NR 503 Epidemiology midterm
questions & answers :
1. 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 prevalence rate of active influenza as of April 1, 2005, was:
Correct! 20 per 1,000 population
2. 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:
Correct! 20 per 1,000 population
3. 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?
Correct!: Rates would increase in women older than 50 years of age but may decrease in
younger women as they get older.
4. The ability of a single person to remain free of clinical illness following exposure to an infectious
agent is known as:
Correct!: Immunity
5. Which of the food items (or combination of items) is most likely to be the infective item(s)?
Correct!: Ice cream only
6. The case-fatality rate associated with plague is lowest in which community?
Correct Answer: Community C
7. The incidence and prevalence rates of a chronic childhood illness for a specific community are
given below.
Correct Answer: The duration of disease is becoming longer.
, 8. The following table gives the mean annual age-specific mortality rates from measles during the
first 25 years of life in successive 5-year periods. You may assume that the population is in a
steady state (i.e., migrations out are equal to migrations in). Based on the information above,
one may conclude:
Correct Answer: Children ages 5 to 9 had the highest rate of death in all periods
9. In 2001, a state enacted a law that required the use of safety seats for all children under 7 years
of age and mandatory seatbelt use for all persons. The table above lists the number of deaths
due to motor vehicle accidents (MVAs) and the total population by age in 2000 (before the law)
and in 2005 (4 years after the law was enacted).
Correct Answer: Correct, because both the total and the age-adjusted mortality rates are
higher in 2005 than in 2000
10. Which of the following is an advantage of active surveillance?
Correct!: More accurate due to reduced reporting burden for health care providers
11. A disease has an incidence of 10 per 1,000 persons per year, and 80% of those affected will die
within 1 year. Prior to the year 2000, only 50% of cases of the disease were detected by
physician diagnosis prior to death. In the year 2000, a lab test was developed that identified 90%
of cases an average of 6 months prior to symptom onset; however, the prognosis did not
improve after diagnosis. Which statement is true concerning the duration of the disease after
the development of the lab test?
Correct Answer: Mean duration of a case of the disease is longer in 2000
12. What is the overall attack rate in persons who did not eat ice cream? Correct!: 33%
13. The table above describes the number of illnesses and deaths caused by plague in four
communities. The proportionate mortality ratio associated with plague is lowest in which
community?
Correct!: Community D
14. Which of the following is characteristic of a single-exposure, common-vehicle outbreak?
Correct!: The epidemic curve has a normal distribution when plotted against the logarithm of time
15. The following table gives the mean annual age-specific mortality rates from measles during the
first 25 years of life in successive 5-year periods. You may assume that the population is in a
steady state (i.e., migrations out are equal to migrations in).
Correct Answer: 2.4 3.3 2.0 0.6 0.1
questions & answers :
1. 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 prevalence rate of active influenza as of April 1, 2005, was:
Correct! 20 per 1,000 population
2. 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:
Correct! 20 per 1,000 population
3. 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?
Correct!: Rates would increase in women older than 50 years of age but may decrease in
younger women as they get older.
4. The ability of a single person to remain free of clinical illness following exposure to an infectious
agent is known as:
Correct!: Immunity
5. Which of the food items (or combination of items) is most likely to be the infective item(s)?
Correct!: Ice cream only
6. The case-fatality rate associated with plague is lowest in which community?
Correct Answer: Community C
7. The incidence and prevalence rates of a chronic childhood illness for a specific community are
given below.
Correct Answer: The duration of disease is becoming longer.
, 8. The following table gives the mean annual age-specific mortality rates from measles during the
first 25 years of life in successive 5-year periods. You may assume that the population is in a
steady state (i.e., migrations out are equal to migrations in). Based on the information above,
one may conclude:
Correct Answer: Children ages 5 to 9 had the highest rate of death in all periods
9. In 2001, a state enacted a law that required the use of safety seats for all children under 7 years
of age and mandatory seatbelt use for all persons. The table above lists the number of deaths
due to motor vehicle accidents (MVAs) and the total population by age in 2000 (before the law)
and in 2005 (4 years after the law was enacted).
Correct Answer: Correct, because both the total and the age-adjusted mortality rates are
higher in 2005 than in 2000
10. Which of the following is an advantage of active surveillance?
Correct!: More accurate due to reduced reporting burden for health care providers
11. A disease has an incidence of 10 per 1,000 persons per year, and 80% of those affected will die
within 1 year. Prior to the year 2000, only 50% of cases of the disease were detected by
physician diagnosis prior to death. In the year 2000, a lab test was developed that identified 90%
of cases an average of 6 months prior to symptom onset; however, the prognosis did not
improve after diagnosis. Which statement is true concerning the duration of the disease after
the development of the lab test?
Correct Answer: Mean duration of a case of the disease is longer in 2000
12. What is the overall attack rate in persons who did not eat ice cream? Correct!: 33%
13. The table above describes the number of illnesses and deaths caused by plague in four
communities. The proportionate mortality ratio associated with plague is lowest in which
community?
Correct!: Community D
14. Which of the following is characteristic of a single-exposure, common-vehicle outbreak?
Correct!: The epidemic curve has a normal distribution when plotted against the logarithm of time
15. The following table gives the mean annual age-specific mortality rates from measles during the
first 25 years of life in successive 5-year periods. You may assume that the population is in a
steady state (i.e., migrations out are equal to migrations in).
Correct Answer: 2.4 3.3 2.0 0.6 0.1
