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Lesson 1: Introduction to Epidemiology

Self-Assessment Quiz

Now that you have read Lesson 1 and have completed the exercises, you should be ready to take the self-assessment quiz. This quiz is designed to help you assess how well you have learned the content of this lesson. You may refer to the lesson text whenever you are unsure of the answer.

Unless instructed otherwise, choose ALL correct answers for each question.


  1. In the definition of epidemiology, "distribution" refers to:
    1. Who
    2. When
    3. Where
    4. Why
  2. In the definition of epidemiology, "determinants" generally includes:
    1. Agents
    2. Causes
    3. Control measures
    4. Risk factors
    5. Sources
  3. Epidemiology, as defined in this lesson, would include which of the following activities?
    1. Describing the demographic characteristics of persons with acute aflatoxin poisoning in District A
    2. Prescribing an antibiotic to treat a patient with community-acquired methicillin-resistantStaphylococcus aureus infection
    3. Comparing the family history, amount of exercise, and eating habits of those with and without newly diagnosed diabetes
    4. Recommending that a restaurant be closed after implicating it as the source of a hepatitis A outbreak
  4. John Snow's investigation of cholera is considered a model for epidemiologic field investigations because it included a:
    1. Biologically plausible hypothesis
    2. Comparison of a health outcome among exposed and unexposed groups
    3. Multivariate statistical model
    4. Spot map
    5. Recommendation for public health action
  5. Public health surveillance includes which of the following activities:
    1. Diagnosing whether a case of encephalitis is actually due to West Nile virus infection
    2. Soliciting case reports of persons with symptoms compatible with SARs from local hospitals
    3. Creating graphs of the number of dog bites by week and neighborhood
    4. Writing a report on trends in seat belt use to share with the state legislature
    5. Disseminating educational materials about ways people can reduce their risk of Lyme disease
  6. The hallmark feature of an analytic epidemiologic study is: (Choose one best answer)
    1. Use of an appropriate comparison group
    2. Laboratory confirmation of the diagnosis
    3. Publication in a peer-reviewed journal
    4. Statistical analysis using logistic regression
  7. A number of passengers on a cruise ship from Puerto Rico to the Panama Canal have recently developed a gastrointestinal illness compatible with norovirus (formerly called Norwalk-like virus). Testing for norovirus is not readily available in any nearby island, and the test takes several days even where available. Assuming you are the epidemiologist called on to board the ship and investigate this possible outbreak, your case definition should include, at a minimum: (Choose one best answer)
    1. Clinical criteria, plus specification of time, place, and person
    2. Clinical features, plus the exposure(s) you most suspect
    3. Suspect cases
    4. The nationally agreed standard case definition for disease reporting
  8. A specific case definition is one that:
    1. Is likely to include only (or mostly) true cases
    2. Is considered "loose" or "broad"
    3. Will include more cases than asensitive case definition
    4. May exclude mild cases
  9. Comparing numbers and rates of illness in a community, rates are preferred for: (Choose one best answer)
    1. Conducting surveillance for communicable diseases
    2. Deciding how many doses of immune globulin are needed
    3. Estimating subgroups at highest risk
    4. Telling physicians which strain of influenza is most prevalent
  10. For the cruise ship scenario described in Question 7, how would you display the time course of the outbreak? (Choose one best answer)
    1. Endemic curve
    2. Epidemic curve
    3. Seasonal trend
    4. Secular trend
  11. For the cruise ship scenario described in Question 7, if you suspected that the norovirus may have been transmitted by ice made or served aboard ship, how might you display "place"?
    1. Spot map by assigned dinner seating location
    2. Spot map by cabin
    3. Shaded map of United States by state of residence
    4. Shaded map by whether passenger consumed ship's ice or not
  12. Which variables might you include in characterizing the outbreak described in Question 7 by person?
    1. Age of passenger
    2. Detailed food history (what person ate) while aboard ship
    3. Status as passenger or crew
    4. Symptoms
  13. When analyzing surveillance data by age, which of the following age groups is preferred? (Choose one best answer)
    1. 1-year age groups
    2. 5-year age groups
    3. 10-year age groups
    4. Depends on the disease
  14. A study in which children are randomly assigned to receive either a newly formulated vaccine or the currently available vaccine, and are followed to monitor for side effects and effectiveness of each vaccine, is an example of which type of study?
    1. Experimental
    2. Observational
    3. Cohort
    4. Case-control
    5. Clinical trial
  15. The Iowa Women's Health Study, in which researchers enrolled 41,837 women in 1986 and collected exposure and lifestyle information to assess the relationship between these factors and subsequent occurrence of cancer, is an example of which type(s) of study?
    1. Experimental
    2. Observational
    3. Cohort
    4. Case-control
    5. Clinical trial
  16. British investigators conducted a study to compare measles-mumps-rubella (MMR) vaccine history among 1,294 children with pervasive development disorder (e.g., autism and Asperger's syndrome) and 4,469 children without such disorders. (They found no association.) This is an example of which type(s) of study?
    1. Experimental
    2. Observational
    3. Cohort
    4. Case-control
    5. Clinical trial
  17. A cohort study differs from a case-control study in that:
    1. Subjects are enrolled or categorized on the basis of their exposure status in a cohort study but not in a case-control study
    2. Subjects are asked about their exposure status in a cohort study but not in a case-control study
    3. Cohort studies require many years to conduct, but case-control studies do not
    4. Cohort studies are conducted to investigate chronic diseases, case-control studies are used for infectious diseases
  18. A key feature of a cross-sectional study is that:
    1. It usually provides information on prevalence rather than incidence
    2. It is limited to health exposures and behaviors rather than health outcomes
    3. It is more useful for descriptive epidemiology than it is for analytic epidemiology
    4. It is synonymous with survey
  19. The epidemiologic triad of disease causation refers to: (Choose one best answer)
    1. Agent, host, environment
    2. Time, place, person
    3. Source, mode of transmission, susceptible host
    4. John Snow, Robert Koch, Kenneth Rothman
  20. For each of the following, identify the appropriate letter from the time line in Figure 1.27 representing the natural history of disease.

    Figure 1.27 Natural History of Disease Timeline

    Match the occurrence to the appropriate stage.

    Image Description

    1. ____ Onset of symptoms
    2. ____ Usual time of diagnosis
    3. ____ Exposure
  21. A reservoir of an infectious agent can be:
    1. An asymptomatic human
    2. A symptomatic human
    3. An animal
    4. The environment
  22. Indirect transmission includes which of the following?
    1. Droplet spread
    2. Mosquito-borne
    3. Foodborne
    4. Doorknobs or toilet seats
  23. Disease control measures are generally directed at which of the following?
    1. Eliminating the reservoir
    2. Eliminating the vector
    3. Eliminating the host
    4. Interrupting mode of transmission
    5. Reducing host susceptibility
  24. Which term best describes the pattern of occurrence of the three diseases noted below in a single area?
    1. Endemic
    2. Outbreak
    3. Pandemic
    4. Sporadic
    1. ____ Disease 1: usually 40–50 cases per week; last week, 48 cases
    2. ____ Disease 2: fewer than 10 cases per year; last week, 1 case
    3. ____ Disease 3: usually no more than 2–4 cases per week; last week, 13 cases
  25. A propagated epidemic is usually the result of what type of exposure?
    1. Point source
    2. Continuous common source
    3. Intermittent common source
    4. Person-to-person

Image Description

Figure 1.27

Description: Item "A" occurs between the stage of susceptibility and the stage of subclinical disease. Item "B" occurs during the stage of subclinical disease. Item "C" occurs between the stage of subclinical disease and the stage of clinical disease. Item "D" occurs shortly after the stage of clinical disease begins. Item "E" occurs at the end of the stage of clinical disease. Return to text.