However, the development and application of systems theory independently of and largely outside the realm of mainstream systems ecology (47) shows significant promise in providing a basis for more systematic interpretation of the role of ecosystem change in disease emergence. Recent thinking draws in particular on the application of the theory of 'complex adaptive systems' to ecological systems in which ecosystems are represented as scaled, self-organizing, far from equilibrium, evolutionary, and non-linear (6) . Organization, diversity, and resilience are important 'emerging' properties of complex systems-often equated with a 'healthy' state. 'Surprise', or qualitative disagreements of system behavior with a priori expectations, is another property (48) . Their association with loss of system resilience and increased vulnerability applies both to increasing inflexible social systems 'managing' and attempting to 'control' natural variables (i.e., vectors, pathogens) and that of the ecosystems whose component variables (e.g., vector and pathogen populations) are targeted for management or control.