Using Case-Case Study Designs to Study Foodborne Enteric Infections

Abstract

Case-control studies are the traditional ways in which foodborne enteric diseases are studied and outbreaks are investigated. This method has some significant limitations and biases for diseases with low efficiency reporting rates, such as Campylobacter, a common foodborne disease. Case-case methodologies have been explored for these studies but have been implemented without any clear strategy. This dissertation aims to first, determine the common risk factors for Campylobacter in Arizona using the traditional case-control study design, second, to systematically compare case-case studies to the more common case-control studies, and third, to simultaneously compare the results of a community outbreak of Campylobacter using both case-control and case-case study designs. Results from these studies identified some unique risk factors for routine Campylobacter infection in Arizona that will be used to enhance surveillance for the disease in the state. A systematic review of case-case studies used for enteric diseases found that there are specific recommendations that can be put into place in determining what comparison cases should be selected based on the primary aims and goals of the study. Finally, the results of the simultaneous case-case and case-control studies of a Campylobacter outbreak showed that these methods may work best in conjunction with one another and in doing so, the most accurate depiction of the source of infection can be determined.