Case Control, Cohort, and Other Studies
Although foodborne outbreaks are common, approximately 95% of foodborne infections occur as sporadic (non-outbreak) cases. It is difficult to determine what specific exposure caused a person with a sporadic infection to become ill; however, risk factors can be explored through population-based studies. Studies are conducted to examine the importance of various possible risky exposures (such as specific foods) and practices (such as food preparation and handling practices) as contributors to illness caused by specific pathogens.
Cases of infections with the pathogens under study are ascertained through routine FoodNet surveillance. FoodNet staff contact case-patients and healthy controls (if a case-control study is being performed) to administer a questionnaire. Studies may also include molecular subtyping or antimicrobial resistance testing of patient isolates.
Study summaries, links to study protocols and questionnaires, and article references can be accessed by clicking on the pathogen topic links below.