Module SS1978: Principles of Epidemiology in Public Health Practice Flashcards

These flashcards cover the fundamental principles, historical evolution, data summarization techniques, measures of risk, and outbreak investigation steps as outlined in the CDC SS1978 course materials.

What is the formal definition of epidemiology?

The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems.

Who is considered the 'father of field epidemiology' for his work during the 1854 cholera outbreak?

John Snow

What are the five 'W’s' used to characterize epidemiologic events?

What (diagnosis), Who (person), Where (place), When (time), and Why/How (causes, risk factors, and modes of transmission).

What is the difference between descriptive and analytic epidemiology?

Descriptive epidemiology characterizes health events by time, place, and person, while analytic epidemiology searches for determinants (causes/factors) using a comparison group.

What are the three components of the epidemiologic triad?

External agent, susceptible host, and an environment that brings the host and agent together.

How do you calculate a disease rate?

Divide the number of cases by the size of the population per unit of time.

What is a case definition?

A set of standard criteria for classifying whether a person has a particular disease, syndrome, or other health condition.

What is the difference between a sensitive and a specific case definition?

A sensitive (loose) definition is used to capture all possible cases, while a specific (strict) definition is used to ensure those included truly have the disease.

Name the four types of variables based on scales of measurement.

Nominal (categories), Ordinal (rankable categories), Interval (measured units no zero), and Ratio (measured units with a true zero).

What is the difference between a point-source epidemic and a propagated epidemic?

A point-source epidemic involves exposure to the same source over a brief period (all cases within one incubation period), while a propagated epidemic involves person-to-person spread.

Define 'Prevalence' in contrast to 'Incidence'.

Prevalence includes all cases (new and preexisting) at a specific time, whereas incidence refers ONLY to new cases over a specified period.

What is 'Years of Potential Life Lost' (YPLL)?

A measure of the impact of premature mortality on a population, calculated as the sum of differences between a predetermined end point (like age 65) and the age of death.

What is the 'hallmark' of an analytic epidemiologic study?

The use of a valid comparison group.

What is a 'spot map' used for in an investigation?

To show the geographic distribution of cases by residence or exposure site, though it does not take population density into account.

Define 'Public Health Surveillance'.

The ongoing, systematic collection, analysis, interpretation, and dissemination of health data to guide public health decision-making and action.

What is the 'Chain of Infection'?

The process where an agent leaves its reservoir through a portal of exit, is conveyed by a mode of transmission, and enters a portal of entry to infect a susceptible host.

What are the three components of Rothman’s 'Causal Pies' model?

Component causes (individual factors), sufficient causes (the complete set of factors resulting in disease), and necessary causes (a component appearing in every pie).

How does a cohort study differ from a case-control study?

A cohort study groups participants based on exposure and follows them for outcomes; a case-control study groups participants based on disease status and looks back at their exposures.

What is 'Syndromic Surveillance'?

Monitoring frequency of clinical feature constellations (syndromes) rather than laboratory-confirmed diagnoses to provide earlier indications of unusual disease increases.

What are the common measures of central location?

Arithmetic mean, median, mode, midrange, and geometric mean.