Chapter 26: Epidemiology: Tracking Infectious Diseases
MULTIPLE CHOICE
1. Charlotte touches a doorknob after an individual with MRSA touched the doorknob. Immediately after
touching the knob, Charlotte scratches her leg and transmits some MRSA cells into a small wound.
The doorknob is functioning as a(n)
a. etiologic agent. c. mode of transmission.
b. reservoir. d. host.
ANS: C DIF: Moderate REF: 26.1
OBJ: 26.1a Explain the four major links in a chain of infection.
MSC: Applying
2. A man infected with a viral respiratory infection sneezes and releases tiny droplets containing viral
particles. Two minutes later, a woman breathes in some of these tiny droplets and becomes infected by
the same viral infection. The movement of this virus from one individual to another is best described
as the
a. etiologic agent. c. mode of transmission.
b. reservoir. d. host.
ANS: C DIF: Easy REF: 26.1
OBJ: 26.1a Explain the four major links in a chain of infection.
MSC: Understanding
3. Psittacosis is a zoonotic disease contracted by humans during contact with bacteria found in bird
droppings. Human-to-human transmission is rare. Reducing contact with bird droppings will break the
chain of infection by
a. reducing the virulence of the bacteria responsible for causing the disease.
b. affecting the bacteria’s portal of entry into the human body.
c. reducing the number of organisms acting as reservoirs for the bacteria.
d. reducing the transmission of bacteria from the reservoir to humans.
ANS: D DIF: Moderate REF: 26.1
OBJ: 26.1a Explain the four major links in a chain of infection.
MSC: Applying
4. Which of the following does NOT involve testing a hypothesis?
a. descriptive epidemiology c. experimental study
b. analytical epidemiology d. cohort study
ANS: A DIF: Easy REF: 26.1
OBJ: 26.1b Differentiate between descriptive and analytical epidemiology.
MSC: Understanding
5. An investigator is collecting data identifying the time of year and locations of measles outbreaks
within the United States over a ten-year period from 2000 to 2010. This investigator is most likely
involved in
, a. descriptive epidemiology. c. analytical epidemiology.
b. cohort studies. d. experimental studies.
ANS: A DIF: Moderate REF: 26.1
OBJ: 26.1b Differentiate between descriptive and analytical epidemiology.
MSC: Understanding
6. Although sporadic outbreaks of measles occur in the United States, the disease is considered
nonendemic. What differentiates measles from endemic diseases, such as chickenpox?
a. Endemic diseases exhibit higher numbers of cases than a sporadic outbreak.
b. Diseases that are not endemic lack a reservoir in the area.
c. Endemic diseases do not exhibit sporadic outbreaks.
d. Diseases that are not endemic remain in reservoirs without infecting humans.
ANS: B DIF: Easy REF: 26.1
OBJ: 26.1c Define “endemic,” “epidemic,” and “pandemic,” and explain the difference between
disease prevalence and incidence. MSC: Understanding
7. This map shows the incidence of syphilis in the United States in 2012. Based on the map shown,
which of the following statements is true?
a. Efforts to prevent syphilis in the southern states failed to prevent an increase in the number
of new cases in 2012.
b. No individuals in Montana were infected with syphilis in 2012.
c. The number of new cases of syphilis was higher in Texas than it was in North Dakota in
2012.
d. The total number of active cases of syphilis in 2012 was highest in the southern states.
ANS: C DIF: Difficult REF: 26.1
OBJ: 26.1c Define “endemic,” “epidemic,” and “pandemic,” and explain the difference between
disease prevalence and incidence. MSC: Evaluating
8. This map shows the incidence of Lyme disease in the United States in 2012. Based on the map shown,
which of the following statements is true?
, a. Lyme disease exhibits geographical clusters in the Northeast.
b. A decrease in Lyme disease vaccinations led to an increase in Lyme disease incidence in
2012.
c. Lyme disease is maintained in a reservoir that is restricted to the Northeast.
d. The number of Lyme disease cases has been steadily increasing since the 1970s.
ANS: A DIF: Moderate REF: 26.1
OBJ: 26.1c Define “endemic,” “epidemic,” and “pandemic,” and explain the difference between
disease prevalence and incidence. MSC: Applying
9. Which of the following statements is a description of the prevalence of chlamydia?
a. There are 57 active cases of chlamydia on a university campus.
b. There were 57 new cases of chlamydia on a university campus last week.
c. There were 123 new cases of chlamydia on a university campus last year.
d. Young women on a university campus are twice as likely as young men to develop
chlamydia.
ANS: A DIF: Moderate REF: 26.1
OBJ: 26.1c Define “endemic,” “epidemic,” and “pandemic,” and explain the difference between
disease prevalence and incidence. MSC: Applying
10. Which of the following would indicate efforts to control a disease are working?
a. The disease becomes endemic.
b. The disease prevalence increases.
c. The disease incidence decreases.
d. Outbreaks of the disease only occur every other year.
ANS: C DIF: Easy REF: 26.1
OBJ: 26.1c Define “endemic,” “epidemic,” and “pandemic,” and explain the difference between
disease prevalence and incidence. MSC: Understanding
11. In the figure shown, the lower part of the line on the graph represents a low, steady number of disease
cases, which is indicative of a(n)
MULTIPLE CHOICE
1. Charlotte touches a doorknob after an individual with MRSA touched the doorknob. Immediately after
touching the knob, Charlotte scratches her leg and transmits some MRSA cells into a small wound.
The doorknob is functioning as a(n)
a. etiologic agent. c. mode of transmission.
b. reservoir. d. host.
ANS: C DIF: Moderate REF: 26.1
OBJ: 26.1a Explain the four major links in a chain of infection.
MSC: Applying
2. A man infected with a viral respiratory infection sneezes and releases tiny droplets containing viral
particles. Two minutes later, a woman breathes in some of these tiny droplets and becomes infected by
the same viral infection. The movement of this virus from one individual to another is best described
as the
a. etiologic agent. c. mode of transmission.
b. reservoir. d. host.
ANS: C DIF: Easy REF: 26.1
OBJ: 26.1a Explain the four major links in a chain of infection.
MSC: Understanding
3. Psittacosis is a zoonotic disease contracted by humans during contact with bacteria found in bird
droppings. Human-to-human transmission is rare. Reducing contact with bird droppings will break the
chain of infection by
a. reducing the virulence of the bacteria responsible for causing the disease.
b. affecting the bacteria’s portal of entry into the human body.
c. reducing the number of organisms acting as reservoirs for the bacteria.
d. reducing the transmission of bacteria from the reservoir to humans.
ANS: D DIF: Moderate REF: 26.1
OBJ: 26.1a Explain the four major links in a chain of infection.
MSC: Applying
4. Which of the following does NOT involve testing a hypothesis?
a. descriptive epidemiology c. experimental study
b. analytical epidemiology d. cohort study
ANS: A DIF: Easy REF: 26.1
OBJ: 26.1b Differentiate between descriptive and analytical epidemiology.
MSC: Understanding
5. An investigator is collecting data identifying the time of year and locations of measles outbreaks
within the United States over a ten-year period from 2000 to 2010. This investigator is most likely
involved in
, a. descriptive epidemiology. c. analytical epidemiology.
b. cohort studies. d. experimental studies.
ANS: A DIF: Moderate REF: 26.1
OBJ: 26.1b Differentiate between descriptive and analytical epidemiology.
MSC: Understanding
6. Although sporadic outbreaks of measles occur in the United States, the disease is considered
nonendemic. What differentiates measles from endemic diseases, such as chickenpox?
a. Endemic diseases exhibit higher numbers of cases than a sporadic outbreak.
b. Diseases that are not endemic lack a reservoir in the area.
c. Endemic diseases do not exhibit sporadic outbreaks.
d. Diseases that are not endemic remain in reservoirs without infecting humans.
ANS: B DIF: Easy REF: 26.1
OBJ: 26.1c Define “endemic,” “epidemic,” and “pandemic,” and explain the difference between
disease prevalence and incidence. MSC: Understanding
7. This map shows the incidence of syphilis in the United States in 2012. Based on the map shown,
which of the following statements is true?
a. Efforts to prevent syphilis in the southern states failed to prevent an increase in the number
of new cases in 2012.
b. No individuals in Montana were infected with syphilis in 2012.
c. The number of new cases of syphilis was higher in Texas than it was in North Dakota in
2012.
d. The total number of active cases of syphilis in 2012 was highest in the southern states.
ANS: C DIF: Difficult REF: 26.1
OBJ: 26.1c Define “endemic,” “epidemic,” and “pandemic,” and explain the difference between
disease prevalence and incidence. MSC: Evaluating
8. This map shows the incidence of Lyme disease in the United States in 2012. Based on the map shown,
which of the following statements is true?
, a. Lyme disease exhibits geographical clusters in the Northeast.
b. A decrease in Lyme disease vaccinations led to an increase in Lyme disease incidence in
2012.
c. Lyme disease is maintained in a reservoir that is restricted to the Northeast.
d. The number of Lyme disease cases has been steadily increasing since the 1970s.
ANS: A DIF: Moderate REF: 26.1
OBJ: 26.1c Define “endemic,” “epidemic,” and “pandemic,” and explain the difference between
disease prevalence and incidence. MSC: Applying
9. Which of the following statements is a description of the prevalence of chlamydia?
a. There are 57 active cases of chlamydia on a university campus.
b. There were 57 new cases of chlamydia on a university campus last week.
c. There were 123 new cases of chlamydia on a university campus last year.
d. Young women on a university campus are twice as likely as young men to develop
chlamydia.
ANS: A DIF: Moderate REF: 26.1
OBJ: 26.1c Define “endemic,” “epidemic,” and “pandemic,” and explain the difference between
disease prevalence and incidence. MSC: Applying
10. Which of the following would indicate efforts to control a disease are working?
a. The disease becomes endemic.
b. The disease prevalence increases.
c. The disease incidence decreases.
d. Outbreaks of the disease only occur every other year.
ANS: C DIF: Easy REF: 26.1
OBJ: 26.1c Define “endemic,” “epidemic,” and “pandemic,” and explain the difference between
disease prevalence and incidence. MSC: Understanding
11. In the figure shown, the lower part of the line on the graph represents a low, steady number of disease
cases, which is indicative of a(n)
