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Epidemic Intelligence Service - Epidemiology Program Office
 
 

List of Case Studies

Student guides are provided for each case study. You must have Adobe Reader to read these files.

Teachers or trainers who wish to obtain instructor guides should email eis@cdc.gov and put “case study instructor guide request” in the subject line.  We do not provide instructor guides to students.

An Epidemic of Thyrotoxicosis

Student Guide #873-703 PDF document. Updated 2003. Outbreak with unknown etiology and mode of transmission, crossing state lines, 1985. A nice wrap-up study.

Learning Objectives

After completing this case study, the student should be able to

  1. List the key tasks involved in investigating epidemics of unknown cause;
  2. Describe the roles, responsibilities, and relationships of federal versus state public health agencies in a field investigation;
  3. Assign appropriate priority to key tasks during an investigation; and
  4. Describe jurisdictions of health agencies at various levels of government.

Cigarette Smoking and Lung Cancer

Student Guide #731-703 PDF document. Updated 2003. Based on the classic studies of Doll and Hill, 1950's. Addresses study design, interpretation of measures of association and impact of association.

Learning Objectives

After completing this case study, the student should be able to

  1. Discuss the elements of study design, and the advantages and disadvantages of case-control versus prospective cohort studies;
  2. Discuss some of the biases which might have affected these studies;
  3. Calculate a rate ratio, rate difference, odds ratio, and attributable risk percent;
  4. Interpret each measure and describe each measure’s use; and
  5. Review the criteria for causation.

Oral Contraceptive Use and Ovarian Cancer

Student Guide #811-703PDF document. Updated 2003. Multicenter case-control study, 1980–1982. Addresses bias, analysis of case-control studies.

Learning Objectives

After completing this case study, the student should be able to:

  1. Outline the sequence of an epidemiologic analysis;
  2. Discuss the biases of particular concern in case-control studies and ways to minimize their influence;
  3. Describe why and when to use crude and adjusted odds ratios and 95% confidence intervals, and how to interpret them; and
  4. Define and recognize effect modification and confounding.

Oswego: An Outbreak of Gastrointestinal Illness Following a Church Supper

Student Guide #401-303PDF document. Updated 2003. S. aureus outbreak among church picnic attendees, 1940. A classic, straightforward outbreak investigation in a defined population. Additional material: Compendium of Acute Foodborne and Waterborne DiseasesPDF document.

Learning Objectives

After completing this case study, the student should be able to

  1. Define the terms cluster, outbreak and epidemic;
  2. List the steps in the investigation of an outbreak;
  3. Draw, interpret and describe the value of the epidemic curve;
  4. Calculate and compare food-specific attack rates to identify possible vehicles;
  5. List reasons for investigating an outbreak that has apparently ended.

Paralytic Illness in Ababo

Student Guide #891-903.PDF document. Updated 2003.

Learning Objectives

After completing this case study, the student should be able to

  1. Define incidence, prevalence, and case-fatality rate;
  2. Define surveillance and identify the key features of a surveillance system;
  3. List the types of information that should be collected on a surveillance case report form;
  4. List the factors that can account for a change in the reported incidence of a disease;
  5. Define sensitivity of a surveillance system, and the effect of different case definitions on sensitivity.

Screening for Antibody to the Human Immunodeficiency Virus

Student Guide #871-703PDF document. Updated 2003. Hypothetical health department anticipating the release of the first HIV antibody test, 1985. The focus is on screening.

Learning Objectives

After completing this case study, the student should be able to

  1. Define and perform calculations of sensitivity, specificity, predictive-value positive and predictive-value negative;
  2. Describe the relationship between prevalence and predictive value;
  3. Discuss the trade-offs between sensitivity and specificity; and
  4. List the principles of a good screening program.

Suspected Legionnaires’ Disease in Bogalusa

Student Guide #912-303PDF document. Updated 2003. Community outbreak of Legionnaires' disease in Bogalusa, Louisiana in 1989. Ultimately traced to grocery store mist machine. Addresses the steps of a field investigation and a case-control study.

Learning Objectives

After completing this case study, the student should be able to

  1. Discuss the relationship between and roles of state-based and Atlanta-based EIS officers in a field investigation.
  2. Develop an epidemiologic case definition;
  3. Calculate power for a case-control study; and
  4. Describe different sources of controls for a community-based outbreak.

Surveillance for E. coli 0157:H7 - Information for Action

Student Guide #941-903 PDF document. Based on surveillance and investigation activities of the Oregon Health Division between 1986 and 1995.

Learning Objectives

After completing this case study, the student should be able to

  1. Discuss the process and criteria for placing a disease or condition on a state or national notifiable disease list;
  2. List the categories of information that should be included in a surveillance instrument;
  3. Summarize and interpret surveillance data;
  4. Recognize difficulties in balancing public health concerns with consumer and industry considerations in emerging issues.

Texarkana - Epidemic Measles in a Divided City

Student Guide #711-903 PDF document. Updated 2003.

Learning Objectives

After completing this case study, the student should be able to

  1. Discuss the advantages and disadvantages of using a sensitive and/or specific case definition in an epidemic investigation;
  2. Calculate vaccine efficacy and discuss its interpretation; and
  3. Discuss the advantages and limitations of selecting a specific age as the recommended target date for administering vaccinations.

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