The Evolution of Virulence: A Unifying Link between Parasitology and Ecology

作者：Paul W. Ewald · 发表于：Journal of Parasitology · 年份：1995 · DOI：10.2307/3283951 · 被引用次数：197 · 研究领域：Evolution and Genetic Dynamics、Parasite Biology and Host Interactions、Evolutionary Game Theory and Cooperation

For most of the past century, the in parasitology and epidemiology has been that a parasite is a benign parasite (parasites being defined broadly to include multicellular, unicellular, and subcellular organisms). This view became firmly entrenched during the second quarter of this century (Smith, 1934; Swellengrebel, 1940). Although objections were raised during the middle decades of this century (Ball, 1943; Cockburn, 1963), they had little impact in the face of the more aesthetically appealing paradigm, which advocated evolution toward balanced, stable associations in which parasites succeeded through peaceful coexistence with their hosts. The problem with this view is that natural selection does not necessarily favor peaceful coexistence. Rather, it favors those genetic instructions that are passed on preferentially as a result of the characteristics they encode. If instructions that cause their bearer to exploit host resources more fully are more successfully passed into future generations as a result of that exploitation, then adaptation to the host will be associated with increased exploitation of the host. Insofar as increased exploitation causes increased harm, evolutionary adaptation to the host will result in increased harm to the host. This conclusion was reached independently by several investigators during the last quarter of the 20th century (Ewald, 1980, 1983; Price, 1980; Levin and Pimentel, 1981; Anderson and May, 1982)--in contrast to the situation during mi...