Introduction to Epidemiology 6th Edition by Ray M Merrill

Exercise 3

Would you undertake a case-control or a cohort study to investigate the source of thecyclosporiasis cases in New Jersey?Why?

Step 1 of 3

A cohort study includes investigations of people who do not belong to a distinct group and that do not have a common source of infection or disease in order to find out the cause and extent of a disease outbreak in that region over a particular period of time.

A case-control study includes investigations of a distinct group of individuals that share a common source of exposure; however some individuals are affected by this exposure (cases) and others are healthy individuals (controls). A retrospective study is carried out to identify the association between the risk factors and the disease in question.