PBH 452 Midterm Practice Exam Review

Vocabulary practice flashcards covering key public health and epidemiology concepts from the PBH 452 midterm practice exam, including infectious disease transmission, measures of frequency and mortality, levels of prevention, screening test validity, and historical milestones.

Active Immunity

Long-duration immunity achieved through an antigen injection (such as Dtap or Tdap vaccines) that actively stimulates antibody formation in the host rather than providing innate antibodies.

Host (Epidemiologic Triad)

The component of the epidemiologic triad that encompasses intrinsic factors and biological characteristics of an individual, including their vaccination status.

Incidence Density

An epidemiologic measure of disease frequency that uses person-time in its denominator and is primarily used for open (dynamic) populations rather than closed populations.

Secondary Prevention

Preventive activities focused on early detection and screening of subclinical disease during the pathogenesis phase, such as performing an echocardiography screening test during a primary care physician appointment.

Primary Prevention

Interventions implemented prior to disease onset—such as diet modifications and physical activity improvements—that work to reduce both the incidence and prevalence of a condition.

Dr. Ignaz Semmelweis's Observation

The epidemiologic finding associating childbed fever among mothers in the General Hospital in Vienna with bacteria on physicians' medical tools after working with corpses.

Doll and Hill Smoking Finding

The epidemiologic finding demonstrating that frequent and heavy smokers—not occasional smokers—were substantially more likely to contract lung cancer.

Disease-Specific Mortality Rate

A mortality rate measuring deaths due to a specific condition, utilizing the total mid-year population as its denominator (identical to the denominator for the crude death rate).

Period Prevalence

An epidemiologic measure of frequency that quantifies existing cases of a disease over a defined period of time divided by the total population.

Incidence Rate (Open Population)

The recommended measure of disease occurrence for newly diagnosed cases occurring within a large, dynamic, or open population.

Maternal Mortality Rate

The number of deaths specifically attributable to childbirth-related complications among mothers, excluding general maternal deaths caused by unrelated infections like pneumonia.

Mortality Effect on Disease Prevalence

An inverse relationship where an increase in deaths due to a particular illness (such as influenza type A) removes affected cases from the population, thereby decreasing prevalence.

Biological Vector

A living organism (such as a sandfly) that transmits an infectious agent to a host, distinct from an inanimate fomite.

Crude Attack Rate

An epidemiologic measure of frequency used in outbreak investigations of closed, small populations, where the numerator is the total number of exposed individuals who fell ill.

Pathogenesis Phase Associations

The stages and interventions occurring after disease processes initiate, specifically encompassing secondary prevention and the subclinical phase.

John Snow's Observation

The historical public health investigation establishing a strong causal association between contaminated municipal water supplies and cholera.

Infant Mortality Rate

The total number of deaths occurring among infants between the ages of $0$ and $365\text{ days}$ ($0$ to $1\text{ year}$ of life).

True Negative (TN)

A screening result where the diagnostic test identifies an individual as negative and the individual is confirmed to have no evidence of the disease.

Validity Rates with True Negatives in Numerator

The two diagnostic performance measures that include true negatives in their numerators: Specificity and Negative Predictive Value (NPV).

Validity Rates with True Positives in Numerator

The two diagnostic performance measures that include true positives in their numerators: Sensitivity and Positive Predictive Value (PPV).

Negative Predictive Value (NPV)

The probability that a patient who tests negative on a screening test truly does not have the disease (e.g., an $85\%$ NPV indicates an $85\%$ probability of being truly disease-free).