12-01), 203-210 0034-5466 38:2<203 1996 38 10144 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer