(1) Epidemiology and Public Health are both concerned with the prevention of disease and the promotion of health in populations. How do they differ? [3]
ANS: Epidemiology is mostly a ["study of"]. Public health is largely an ["activity or organized effort"]
(2) List the three most common causes of death in the United States, as of 1992, in their correct order: [3]
ANS: (A) Heart disease (B) Cancer (C) Injuries / External Cause
(3) How do the above three diseases differ from the primary causes of death that occurred at the turn of the last century? [2]
ANS: The most common causes of death today are [chronic] and [non-contagious]. Most of the common causes of death at the turn of the prior century were [acute] and [contagious] (the exception being TB, which is chronic and contagious).
(4) Define "epidemic." [2]
ANS: An epidemic is a clear excess above normalcy of disease or disease-related condition in a definable population.
(5) Define "endemic." [2]
ANS: Endemic means that the disease is occurring at is usual or expected rate.
(6) Define "morbidity." [2]
ANS: Morbidity mean related to disease or disability.
(7) Name the physician who removed the handle from the Broad Street pump. [1]
ANS: John Snow
(8) List a synonym for "incubation period." [1]
ANS: Any of the following: latent period, induction period, or preclinical stage of disease
(9) Match the definitions below with one of the following terms: (A) contributing cause; (B) natural history of disease; (C) necessary cause; (D) primary prevention; (E) secondary prevention; (F) stage of clinical disease; (G) stage of susceptibility; (H) stage of subclinical disease; (I) sufficient cause (J) tertiary prevention
Definition | Term |
A causal factor that is neither necessary nor sufficient, but increases the likelihood of disease, all other things being equal. | (A) contributing cause |
Any factor that must be present for the disease to occur. | (C) necessary cause |
Any factor or, more commonly a constellation of factors, that inevitably lead to the disease | (I) sufficient cause |
Preventive measures that occur during the stage of subclinical disease, intended to delay the onset of disease or reduce its duration or severity | (E) secondary prevention |
Preventive measures aimed at the stage of susceptibility, intended to reduce new occurrences of disease. | (D) primary prevention |
Preventive measures that are intended to reduce the complications and disabilities associated with an ongoing disease. | (J) tertiary prevention |
The stage of disease the follows exposure to the agent but is before symptoms are apparent. | (H) stage of subclinical disease |
The stage in the natural history of a disease that precedes exposure to the causal agent. | (G) stage of susceptibility |
The progression of a disease in an individual over time. | (B) natural history of disease |
The stage of disease associated with signs and symptoms | (F) stage of clinical disease |
(10) Distinguish between a "risk indicator" and "risk factor." [2]
ANS: A risk indicator is a factor that is statistically associated with a disease but is not necessary causal. A risk factor is truly causal.
(11) The habitat or environment in which an infectious agent lives and multiplies is called its ________________________.
ANS: reservoir
(12) All infectious diseases are associated with infections but not all infections are associated with disease. Please explain. [2]
ANS: Infections can be asymptomatic.
(13) List four of the five elements of the infectious disease process [5]
ANS: (A) agent (B) reservoir (C) portals (D) transmission (E) host immunity
(14) List two examples of portals. [2]
ANS: Any two of the following: respiratory tract, conjunctiva, urogenital tract, gastrointestinal tract, placenta.
(15) Provide an example of a physical barrier to infection. [1]
ANS: Any of following: skin, mucosal linings, mucus sheaths, respiratory tract cilia, cough and gag reflex
(16) Provide an example of a chemical barrier to infection. [1]
ANS: Any of the following: acidity of stomach and vagina, enzymes in saliva and GI tract, lipids, interferons, and other miscellaneous biologically active substances.
(17) How does a modified live vaccine differ from a killed vaccine? [2]
ANS: Modified live vaccines are composed of non-virulent strains of the agent, modified to be nonpathogenic. "Killed" vaccines are agent proteins that are incapable of replicating themselves.
(18) Match the definitions below with the following terms
- sign
- symptom
- test.
___________ The subjective perceptions of disease made on the part of the patient.
___________ A measures of physiologic or immunologic function.
___________ An observation indicative of a disease made by an examiner.
(19) Define reproducibility. [2]
ANS: [repeatability / consistency]
(20) A kappa statistic of 1 indicates (select best response):
ANS: (A)
(21) This problem is similar to the problems in the case study in which we backfilled a sensitivity / specificity table in order to determine the predictive value positive of a test in a population. Suppose, we start with a population of 10,000 individuals in which the prevalence of disease is 5% (0.05). A test that is 96% sensitive (SEN = 0.96) and 98% specificity (SPEC = 0.98) is used to uncover latent infection in the population. Based on this information, fill in all boxes with "______", below. (Use the blank back of the prior page to show your work.)
D+ | D- | ||
T+ | 480_____ | 190_____ | 670_____ |
T- | 20_____ | 9310_____ | 9,330_____ |
500_____ | 9,500_____ | 10,000 |
ANS:
m1 = (N)(P) = 500
m2 = N - m1 = 10,000 - 500 = 9,500
TP = (SEN)(m1) = (.96)(500) = 480
FN = m1 - TP = 500 - 480 = 20
TN = (SPEC)(m2) = (.98)(9500) = 9,310
FP = m2 - TN = 9500 - 9310 = 190
n1 = TP + FP = 480 + 190 = 670
n2 = FN + TN = 20 + 9310 = 9330
(22) The predictive value positive of the above test in the above population is = __________
ANS: PVP = (TP) / n1 = 480 / 670 = 0.7164
(23) The predictive value negative of the above test in the above population = __________
ANS: PVN = (TN) / n2 = 9310 / 9330 = 0.9979
(24) Do you think it would be safe to tell someone who tests positive in the above population that they are indeed infected? Justify your response. [2]
ANS: [No,] [since they have only ~72% of actually being a true positive, i.e., PVP = .716].
(25) Do you think it would be safe to tell someone who tests negative in the above population that they are free from infection? Justify. [2]
ANS: [Yes,] since there is an almost 99.8% chance of being correct, i.e., [PVP = .998].
(26) What does "ICD" stand for? [3]
ANS [International] [Classification] of [Disease]