Forensic Public Health: Epidemiological and Microbiological Investigations for Biosecurity

This chapter discusses how epidemiology integrated with laboratory science can be used to identify the source of diseases caused by microorganisms or toxins. Epidemiology is the study of how disease is distributed in populations and of the factors that influence this distribution. More broadly, it is the study of the distribution and determinants of health-related states or events in specified populations and application of this study to control health problems. Epidemiology is based on the premise that disease, illness, and ill health are not distributed randomly in a population and that individuals have certain characteristics (e.g., genetic) that interact with the environment and predispose to, or protect against, a variety of different diseases. The specific objectives of epidemiology are to (i) identify the etiology or cause of a disease and the factors that increase a person’s risk for disease; (ii) determine the extent of disease found in the community; (iii) study the natural history and prognosis of disease; (iv) evaluate new preventive and therapeutic measures and new modes of health care delivery; and (v) provide a foundation for developing public policy and regulations. A careful epidemiological investigation is required to determine whether an outbreak of infectious disease is due to intentional release of an agent or is naturally occurring. A number of molecular techniques have been developed for subtyping microbes that have been shown to complement the epidemiological investigation as well as identify related cases. As current subtyping methodologies evolve, applications and uses in the public health response to deliberate releases of biologic agents must be considered and applied.