A group of researchers wants to investigate an outbreak of acute diarrhea that occurred in a coastal town in northern Massachusetts. Approximately 50 people who were from the town or were visiting the surrounding area had severe hemorrhagic diarrhea, in most cases requiring hospitalization for several days. A fatal case was reported. The researchers believe that the outbreak is related to seafood prepared at one of the coastal restaurants. Which of the following study designs is most appropriate to test this hypothesis?
A)Case-control study
B)Correlational study
C)Cross-sectional study
D)Longitudinal study
E)Randomized clinical trial

Question

A group of researchers wants to investigate an outbreak of acute diarrhea that occurred in a coastal town in northern Massachusetts.  Approximately 50 people who were from the town or were visiting the surrounding area had severe hemorrhagic diarrhea, in most cases requiring hospitalization for several days.  A fatal case was reported.  The researchers believe that the outbreak is related to seafood prepared at one of the coastal restaurants.  Which of the following study designs is most appropriate to test this hypothesis?
A)Case-control study
B)Correlational study
C)Cross-sectional study
D)Longitudinal study
E)Randomized clinical trial

Quizplus · Accepted Answer

Explanation: 11ec2b69_c0e0_c85a_8f63_45063586412e_MD0005_00 A case-control study design is appropriate to investigate an acute infectious disease outbreak as it explores the association between exposure and disease, can be conducted when the number of affected subjects is small, and generally allows for quick localization of the outbreak source. A case definition is constructed. Subjects who developed the disease (satisfied the case definition) should be questioned about their recent exposures (eg, eating a particular dish at a particular restaurant), and unaffected subjects should be chosen as controls to reflect the exposure experience of the general population. If cases are more likely to be exposed than controls (ie, statistically significant odds ratio >1), then an association between exposure and disease can be established. Correlational studies attempt to measure associations between multiple variables and are generally conducted by natural observation, surveying, or archival research. They help develop but not test hypotheses. Because many combinations of variables are examined, there is a risk (due to chance alone) of finding an association that may not actually be true (Choice B). A longitudinal study is a type of observational correlational study in which repeat measurements of the same variables are taken over a prolonged period (Choice D). A case-control study design is better suited for outbreak investigation as it focuses on a specific disease and associated exposures. (Choice C) Cross-sectional studies begin with risk factor/exposure status (eg, ate/did not eat seafood at a coastal restaurant) and compare disease prevalence to provide a snapshot. They are helpful in determining prevalence rather than investigating outbreaks or etiologies. (Choice E) A clinical trial in which a group of individuals is randomly assigned to eat seafood prepared at coastal restaurants would be neither appropriate nor ethical. Educational objective: A case-control study is the most appropriate study design to investigate an outbreak of an acute infectious disease. It generally allows for quick localization of the outbreak source.

A Group of Researchers Wants to Investigate an Outbreak of Acute