, TABLE OF CONTENTS
Chapter 1: History and Scope of Epidemiology
Chapter 2: Practical Applications of Epidemiology
Chapter 3: Measures of Morbidity and Mortality Used in Epidemiology
Chapter 4: Descriptive Epidemiology: Person, Place, Time
Chapter 5: Sources of Data for Use in Epidemiology
Chapter 6: Measures of Effect
Chapter 7: Study Designs: Ecologic and Cross-Sectional
Chapter 8: Experimental Study Designs
Chapter 9: Confounding, Selection Bias, Information Bias: Threats to Internal Validity
Chapter 10: Study Designs: Cohort Studies
Chapter 11: Study Designs: Case-Control Studies
Chapter 12: Screening for Disease in the Community
Chapter 13: Epidemiology of Infectious Diseases
Chapter 14: Epidemiologic Aspects of Work and the Environment
Chapter 15: Molecular and Genetic Epidemiology
Chapter 16: Social, Behavioral, and Psychosocial Epidemiology
Chapter 17: Epidemiology as a Profession
Chapter 18: Epidemiology and Health Policy
,Chapter 1: History and Scope of Epidemiology
1. Which component of the formal definition of epidemiology refers to the systematic search for factors
or events capable of bringing about a change in health status?
A. Distribution
B. Surveillance
C. Determinants
D. Quantification
Answer: C
Rationale: In epidemiology, determinants encompass biological agents, chemical exposures,
socioeconomic factors, and lifestyle behaviors that directly influence or produce changes in health
status. Identifying determinants allows public health practitioners to design targeted interventions
aimed at primary prevention. Distribution, by contrast, describes the frequency and pattern of health
events by person, place, and time.
Keywords: Determinants, Definition of Epidemiology, Causation
2. A county health department notes that the baseline occurrence of Giardia infections in its jurisdiction
is approximately 4 cases per month. Over the past three weeks, 42 lab-confirmed cases have been
reported among residents who used a public municipal pool. This phenomenon is best classified as an:
A. Pandemic
, B. Epidemic
C. Hyperendemic equilibrium
D. Endemic baseline
Answer: B
Rationale: An epidemic is defined as the occurrence in a community or region of cases of an illness,
specific health-related behavior, or other health-related events clearly in excess of normal expectancy.
Because 42 cases over three weeks vastly exceeds the established background expectancy of 4 cases per
month, the event represents an epidemic (or localized outbreak). Endemicity refers strictly to the
habitual, ongoing presence of a disease within a given geographic area.
Keywords: Epidemic, Outbreak Investigation, Disease Frequency
3. Which of the following classical treatises marked a fundamental departure from supernatural
explanations of disease by proposing that environmental factors such as climate, water sources, and
geography influence illness?
A. Natural and Political Observations on the Bills of Mortality
B. Airs, Waters, and Places
C. De Contagione et Contagiosis Morbis
D. Micrographia
Answer: B
Rationale: Written by Hippocrates around 400 BCE, Airs, Waters, and Places established the
foundational epidemiologic observation that environmental conditions and human behaviors shape the
distribution of disease in populations. This work shifted medical thinking away from superstitious beliefs
toward empirical observation of nature and geography. John Graunt authored the Bills of Mortality
treatise two millennia later.
Keywords: Hippocrates, History of Epidemiology, Environmental Health
,4. John Graunt’s 1662 publication, *Natural and Political Observations Mentioned in a Following Index,
and Made upon the Bills of Mortality*, is considered foundational to modern epidemiology primarily
because it:
A. Established the first laboratory culture techniques for enteric bacteria
B. Identified the waterborne transmission mechanism of Vibrio cholerae
C. Formulated the modern four-phase framework for randomized clinical trials
D. Demonstrated the utility of quantitative vital statistics to identify population mortality patterns
Answer: D
Rationale: John Graunt was the first to systematically compile, quantify, and analyze weekly church
birth and death records (Bills of Mortality) in London, recording gender differences, infant mortality, and
seasonal variations. His pioneering work established demography and vital statistics as core quantitative
tools of epidemiology. John Snow later investigated cholera transmission, while Robert Koch advanced
bacteriological culture methods.
Keywords: John Graunt, Vital Statistics, History of Epidemiology
5. In his renowned 1854 investigation of the Broad Street cholera outbreak in London's Golden Square,
John Snow utilized a methodology that is widely recognized as the classic prototype of a:
A. Genomewide association study
B. Double-blind community trial
C. Natural experiment
D. Randomized controlled trial
Answer: C
Rationale: John Snow's comparison of cholera death rates between households served by the
Southwark and Vauxhall Company versus those served by the Lambeth Company constituted a classic
natural experiment, as water source exposure varied naturally without experimental intervention by the
,investigator. Snow mapped cases and demonstrated that Lambeth customers, whose intake had moved
upstream to less polluted water, experienced dramatically lower mortality. This observational design
laid the groundwork for modern analytical and field epidemiology.
Keywords: John Snow, Natural Experiment, Cholera, History of Epidemiology
6. Which nineteenth-century public health pioneer served as the British Compiler of Abstracts in the
General Register Office and developed a sophisticated system for classifying causes of death that laid
the foundation for the International Classification of Diseases (ICD)?
A. William Farr
B. Lemuel Shattuck
C. Ignaz Semmelweis
D. Edwin Chadwick
Answer: A
Rationale: William Farr systematically collected and analyzed national census and vital registration data
in England and Wales, pioneering modern disease classification and surveillance systems. He also
examined relationships between population density, occupational hazards, and mortality rates,
establishing quantitative standards for epidemiology. Lemuel Shattuck drafted an influential public
health report in Massachusetts, while Chadwick led sanitation reforms.
Keywords: William Farr, Classification of Diseases, Surveillance, Vital Statistics
7. In the 1840s, Ignaz Semmelweis observed that postpartum maternal mortality from puerperal fever
was substantially higher in the First Obstetric Clinic staffed by physicians and medical students
compared to the Second Clinic staffed by midwives. What intervention did he implement to address the
etiology of this disease?
, A. Mandatory handwashing with a chlorinated lime solution prior to patient examination
B. Boiling of all surgical instruments and immediate installation of carbolic acid sprayers
C. Complete quarantine of the obstetric ward and fumigation with sulfur dioxide
D. Administration of therapeutic doses of penicillin to all laboring patients
Answer: A
Rationale: Semmelweis hypothesized that medical students were transferring 'cadaverous particles'
from the autopsy room directly to laboring women during pelvic examinations. By enforcing mandatory
hand hygiene with a chlorinated lime solution, he reduced maternal mortality from over 10% to
approximately 1-2%, demonstrating the critical role of hand hygiene in controlling hospital-acquired
infections before the formal establishment of the germ theory. Antibiotics like penicillin were not
discovered until the twentieth century.
Keywords: Ignaz Semmelweis, Puerperal Fever, Hand Hygiene, Infection Control
8. Which of Robert Koch’s postulates requires that a suspected pathogenic agent, after being isolated
from a diseased host and grown in pure culture, must produce the specific disease when introduced into
a healthy, susceptible host animal?
A. Fourth postulate
B. Third postulate
C. Second postulate
D. First postulate
Answer: B
Rationale: Koch's third postulate stipulates that the microorganism isolated from the diseased animal
and grown in pure culture must reproduce the specific disease when inoculated into a susceptible
experimental host. The first postulate requires the organism to be present in every case, the second
requires pure culture isolation, and the fourth requires re-isolation of the agent from the experimentally
infected host. These criteria formed the cornerstone of the germ theory era of infectious disease
causation.
, Keywords: Koch's Postulates, Germ Theory, Causal Inference, Microbiology
9. Edward Jenner's development of the smallpox vaccine in 1796 represented an epochal milestone in
public health epidemiology because it demonstrated that:
A. Passive administration of synthetic antibodies confers permanent sterilizing immunity
B. Antibiotic prophylaxis could interrupt the spread of orthopoxviruses during acute outbreaks
C. Inoculation with cowpox material conferred cross-protective immunity against lethal smallpox
D. Variolation using active smallpox scabs could eliminate secondary community transmission
Answer: C
Rationale: Jenner observed that dairymaids exposed to mild cowpox (vaccinia) were protected against
severe smallpox (variola) infection. By inoculating young James Phipps with cowpox pustule matter and
later challenging him with smallpox, Jenner proved the efficacy of vaccination, ultimately leading to the
global eradication of smallpox in 1980. This was the first systematic application of immunologic
principles to prevent epidemic disease.
Keywords: Edward Jenner, Smallpox Eradication, Vaccination, History of Epidemiology
10. The 1918–1919 Influenza Pandemic exhibited an unusual epidemiological pattern that distinguished
it from typical seasonal influenza epidemics. What was this defining characteristic?
A. Peak mortality occurring predominantly among infants and adults over 65, mirroring the typical
seasonal influenza U-shaped mortality curve
B. Complete absence of morbidity or mortality among infants and elderly populations over age 65
C. Transmission occurred exclusively through contaminated municipal water supplies rather than
respiratory droplets
D. A unique 'W-shaped' age-specific mortality curve showing exceptionally high mortality among
Chapter 1: History and Scope of Epidemiology
Chapter 2: Practical Applications of Epidemiology
Chapter 3: Measures of Morbidity and Mortality Used in Epidemiology
Chapter 4: Descriptive Epidemiology: Person, Place, Time
Chapter 5: Sources of Data for Use in Epidemiology
Chapter 6: Measures of Effect
Chapter 7: Study Designs: Ecologic and Cross-Sectional
Chapter 8: Experimental Study Designs
Chapter 9: Confounding, Selection Bias, Information Bias: Threats to Internal Validity
Chapter 10: Study Designs: Cohort Studies
Chapter 11: Study Designs: Case-Control Studies
Chapter 12: Screening for Disease in the Community
Chapter 13: Epidemiology of Infectious Diseases
Chapter 14: Epidemiologic Aspects of Work and the Environment
Chapter 15: Molecular and Genetic Epidemiology
Chapter 16: Social, Behavioral, and Psychosocial Epidemiology
Chapter 17: Epidemiology as a Profession
Chapter 18: Epidemiology and Health Policy
,Chapter 1: History and Scope of Epidemiology
1. Which component of the formal definition of epidemiology refers to the systematic search for factors
or events capable of bringing about a change in health status?
A. Distribution
B. Surveillance
C. Determinants
D. Quantification
Answer: C
Rationale: In epidemiology, determinants encompass biological agents, chemical exposures,
socioeconomic factors, and lifestyle behaviors that directly influence or produce changes in health
status. Identifying determinants allows public health practitioners to design targeted interventions
aimed at primary prevention. Distribution, by contrast, describes the frequency and pattern of health
events by person, place, and time.
Keywords: Determinants, Definition of Epidemiology, Causation
2. A county health department notes that the baseline occurrence of Giardia infections in its jurisdiction
is approximately 4 cases per month. Over the past three weeks, 42 lab-confirmed cases have been
reported among residents who used a public municipal pool. This phenomenon is best classified as an:
A. Pandemic
, B. Epidemic
C. Hyperendemic equilibrium
D. Endemic baseline
Answer: B
Rationale: An epidemic is defined as the occurrence in a community or region of cases of an illness,
specific health-related behavior, or other health-related events clearly in excess of normal expectancy.
Because 42 cases over three weeks vastly exceeds the established background expectancy of 4 cases per
month, the event represents an epidemic (or localized outbreak). Endemicity refers strictly to the
habitual, ongoing presence of a disease within a given geographic area.
Keywords: Epidemic, Outbreak Investigation, Disease Frequency
3. Which of the following classical treatises marked a fundamental departure from supernatural
explanations of disease by proposing that environmental factors such as climate, water sources, and
geography influence illness?
A. Natural and Political Observations on the Bills of Mortality
B. Airs, Waters, and Places
C. De Contagione et Contagiosis Morbis
D. Micrographia
Answer: B
Rationale: Written by Hippocrates around 400 BCE, Airs, Waters, and Places established the
foundational epidemiologic observation that environmental conditions and human behaviors shape the
distribution of disease in populations. This work shifted medical thinking away from superstitious beliefs
toward empirical observation of nature and geography. John Graunt authored the Bills of Mortality
treatise two millennia later.
Keywords: Hippocrates, History of Epidemiology, Environmental Health
,4. John Graunt’s 1662 publication, *Natural and Political Observations Mentioned in a Following Index,
and Made upon the Bills of Mortality*, is considered foundational to modern epidemiology primarily
because it:
A. Established the first laboratory culture techniques for enteric bacteria
B. Identified the waterborne transmission mechanism of Vibrio cholerae
C. Formulated the modern four-phase framework for randomized clinical trials
D. Demonstrated the utility of quantitative vital statistics to identify population mortality patterns
Answer: D
Rationale: John Graunt was the first to systematically compile, quantify, and analyze weekly church
birth and death records (Bills of Mortality) in London, recording gender differences, infant mortality, and
seasonal variations. His pioneering work established demography and vital statistics as core quantitative
tools of epidemiology. John Snow later investigated cholera transmission, while Robert Koch advanced
bacteriological culture methods.
Keywords: John Graunt, Vital Statistics, History of Epidemiology
5. In his renowned 1854 investigation of the Broad Street cholera outbreak in London's Golden Square,
John Snow utilized a methodology that is widely recognized as the classic prototype of a:
A. Genomewide association study
B. Double-blind community trial
C. Natural experiment
D. Randomized controlled trial
Answer: C
Rationale: John Snow's comparison of cholera death rates between households served by the
Southwark and Vauxhall Company versus those served by the Lambeth Company constituted a classic
natural experiment, as water source exposure varied naturally without experimental intervention by the
,investigator. Snow mapped cases and demonstrated that Lambeth customers, whose intake had moved
upstream to less polluted water, experienced dramatically lower mortality. This observational design
laid the groundwork for modern analytical and field epidemiology.
Keywords: John Snow, Natural Experiment, Cholera, History of Epidemiology
6. Which nineteenth-century public health pioneer served as the British Compiler of Abstracts in the
General Register Office and developed a sophisticated system for classifying causes of death that laid
the foundation for the International Classification of Diseases (ICD)?
A. William Farr
B. Lemuel Shattuck
C. Ignaz Semmelweis
D. Edwin Chadwick
Answer: A
Rationale: William Farr systematically collected and analyzed national census and vital registration data
in England and Wales, pioneering modern disease classification and surveillance systems. He also
examined relationships between population density, occupational hazards, and mortality rates,
establishing quantitative standards for epidemiology. Lemuel Shattuck drafted an influential public
health report in Massachusetts, while Chadwick led sanitation reforms.
Keywords: William Farr, Classification of Diseases, Surveillance, Vital Statistics
7. In the 1840s, Ignaz Semmelweis observed that postpartum maternal mortality from puerperal fever
was substantially higher in the First Obstetric Clinic staffed by physicians and medical students
compared to the Second Clinic staffed by midwives. What intervention did he implement to address the
etiology of this disease?
, A. Mandatory handwashing with a chlorinated lime solution prior to patient examination
B. Boiling of all surgical instruments and immediate installation of carbolic acid sprayers
C. Complete quarantine of the obstetric ward and fumigation with sulfur dioxide
D. Administration of therapeutic doses of penicillin to all laboring patients
Answer: A
Rationale: Semmelweis hypothesized that medical students were transferring 'cadaverous particles'
from the autopsy room directly to laboring women during pelvic examinations. By enforcing mandatory
hand hygiene with a chlorinated lime solution, he reduced maternal mortality from over 10% to
approximately 1-2%, demonstrating the critical role of hand hygiene in controlling hospital-acquired
infections before the formal establishment of the germ theory. Antibiotics like penicillin were not
discovered until the twentieth century.
Keywords: Ignaz Semmelweis, Puerperal Fever, Hand Hygiene, Infection Control
8. Which of Robert Koch’s postulates requires that a suspected pathogenic agent, after being isolated
from a diseased host and grown in pure culture, must produce the specific disease when introduced into
a healthy, susceptible host animal?
A. Fourth postulate
B. Third postulate
C. Second postulate
D. First postulate
Answer: B
Rationale: Koch's third postulate stipulates that the microorganism isolated from the diseased animal
and grown in pure culture must reproduce the specific disease when inoculated into a susceptible
experimental host. The first postulate requires the organism to be present in every case, the second
requires pure culture isolation, and the fourth requires re-isolation of the agent from the experimentally
infected host. These criteria formed the cornerstone of the germ theory era of infectious disease
causation.
, Keywords: Koch's Postulates, Germ Theory, Causal Inference, Microbiology
9. Edward Jenner's development of the smallpox vaccine in 1796 represented an epochal milestone in
public health epidemiology because it demonstrated that:
A. Passive administration of synthetic antibodies confers permanent sterilizing immunity
B. Antibiotic prophylaxis could interrupt the spread of orthopoxviruses during acute outbreaks
C. Inoculation with cowpox material conferred cross-protective immunity against lethal smallpox
D. Variolation using active smallpox scabs could eliminate secondary community transmission
Answer: C
Rationale: Jenner observed that dairymaids exposed to mild cowpox (vaccinia) were protected against
severe smallpox (variola) infection. By inoculating young James Phipps with cowpox pustule matter and
later challenging him with smallpox, Jenner proved the efficacy of vaccination, ultimately leading to the
global eradication of smallpox in 1980. This was the first systematic application of immunologic
principles to prevent epidemic disease.
Keywords: Edward Jenner, Smallpox Eradication, Vaccination, History of Epidemiology
10. The 1918–1919 Influenza Pandemic exhibited an unusual epidemiological pattern that distinguished
it from typical seasonal influenza epidemics. What was this defining characteristic?
A. Peak mortality occurring predominantly among infants and adults over 65, mirroring the typical
seasonal influenza U-shaped mortality curve
B. Complete absence of morbidity or mortality among infants and elderly populations over age 65
C. Transmission occurred exclusively through contaminated municipal water supplies rather than
respiratory droplets
D. A unique 'W-shaped' age-specific mortality curve showing exceptionally high mortality among
