Public Health

Sporadic

• Diseases that occur infrequently or irregularly, they are so rare that a single case warrants an investigation (i.e. polio)

Endemic

• The baseline level of a particular disease that is usually present in a community
• Not necessarily a desired level (a disease can be endemic at high levels of occurrence)
• It typically has a constant presence in a population, or predictable cycles in a geographic area
• It is the expected level of disease without mitigations

Outbreak

• The amount of disease in the community rises above the expected level in a specific or limited geographic area (neighborhood, city, county, state) or from a specific event or gathering

Epidemic

• The amount of disease in the community rises above the expected level across a widespread geographic area (usually entire regions or countries)

Pandemic

• An epidemic that has spread over several countries or continents, usually affecting a large number of people