NR 503 Final exam Question And Answers
NR 503 Final exam Question And Answers
1. Which of the following reasons can explain why a person who did not consume
the infective food item got sick?
a. They were directly exposed to persons who did eat the infective food
item
b. Diarrhea is a general symptom consistent with a number of illnesses
c. There may have been an inaccurate recall of which foods were eaten
d. All of the above
e. None of the above
Rationale: Without knowledge as to the specific agent in this instance, it is also likely that
it can be spread by direct contact with infected persons. Since diarrhea is a general
disease symptom, it is possible that several infectious agents may be present at this meal
or others eaten during the same time period. Further, information regarding food
consumption may have been collected long after the disease episode. This may have led
persons to incorrectly remember the foods that they consumed.
An outbreak of gastroenteritis occurred at a boarding school with a student enrollment of
846. Fifty-seven students reported symptoms including vomiting, diarrhea, nausea, & low-
grade fever between 10 p.m. on September 24 & 8 p.m. on September 25. The ill students
lived in dormitories that housed 723 of the students. The table below provides
information on the number of students per type of residence & the number reporting
illnesses consistent with the described symptoms & onset time. Calculate the attack rate
among all students at the boarding school.
1. Calculate the attack rate among all students at the boarding school.
57/846 = The answer is found by dividing the total number of cases (57) by the total
number of students (846). This equals 6.7%.
10. Calculate the attack rates for boys & girls separately.
a. For boys, the attack rate includes all cases (40 + 3) divided by the total number of
students who are boys (380 + 46). The attack rate is 10.1%.
, NR 503 Final exam Question And Answers
b. For girls, the attack rate includes all cases (12 + 2) divided by the total number of
students who are girls (343 + 77). The attack rate is 3.3%.
Chapters 2-4
2. Which of the following is a condition which may occur during the incubation period?
a. Onset of clinical illness
b. Receipt of infection
c. Signs & symptoms of disease
d. Transmission of infection
e. Isolation of disease carrier through quarantine
Rationale: The incubation period is defined as the interval from receipt of infection to the time of
onset of clinical illness. Accordingly, individuals may transmit infectious agents during the
incubation period as they show no signs of disease that would enable the isolation of sick
individuals by quarantine.
3. Chicken pox is a highly communicable disease. It may be transmitted by direct contact with a person
infected with the varicella-zoster virus (VZV). The typical incubation time is between 10 to 20 days. A
boy started school 2 weeks after showing symptoms of chicken pox including mild fever, skin rash, &
fluid-filled blisters. One month after the boy returned to school, none of his classmates had been
infected by VZV. The main reason was:
a. Herd immunity
b. All had been immunized prior to the school year
c. Contact was after infectious period
d. Subclinical infections were not yet detected
e. Disease was endemic in the class
Rationale: The disease is spread by contact with an infected individual who can transmit the agent
(VZV) to immunologically naive persons during the incubation period & for several days after onset
of clinical illness. Since the boy started school 14 days after showing signs consistent with chicken
pox, it is most likely that he was no longer infectious.
4. Which of the following is characteristic of a single-exposure, common-vehicle outbreak?
a. Long latency period before many illnesses develop
b. There is an exponential increase in secondary cases following initial exposures
c. Cases include only those who have been exposed to sick persons
d. The epidemic curve has a normal distribution when plotted against the logarithm of
time
e. Wide range in incubation times for sick individuals
NR 503 Final exam Question And Answers
1. Which of the following reasons can explain why a person who did not consume
the infective food item got sick?
a. They were directly exposed to persons who did eat the infective food
item
b. Diarrhea is a general symptom consistent with a number of illnesses
c. There may have been an inaccurate recall of which foods were eaten
d. All of the above
e. None of the above
Rationale: Without knowledge as to the specific agent in this instance, it is also likely that
it can be spread by direct contact with infected persons. Since diarrhea is a general
disease symptom, it is possible that several infectious agents may be present at this meal
or others eaten during the same time period. Further, information regarding food
consumption may have been collected long after the disease episode. This may have led
persons to incorrectly remember the foods that they consumed.
An outbreak of gastroenteritis occurred at a boarding school with a student enrollment of
846. Fifty-seven students reported symptoms including vomiting, diarrhea, nausea, & low-
grade fever between 10 p.m. on September 24 & 8 p.m. on September 25. The ill students
lived in dormitories that housed 723 of the students. The table below provides
information on the number of students per type of residence & the number reporting
illnesses consistent with the described symptoms & onset time. Calculate the attack rate
among all students at the boarding school.
1. Calculate the attack rate among all students at the boarding school.
57/846 = The answer is found by dividing the total number of cases (57) by the total
number of students (846). This equals 6.7%.
10. Calculate the attack rates for boys & girls separately.
a. For boys, the attack rate includes all cases (40 + 3) divided by the total number of
students who are boys (380 + 46). The attack rate is 10.1%.
, NR 503 Final exam Question And Answers
b. For girls, the attack rate includes all cases (12 + 2) divided by the total number of
students who are girls (343 + 77). The attack rate is 3.3%.
Chapters 2-4
2. Which of the following is a condition which may occur during the incubation period?
a. Onset of clinical illness
b. Receipt of infection
c. Signs & symptoms of disease
d. Transmission of infection
e. Isolation of disease carrier through quarantine
Rationale: The incubation period is defined as the interval from receipt of infection to the time of
onset of clinical illness. Accordingly, individuals may transmit infectious agents during the
incubation period as they show no signs of disease that would enable the isolation of sick
individuals by quarantine.
3. Chicken pox is a highly communicable disease. It may be transmitted by direct contact with a person
infected with the varicella-zoster virus (VZV). The typical incubation time is between 10 to 20 days. A
boy started school 2 weeks after showing symptoms of chicken pox including mild fever, skin rash, &
fluid-filled blisters. One month after the boy returned to school, none of his classmates had been
infected by VZV. The main reason was:
a. Herd immunity
b. All had been immunized prior to the school year
c. Contact was after infectious period
d. Subclinical infections were not yet detected
e. Disease was endemic in the class
Rationale: The disease is spread by contact with an infected individual who can transmit the agent
(VZV) to immunologically naive persons during the incubation period & for several days after onset
of clinical illness. Since the boy started school 14 days after showing signs consistent with chicken
pox, it is most likely that he was no longer infectious.
4. Which of the following is characteristic of a single-exposure, common-vehicle outbreak?
a. Long latency period before many illnesses develop
b. There is an exponential increase in secondary cases following initial exposures
c. Cases include only those who have been exposed to sick persons
d. The epidemic curve has a normal distribution when plotted against the logarithm of
time
e. Wide range in incubation times for sick individuals
