NR 503 MIDTERM EXAM
, NR 503 MIDTERM EXAM
Question 1
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
Explanation:
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 2
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
Explanation:
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 3
The population of a city on February 15, 2005, was 36,600. The city has a passive surveillance
system that collects hospital and private physician reports of influenza cases every month.
During the period between January 1 and April 1, 2005, 2,200 new cases of influenza occurred in
the city. Of these cases, 775 persons were ill with influenza according to surveillance reports on
April 1, 2005. The monthly incidence rate of active cases of influenza for the 3-month period
was:
4 per 1,000 population
17 per 1,000 population
20 per 1,000 population
, 39 per 1,000 population
130 per 1,000 population
Explanation:
The monthly incidence rate is calculated based on the number of new cases of a disease
developing during the 3-month time period. In this example, 2,200 cases of influenza developed
among an average population of 36,600 persons at risk during the surveillance period. The
incidence rate equals 2,200 divided by 36,600. In order to calculate the average monthly rate, the
rate should then be divided by 3. Finally, the monthly rate can be multiplied by 1,000 in order to
express it per the responses listed.
Question 4
What would be the effect on age-specific incidence rates of uterine cancer if women with
hysterectomies were excluded from the denominator of incidence calculations assuming that
most women who have had hysterectomies are older than 50 years of age.
The rates in all age groups would remain the same.
Only rates in women older than 50 years of age would tend to decrease.
Rates in women younger than 50 years would increase compared to women older than 50 years
of age.
Rates would increase in women older than 50 years of age but may decrease in younger
women as they get older.
, NR 503 MIDTERM EXAM
Question 1
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
Explanation:
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 2
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
Explanation:
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 3
The population of a city on February 15, 2005, was 36,600. The city has a passive surveillance
system that collects hospital and private physician reports of influenza cases every month.
During the period between January 1 and April 1, 2005, 2,200 new cases of influenza occurred in
the city. Of these cases, 775 persons were ill with influenza according to surveillance reports on
April 1, 2005. The monthly incidence rate of active cases of influenza for the 3-month period
was:
4 per 1,000 population
17 per 1,000 population
20 per 1,000 population
, 39 per 1,000 population
130 per 1,000 population
Explanation:
The monthly incidence rate is calculated based on the number of new cases of a disease
developing during the 3-month time period. In this example, 2,200 cases of influenza developed
among an average population of 36,600 persons at risk during the surveillance period. The
incidence rate equals 2,200 divided by 36,600. In order to calculate the average monthly rate, the
rate should then be divided by 3. Finally, the monthly rate can be multiplied by 1,000 in order to
express it per the responses listed.
Question 4
What would be the effect on age-specific incidence rates of uterine cancer if women with
hysterectomies were excluded from the denominator of incidence calculations assuming that
most women who have had hysterectomies are older than 50 years of age.
The rates in all age groups would remain the same.
Only rates in women older than 50 years of age would tend to decrease.
Rates in women younger than 50 years would increase compared to women older than 50 years
of age.
Rates would increase in women older than 50 years of age but may decrease in younger
women as they get older.
