NR 503 Week 8 Final Exam: Student Consult Questions with Rationale. Latest 2021. Graded A.Question 1
Which of the following is a condition which may
... [Show More] occur during the incubation period?
Onset of clinical illness
Receipt of infection
Signs and symptoms of disease
Transmission of infection
Isolation of disease carrier through quarantine
That's correct!
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.
Question 2
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, and fluid-filled blisters. One month after the
boy returned to school, none of his classmates had been infected by VZV. The main
reason was:
Herd immunity
All had been immunized prior to the school year
Contact was after infectious period
Subclinical infections were not yet detected
Disease was endemic in the class
That's correct!
The disease is spread by contact with an infected individual who can transmit
the agent (VZV) to immunologically naive persons during the incubation period
and 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.
Question 3
The ability of a single person to remain free of clinical illness following exposure to an
infectious agent is known as:
Hygiene
Vaccination
Herd immunity
Immunity
Latency
That's correct!
Immunity is the capacity of a single individual to avoid disease susceptibility
when exposed to an infectious agent. Herd immunity is a population
characteristic. For certain diseases, individual immunity can be acquired by
vaccination, but this is not true for all infectious diseases.
Question 4
Which of the following is characteristic of a single-exposure, common-vehicle outbreak?
Long latency period before many illnesses develop
There is an exponential increase in secondary cases following initial exposures
Cases include only those who have been exposed to sick persons
The epidemic curve has a normal distribution when plotted against the logarithm
of time
Wide range in incubation times for sick individuals
That's correct!
Single-exposure, common-vehicle outbreaks involve a sudden, rapid increase in
cases of disease that are limited to persons who share a common exposure.
Additionally, few secondary cases develop among persons exposed to primary
cases. A histogram of the outbreak can plot the number of cases by time of
disease onset. In single-exposure, common-vehicle outbreaks, a log
transformation of the time of disease onset will often take on the characteristic
shape of a normal distribution (i.e., a bell curve) with the median incubation
time found at the peak of the curve.
Question 5
What is the diarrhea attack rate in persons who ate both ice cream and pizza?
39/52
21/70
39/67
51/67
none of the above
That's correct!
The attack rate in this example is defined as the number of persons who
develop diarrhea divided by the total number of people at risk. In this example,
the at-risk group is those who have eaten both ice cream and pizza. Of these 52
persons, 39 developed diarrhea.
Question 6
What is the overall attack rate in persons who did not eat ice cream?
30%
33%
35%
44%
58%
That's correct!
The attack rate is the number of persons with diarrhea (14 + 9) divided by the
total number of persons who did not eat ice cream (40 + 30).
Question 7
Which of the food items (or combination of items) is most likely to be the infective
item(s)?
Pizza only
Ice cream only
Neither pizza nor ice cream
Both pizza and ice cream
Cannot be assumed from the data shown
That's correct!
Among persons eating ice cream, over 70% developed diarrhea regardless of
their pizza consumption (39/52 and 11/15). Among both groups of persons who
did not eat ice cream, each attack rate was equal to or less than 35% (14/40
and 9/30).
Question 8
Which of the following reasons can explain why a person who did not consume the
infective food item got sick?
They were directly exposed to persons who did eat the infective food item
Diarrhea is a general symptom consistent with a number of illnesses
There may have been an inaccurate recall of which foods were eaten
All of the above
None of the above
That's correct!
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.
Question 9
An outbreak of gastroenteritis occurred at a boarding school with a student enrollment
of 846. Fifty-seven students reported symptoms including vomiting, diarrhea, nausea,
and low-grade fever between 10 p.m. on September 24 and 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 and the number
reporting illnesses consistent with the described symptoms and onset time. Calculate
the attack rate among all students at the boarding school.
That's correct!
The answer is found by dividing the total number of cases (57) by the total
number of students (846). This equals 6.7%.
6.7
Question 10
An outbreak of gastroenteritis occurred at a boarding school with a student enrollment
of 846. Fifty-seven students reported symptoms including vomiting, diarrhea, nausea,
and low-grade fever between 10 p.m. on September 24 and 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 and the number
reporting illnesses consistent with the described symptoms and onset time. Calculate
the attack rates for boys and girls separately.
That's correct!
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%.
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%. [Show Less]