Key Terms
Epidemiology
The study of geographical distribution and timing of infectious disease; includes etiology (study of causes) and investi
Etiology
Study of the causes of disease.
Population
The group of individuals at risk for a disease or condition. May be defined geographically or by behavior, institution,
Morbidity
State of being diseased.
Mortality
Death. Mortality rate expressed as percentage of population that died from a disease, or as deaths per 100,000 (or other
Prevalence
Number or proportion of individuals with a disease in a population AT A POINT IN TIME.
Incidence
Number or proportion of NEW cases in a specified time period.
Sporadic disease
Occurs rarely; no geographic concentration; cases in isolation.
Endemic disease
Constantly present in a specific geographic population.
Epidemic disease
Higher than expected cases in a short time in a geographic region.
Pandemic disease
Epidemic on a worldwide scale.
Robert Koch
First scientist to specifically demonstrate the causative agent of a disease (anthrax, late 1800s). Developed Koch's pos
CDC (Centers for Disease Control and Prevention)
Main national public health agency in the U.S.; part of the Department of Health and Human Services. Oversees the Nation
Notifiable diseases (also
Reportable diseases): diseases of public health importance that all cases must be reported to the CDC. Physicians treati
MMWR (Morbidity and Mortality Weekly Report)
Published by CDC; provides health-care workers with updates on public health issues and the latest data on notifiable di