Consistently present at an expected or characteristic level within a particular population, geographic area, or setting.
A disease is described as endemic when it is regularly found in a particular population or region at a level that is considered expected for that setting. The term describes the usual pattern of occurrence, not whether the disease is mild, severe, dangerous, or contagious.
For example, malaria is endemic in many parts of sub-Saharan Africa, where transmission occurs regularly. This does not mean that every person has malaria or that the number of cases is constant; transmission and case numbers can vary over time while the disease remains endemic.
QUICK FACT
Endemic does not mean “harmless” or “always present in the same number.” It means the disease occurs at an expected or established level in a particular setting.
COMMONLY CONFUSED WITH
- Epidemic: occurrence above the level normally expected in a population, place, or period.
- Pandemic: an epidemic that spreads across multiple countries or continents and affects a large population.
- Outbreak: a localized increase in cases above what is normally expected.
SEE ALSO