The above body of ecological theory and observations involving specific emerging infectious disease cases suggests a causal schema that links ecological phenomena on the scale of pathogen transmission and evolution to regional and global transformations. This is represented by Figure 1 , focusing on the role of demographic and societal factors in disease emergence (shown in Table 1 ). This schema is constructed using the generally adopted view of human-environment interaction in which the impact of human population and technology is taken as the driving force, or ultimate cause. Clark et al. (25) elaborate on this in their seminal treatment on global and regional change. Here, the combination of population, technological capacity, and sociocultural organization act as the system drivers of regional environmental change. These and 'mitigating' forces are in turn influenced by 'human behavior', referring to patterns of actions and the rationales giving rise to them. Broadly speaking, these forces and their affects on ecosystems represent the 'ecological factors' in social-ecological systems, while human behavior represents the 'social factors' for the purposes of discussion.