Trophic Cascades and Disease Ecology

Excerpt

The ecology of infectious disease is an important, growing sub-discipline of ecology that combines field studies, epidemiology, molecular approaches, and modeling to understand interactions among wildlife hosts, vectors, and pathogens, and to better forecast risk of disease. At its core, disease ecology is population and community ecology, and many of the concepts and paradigms of these well-established sub-disciplines can be effectively applied to studies of the ecology of infectious disease. Several recent articles have attempted to place ecological studies of disease systems in the context of food-web ecology. Yates et al. (2002), building upon results and arguments in Parmenter et al. (1999), proposed a “trophic-cascade hypothesis” to explain how climatic variation affects the probability of outbreaks of hantavirus pulmonary syndrome (HPS), a disease spread by small rodents, in the southwestern United States (also see Enscore et al., 2002; Davis et al., 2005). In this scenario, mild weather conditions increase primary production and the availability of food for small rodents, resulting in higher rodent population density and, eventually, increased risk of HPS transmission to humans in rural areas (see Brown and Ernest, 2000, for an alternative view). Collinge et al. (2005), in a recent article in EcoHealth, tested the generality of this “trophic-cascade hypothesis” as an explanation for outbreaks of plague in prairie-dog colonies in Colorado and Montana. …