Chapter 2 Review Questions KEY 

�2.1 NATURAL HISTORY OF DISEASE

  1. Susceptibility, preclinical, clinical,  recovery/disability/death
  2. See text.
  3. Primary prevention - prevent new occurrences. Secondary prevention - delay onset or decrease severity. Tertiary prevention - minimize the progression of disease or prevent sequelae. 
  4. The agent multiplies within the host.
  5. Latency
  6. tuberculosis, AIDS, leprosy.
  7. Mammography is a form of secondary prevention because it picks up disease after its been initiated but before it is clinically evident.
  8. Causal interdependence means that a disease will express itself only when complementary components combine to create sufficiency. 
  9.  Low Ca++ diet, osteoporosis, sedation, slippery surface 
  10. See p. 35

�2.2 SPECTRUM OF DISEASE AND THE ICEBERG

  1. spectrum of disease.
  2. Student choice . . .  
  3. Epidemiologic iceberg 

�2.3 CAUSAL CONCEPTS

  1. Any predecessor without which disease would not have occurred or would have occurred at a later time (all other things being equal).
  2. Measles virus is necessary but not sufficient to cause measles. 
  3. (a) The agent is present in every case [necessity] (b) The agent does not cause any other disease [specificity] (c) The agent can be isolated in pure culture and can initiate the disease in a susceptible  host 
  4. . . . when disease becomes inevitable.
  5. (E + F)
  6. E
  7. True
  8. Phenylkenouria is both a genetic disease and environmental disease. The genetic disorder involves a lack of the enzyme phenylalanine hydroxylase. The environmental component requires the presence of dietary phenylketones.
  9. The prevalence of phenylkenouria would be equal to the prevalence of the genetic abnormality that determine the condition. 
  10. Zero
  11. A direct cause is a causal factor that causes pathology within the individual.
  12. An indirect cause is not directly related to pathologic event (in the body) but is instead interconnected to other factors.
  13. Biological, physical, and chemical
  14. nutritive, poisons, drugs, allergens
  15. heat, light, radiation, noise, vibration, and objects that cause trauma
  16. Infectivity = ability to infect; pathogenicity = ability to cause disease; virulence = ability to cause severe disease
  17. Agent, host, and environmental factors are in ecological balancing in a population. Environmental factors that favor the agent lead to more disease. Enironmental factors that harm host resistance lead to disease. See the text for a better explanation. 
  18. Definitions (a) = Virulence, (b) = Sufficient constellation, (c) = Cause, (d) = Infectivity, (e) = Causal web, (f) = Pathogenicity, (g) = Necessary cause

�2.4 EPIDEMIOLOGIC VARIABLES

  1. what, why, when, how, where, who
  2. False. If there were so, there would be no point in describing their distribution according to person, place, and time criteria. 
  3. place, and time.
  4. See Table 2.3 (p. 49).
  5. person
  6. See Table 2.4 (p. 51).
  7. Studies show that Japanese-American women develop breast cancer rates typical of American women after several generations of acculturation. 
  8. (a) propagating epidemic (b) point epidemic (c)  endemic (d) sporadic