ABSTRACT
Conventional epidemiology recognizes that epidemics, like individual infections and injuries, arise in a specific ecological context. Epidemics are complex, contingent processes that develop through the interaction of characteristics of the pathogen, the vulnerable population, and environmental factors (Stillwaggon 2009). Whatever the proximate cause of infection or injury, epidemiology examines the multiple factors that influence both individual risk and the vulnerability of populations. In the last half-century, advances in microbiology and medical interventions as well as changes in the political and economic climate have shifted the emphasis of medical research to individual-level rather than population-level factors in theories of disease causation (Rose 1985; Schwartz and Carpenter 1999; Stillwaggon 2006; Susser 1985). Nevertheless, the standard epidemiological approach encompasses the ecological context of both individual and population risk.
