NR 503 Epidemiology Midterm Questions & Answers
(Graded A)
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:
Answer: 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:
Answer: 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?
Answer: 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:
Answer: Immunity
5. Which of the following reasons can explain why a person who did not consume the
infective food item got sick?
Answer: All of the above
6. Which of the food items (or combination of items) is most likely to be the infective
item(s)?
Answer: Ice cream only
, 7. The case-fatality rate associated with plague is lowest in which community?
Answer: Community C
8. The incidence and prevalence rates of a chronic childhood illness for a specific
community are given below.
Answer: The duration of disease is becoming longer.
9. 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:
Answer: Children ages 5 to 9 had the highest rate of death in all periods
10. In a country with a population of 16 million people, 175,000 deaths occurred during the
year ending December 31, 2005. These included 45,000 deaths from tuberculosis (TB) in
135,000 persons who were sick with TB. Assume that the population remained constant
throughout the year. Not all 135,000 cases of TB were contracted during 2005. Which of
the following statements is true?
Answer: None of the above
11. 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).
Answer: Correct, because both the total and the age-adjusted mortality rates are
higher in 2005 than in 2000
12. Which of the following is an advantage of active surveillance?
Answer: More accurate due to reduced reporting burden for health care providers
13. 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?
Answer: Mean duration of a case of the disease is longer in 2000
(Graded A)
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:
Answer: 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:
Answer: 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?
Answer: 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:
Answer: Immunity
5. Which of the following reasons can explain why a person who did not consume the
infective food item got sick?
Answer: All of the above
6. Which of the food items (or combination of items) is most likely to be the infective
item(s)?
Answer: Ice cream only
, 7. The case-fatality rate associated with plague is lowest in which community?
Answer: Community C
8. The incidence and prevalence rates of a chronic childhood illness for a specific
community are given below.
Answer: The duration of disease is becoming longer.
9. 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:
Answer: Children ages 5 to 9 had the highest rate of death in all periods
10. In a country with a population of 16 million people, 175,000 deaths occurred during the
year ending December 31, 2005. These included 45,000 deaths from tuberculosis (TB) in
135,000 persons who were sick with TB. Assume that the population remained constant
throughout the year. Not all 135,000 cases of TB were contracted during 2005. Which of
the following statements is true?
Answer: None of the above
11. 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).
Answer: Correct, because both the total and the age-adjusted mortality rates are
higher in 2005 than in 2000
12. Which of the following is an advantage of active surveillance?
Answer: More accurate due to reduced reporting burden for health care providers
13. 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?
Answer: Mean duration of a case of the disease is longer in 2000
