Epidemiology Midterm, Spring 2003

Coverage: Chap 1, Chap 2, Chap 3, Chap 6, Chap 8, Bioterrorism (Anthrax) Case Study Please write your name on the back of the last page in the usual (upper right) location.

Multiple Choice and True/False Questions. Please use a scantron (provided) to record your answers. For multiple choice [M/C] questions, select the single best response. For true/false [T/F], choose mark “a” for true and “b” for false. Read each question carefully.

1. [T/F]: The standard medical definition of health is the absence of disease.

2. [T/F]: The WHO definition of health addresses “physical, mental, spiritual, and social well-being.”

3. [T/F]: Specific definitions of health might be culturally specific.

4. [T/F]: Illness is a social dysfunction.

5. [T/F]: “Mortality” refers to death.

6. [T/F]: “Morbidity” refers to disability and disease.

7. [T/F]: The word “epidemic” means the normal level of disease occurrence in a population.

8. [T/F]: The word “pandemic” is an epidemic simultaneously affecting populations on several different continents.

9. [T/F]: The leading cause of death in the US is cardiovascular disease.

10. [T/F]: The second leading cause of death in the US is cancer.

11. [T/F]: External causes of death (e.g., accidents) are relatively unimportant in the United States.

12. [M/C]: John Snow’s investigations occurred in the (a) 1650s, (b) 1750s, (c) 1850s, (d) 1950s.

13. [M/C]: The first person ever to systematically study morbidity and mortality on a population basis (in 17th century England) was (a) John Snow (b) John Graunt (c) Richard Doll (d) David Lilienfeld.

14. [T/F]: One hundred years ago, the major causes of death in the United States were chronic and contagious.

15. [T/F]: Over the past 50 years, age-adjusted cardiovascular disease mortality rates have increased.

16. [T/F]: Over the past 50 years, age-adjusted cancer mortality rates have been more-or-less constant.

Page 1 of C:\DATA\HS161\ex1-s03.wpd 17. [T/F]: Over the past 100 years, life expectancy has increased dramatically in all groups except African American men.

18. [T/F]: The stage of subclinical disease begins with first symptoms.

19. [T/F]: Tertiary prevention occurs during the subclinical stage of disease.

20. [T/F]: The “spectrum of disease” refers to the broad range of manifestations and severities of an illness or disease.

21. [T/F]: The “iceberg phenomenon” describes the situation in which a large percentage of cases go undetected.

22. [T/F]: HIV is a necessary cause of AIDS.

23. [T/F]: HIV is a sufficient cause of AIDS.

24. [M/C]: This causal model addresses how direct and indirect causes form complex inter- connected networks: (a) causal pie model (b) risk factor model (c) causal web model.

25. [T/F]: The ecology of disease considers agent, host, and environmental factors as causes.

26. [M/C]: The general term used for the habitat in which the agent multiplies and grows is the (a) reservoir (b) carrier (c) portal (d) host.

27. [M/C]: The general term used for host factors that alter the likelihood of disease and infection once the agent is encountered is: (a) transmission (b) zoonosis (c) reservoir (d) immunity.

28. [M/C]: The Broad Street pump cholera outbreak of 1854 was this type of epidemic: (a) serial (b) point source (c) propagating.

29. [M/C]: The agent that causes malaria is a (a) virus (b) bacteria, (c) fungus, (d) protozoan.

30. [M/C]: The agent that causes anthrax is a (a) virus (b) bacteria, (c) fungus, (d) protozoan.

31. [T/F]: Anthrax is normally a zoonotic disease.

32. [T/F]: Anthrax is easily transmitted from person-to-person.

33. [T/F]: Respiratory anthrax is often fatal.

34. [T/F]: Cutaneous anthrax is often fatal.

35. [M/C]: Environmental clean-up of anthrax difficult because (a) the agent replicates in the environment (b) the agent is difficult to locate (c) the agent encapsulates.

Page 2 of C:\DATA\HS161\ex1-s03.wpd 36. [M/C]: This type of transmission requires proximity to an infected host or its secretions: (a) transmission by contact (b) vehicle borne transmission (c) vector borne transmission.

37. When an agents multiplies in a vector the vector is said to be (a) mechanical (b) developmental (c) propagative.

38. [T/F]: All of the following forms of innate immunity except (a) physical barriers to infection (e.g., skin), (b) chemical barriers to infection (e.g., acidity of the stomach), (c) non-specific immune cells (e.g., macrophages), (d) antibodies.

39. [T/F]: Vaccination requires an active response on the part of the host’s immune system.

40. [T/F]: Modified live vaccines are composed of non-virulent strains of the agents that cause subclinical infections.

41. [M/C]: Receipt of immune-serum after exposure to an agent is a form of (a) vaccination (b) passive immunization (c) active immunization.

42. [M/C]: Human that harbor a specific agent while manifesting no signs or symptoms are called (a) portals (b) vectors (c) carriers (d) none of the above.

43. [M/C]: Sexually transmitted diseases normally have this portal of entry: (a) urogenital (b) respiratory (c) conjunctival (d) gastrointestinal.

44. [M/C]: This type of cell regulates the immune response: (a) T lymphocytes(b) B lymphocytes(c) macrophages(d) NK cells

45. [M/C]: This is "the proportion of people in a population who are cases at a particular point in time": (a) incidence rate (b) incidence risk (c) prevalence (d) risk ratio.

46. [M/C]: This is "the proportion of people at risk in a cohort who develop a disease over a set period of time": (a) incidence rate (b) incidence risk (c) prevalence (d) risk ratio.

47. [T /F]: A cohort is a closed group of people in which people do not enter or leave, other than by death.

48. [M/C]: If the incidence rate of a disease remains constant but the death rate of the disease decreases, then the prevalence of the disease will (a) increase (b) decrease (c) remain the same.

49. Over long periods of time, what happens to the size of a cohort? (a) it increases (b) it decreases (c) it may increase, decrease or remain the same.

50. Over long periods of time, what happens to the size of an open population? (a) it increases (b) it decreases (c) it may increase, decrease or remain the same.

Page 3 of C:\DATA\HS161\ex1-s03.wpd 51. This epidemiologic statistic quantifies the effect of an exposure in absolute terms: (a) risk ratio (b) risk difference (c) attributable fraction (d) incidence rate.

52. This epidemiologic statistic quantifies the expected fractional reduction in cases with removal of the exposure from the population or group: (a) risk ratio (b) risk difference (c) attributable fraction (d) incidence rate.

53. An epidemiologists says "the exposure doubles the risk of the disease." The epidemiologist is speaking of a (a) risk ratio (b) risk difference (c) attributable fraction (d) incidence rate.

54. An epidemiologists says "an exposure increases risk by 1%. The epidemiologist is speaking of a (a) risk ratio (b) risk difference (c) attributable fraction (d) incidence rate.

NARRATIVE RESPONSES AND SHORT ANSWER. Please answer directly on the page..

55. How does “contamination” differ from “infection”?

56. List the three portals of entry for anthrax:

a. ______

b. ______

c. ______

57. List the four stages in the natural history of a disease:

a. ______

b. ______

c. ______

d. ______

Page 4 of C:\DATA\HS161\ex1-s03.wpd CALCULATIONS - Show intermediate calculations. Draw a square around final answers.

58. A cohort begins with 3,000 men. Of these, 500 have cardiovascular disease. The remaining 2,500 men are followed for two years. During this period, 250 develop cardiovascular disease. Based on this information:

(A) What is the prevalence of cardiovascular disease at the beginning of the study? [3 pts]

(B) What is the two-year risk (cumulative incidence) of cardiovascular disease in this cohort? [3 pts]

Page 5 of C:\DATA\HS161\ex1-s03.wpd 59. Vital statistics for a state are as follows:

Population size (midyear) 22,126,000 Number of live births 406,123

Number of deaths 335,688

Number of deaths in infants (< 1 year of 4,120 age)

(A) What is the crude birth rate per 1000? [3 pts]

(B) What is the crude death rate per 1000?[3 pts]

Page 6 of C:\DATA\HS161\ex1-s03.wpd 60. An epidemiologic study is conducted to learn about the relation between exposure E and disease D. Ten (10) cases occur in the 475 people in the exposed group. Fifteen (15) cases occur in the 2166 people in the non-exposed group.

(A) Calculate the risk of disease in the exposed group. (Carry four decimal places.) [3 pts]

(B) Calculate the risk of disease in the non-exposed group. [3 pts]

(D) Interpret the above risk ratio. Please use proper grammar. [2 pt]

(D) Interpret the above risk difference. [2 pts]

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