The Benton-Franklin Health District is investigating a report of an adult who became sick from salmonella about a week ago, health officials said.  Investigators have not yet discovered the source of the salmonella, but are actively investigating any possible links between this Salmonella case and any other likely foodpoisoning cases recently.  

In other words, the epidemiological investigation into this salmonella illness is underway.  In addition to investigating whether any other confirmed Salmonella cases had similar food exposures to the infected individual, health officials will examine the actual DNA fingerprint of the particular strain of Salmonella involved.  This will allow them to better gauge the individual’s relationship not only to local outbreaks of foodborne or waterborne disease, but also outbreaks that are national in scope. 

Epidemiology is the study of factors affecting the health and illness of populations, and serves as the foundation and logic of interventions made in the interest of public health and preventive medicine. It is considered a cornerstone methodology of public health research, and is highly regarded in evidence-based medicine for identifying risk factors for disease and determining optimal treatment approaches to clinical practice. In the study of communicable and non-communicable diseases, the work of epidemiologists ranges from outbreak investigation to study design, data collection and analysis including the development of statistical models to test hypotheses and the documentation of results for submission to peer-reviewed journals. Epidemiologists also study the interaction of diseases in a population, a condition known as a syndemic. Epidemiologists rely on a number of other scientific disciplines such as biology (to better understand disease processes), biostatistics (the current raw information available), Geographic Information Science (to store data and map disease patterns) and social science disciplines (to better understand proximate and distal risk factors).

See http://en.wikipedia.org/wiki/Epidemiology