NR 503 FINAL EXAM QUESTION AND
ANSWERS
(COMPLETE SOLUTIONS AND RESOURCES FOR
THE COURSE EXAM)
Chapters 2-4 sd
1. Which of the following is a condition which may occur during the incubation per
sd sd sd sd sd sd sd sd sd sd sd sd sd
iod?
a. Onset of clinical illness sd sd sd
b. Receipt of infection s d s d
c. Signs & symptoms of disease sd sd sd sd
d. Transmission of infection sd sd
e. Isolation of disease carrier through quarantine sd sd sd sd sd
Rationale: The incubation period is defined as the interval from receipt of infectio
s d sd sd sd sd sd sd sd sd sd sd sd
n to the time of onset of clinical illness. Accordingly, individuals may transmit infect
sd sd sd sd sd sd sd sd sd sd sd sd sd
ious agents during the incubation period as they show no signs of disease that would
sd sd sd sd sd sd sd sd sd sd sd sd sd sd sd
enable the isolation of sick individuals by quarantine.
sd sd sd sd sd sd sd
2. Chicken pox is a highly communicable disease. It may be transmitted by direct conta
sd sd sd sd sd sd sd sd sd sd sd sd sd
ct with a person infected with the varicella-
sd sd sd sd sd sd sd
zoster virus (VZV). The typical incubation time is between 10 to 20 days. A boy starte
sd sd sd sd sd sd sd sd sd sd sd sd sd sd sd
d school 2 weeks after showing symptoms of chicken pox including mild fever, skin ra
sd sd sd sd sd sd sd sd sd sd sd sd sd sd
sh, & fluid- sd sd
filled blisters. One month after the boy returned to school, none of his classmates ha
sd sd sd sd sd sd sd sd sd sd sd sd sd sd
d been infected by VZV. The main reason was:
sd sd sd sd sd sd sd sd
a. Herd immunity sd
b. All had been immunized prior to the school year sd sd sd sd sd sd sd sd
c. Contact was after infectious period sd sd sd sd
d. Subclinical infections were not yet detected sd sd sd sd sd
e. Disease was endemic in the class sd sd sd sd sd
Rationale: The disease is spread by contact with an infected individual who can tran
sd sd sd sd sd sd sd sd sd sd sd sd sd
smit the agent (VZV) to immunologically naive persons during the incubation p
s d s d s d s d s d s d s d s d s d sd sd
eriod & for several days after onset of clinical illness. Since the boy started school 1
sd sd sd sd sd sd sd sd sd sd sd sd sd s d s d
4 days after showing signs consistent with chicken pox, it is most likely that he w
s d s d s d s d s d s d s d s d s d s d sd sd sd sd sd
as no longer infectious.
sd sd sd
3. Which of the following is characteristic of a single-exposure, common-
sd sd sd sd sd sd sd sd sd
vehicle outbreak? sd
,a. Long latency period before many illnesses develop
sd sd sd sd sd sd
, b. There is an exponential increase in secondary cases following initial exposures
sd sd sd sd sd sd sd sd sd sd
c. Cases include only those who have been exposed to sick persons
sd sd sd sd sd sd sd sd sd sd
d. The epidemic curve has a normal distribution when plotted against the logarithm of ti
sd sd sd sd sd sd sd sd sd sd sd sd sd
me
e. Wide range in incubation times for sick individualssd sd sd sd sd sd sd
Rationale: Single-exposure, common- sd sd
vehicle outbreaks involve a sudden, rapid increase in cases of disease that are limit
sd sd sd sd sd s d sd sd sd sd sd sd sd
ed to persons who share a common exposure. Additionally, few secondary cases dev
sd sd sd sd sd sd sd sd sd sd sd sd
elop among persons exposed to primary cases. A histogram of the outbreak can pl
sd sd sd sd sd s d s d s d s d s d s d s d s d
ot the number of cases by time of disease onset. In single-exposure, common-
s d s d s d s d s d sd sd sd sd sd sd sd
vehicle outbreaks, a log transformation of the time of disease onset will often take o
sd sd sd sd sd sd sd sd sd sd sd sd sd sd
n the characteristic shape of a normal distribution (i.e., a bell curve) with the media
sd sd sd sd sd sd sd sd sd sd sd sd sd sd
n incubation time found at the peak of the curve.
sd sd sd sd sd sd sd sd sd
4. What is the diarrhea attack rate in persons who ate both ice cream & pizza?
sd sd sd sd sd sd sd sd sd sd sd sd sd sd
a. 39/52
b. 21/70
c. 39/67
d. 51/67
e. None of the above sd sd sd
Rationale:
The attack rate in this example is defined as the number of persons who develop dia
sd sd sd sd sd sd sd sd sd sd sd sd sd sd sd
rrhea divided by the total number of people at risk. In this example, the at-
sd sd sd sd sd sd sd sd sd sd sd sd sd sd
risk group is those who have eaten both ice cream & pizza. Of these 52 persons, 39 d
sd sd sd sd sd sd sd sd sd sd sd sd sd sd sd sd sd
eveloped diarrhea. sd
5. What is the overall attack rate in persons who did not eat ice cream?
sd sd sd sd sd sd sd sd sd sd sd sd sd
a. 30%
b. 33%
c. 35%
d. 44%
e. 58%
Rationale:
The attack rate isthenumber of persons withdiarrhea (14 +9) divided by the total nu
sd sd sd sd sd sd sd sd sd sd sd s
d sd sd sd sd sd
mber of persons who did not eat ice cream (40 + 30).
sd sd sd sd sd sd sd sd sd sd sd
ANSWERS
(COMPLETE SOLUTIONS AND RESOURCES FOR
THE COURSE EXAM)
Chapters 2-4 sd
1. Which of the following is a condition which may occur during the incubation per
sd sd sd sd sd sd sd sd sd sd sd sd sd
iod?
a. Onset of clinical illness sd sd sd
b. Receipt of infection s d s d
c. Signs & symptoms of disease sd sd sd sd
d. Transmission of infection sd sd
e. Isolation of disease carrier through quarantine sd sd sd sd sd
Rationale: The incubation period is defined as the interval from receipt of infectio
s d sd sd sd sd sd sd sd sd sd sd sd
n to the time of onset of clinical illness. Accordingly, individuals may transmit infect
sd sd sd sd sd sd sd sd sd sd sd sd sd
ious agents during the incubation period as they show no signs of disease that would
sd sd sd sd sd sd sd sd sd sd sd sd sd sd sd
enable the isolation of sick individuals by quarantine.
sd sd sd sd sd sd sd
2. Chicken pox is a highly communicable disease. It may be transmitted by direct conta
sd sd sd sd sd sd sd sd sd sd sd sd sd
ct with a person infected with the varicella-
sd sd sd sd sd sd sd
zoster virus (VZV). The typical incubation time is between 10 to 20 days. A boy starte
sd sd sd sd sd sd sd sd sd sd sd sd sd sd sd
d school 2 weeks after showing symptoms of chicken pox including mild fever, skin ra
sd sd sd sd sd sd sd sd sd sd sd sd sd sd
sh, & fluid- sd sd
filled blisters. One month after the boy returned to school, none of his classmates ha
sd sd sd sd sd sd sd sd sd sd sd sd sd sd
d been infected by VZV. The main reason was:
sd sd sd sd sd sd sd sd
a. Herd immunity sd
b. All had been immunized prior to the school year sd sd sd sd sd sd sd sd
c. Contact was after infectious period sd sd sd sd
d. Subclinical infections were not yet detected sd sd sd sd sd
e. Disease was endemic in the class sd sd sd sd sd
Rationale: The disease is spread by contact with an infected individual who can tran
sd sd sd sd sd sd sd sd sd sd sd sd sd
smit the agent (VZV) to immunologically naive persons during the incubation p
s d s d s d s d s d s d s d s d s d sd sd
eriod & for several days after onset of clinical illness. Since the boy started school 1
sd sd sd sd sd sd sd sd sd sd sd sd sd s d s d
4 days after showing signs consistent with chicken pox, it is most likely that he w
s d s d s d s d s d s d s d s d s d s d sd sd sd sd sd
as no longer infectious.
sd sd sd
3. Which of the following is characteristic of a single-exposure, common-
sd sd sd sd sd sd sd sd sd
vehicle outbreak? sd
,a. Long latency period before many illnesses develop
sd sd sd sd sd sd
, b. There is an exponential increase in secondary cases following initial exposures
sd sd sd sd sd sd sd sd sd sd
c. Cases include only those who have been exposed to sick persons
sd sd sd sd sd sd sd sd sd sd
d. The epidemic curve has a normal distribution when plotted against the logarithm of ti
sd sd sd sd sd sd sd sd sd sd sd sd sd
me
e. Wide range in incubation times for sick individualssd sd sd sd sd sd sd
Rationale: Single-exposure, common- sd sd
vehicle outbreaks involve a sudden, rapid increase in cases of disease that are limit
sd sd sd sd sd s d sd sd sd sd sd sd sd
ed to persons who share a common exposure. Additionally, few secondary cases dev
sd sd sd sd sd sd sd sd sd sd sd sd
elop among persons exposed to primary cases. A histogram of the outbreak can pl
sd sd sd sd sd s d s d s d s d s d s d s d s d
ot the number of cases by time of disease onset. In single-exposure, common-
s d s d s d s d s d sd sd sd sd sd sd sd
vehicle outbreaks, a log transformation of the time of disease onset will often take o
sd sd sd sd sd sd sd sd sd sd sd sd sd sd
n the characteristic shape of a normal distribution (i.e., a bell curve) with the media
sd sd sd sd sd sd sd sd sd sd sd sd sd sd
n incubation time found at the peak of the curve.
sd sd sd sd sd sd sd sd sd
4. What is the diarrhea attack rate in persons who ate both ice cream & pizza?
sd sd sd sd sd sd sd sd sd sd sd sd sd sd
a. 39/52
b. 21/70
c. 39/67
d. 51/67
e. None of the above sd sd sd
Rationale:
The attack rate in this example is defined as the number of persons who develop dia
sd sd sd sd sd sd sd sd sd sd sd sd sd sd sd
rrhea divided by the total number of people at risk. In this example, the at-
sd sd sd sd sd sd sd sd sd sd sd sd sd sd
risk group is those who have eaten both ice cream & pizza. Of these 52 persons, 39 d
sd sd sd sd sd sd sd sd sd sd sd sd sd sd sd sd sd
eveloped diarrhea. sd
5. What is the overall attack rate in persons who did not eat ice cream?
sd sd sd sd sd sd sd sd sd sd sd sd sd
a. 30%
b. 33%
c. 35%
d. 44%
e. 58%
Rationale:
The attack rate isthenumber of persons withdiarrhea (14 +9) divided by the total nu
sd sd sd sd sd sd sd sd sd sd sd s
d sd sd sd sd sd
mber of persons who did not eat ice cream (40 + 30).
sd sd sd sd sd sd sd sd sd sd sd
