An infection constantly maintained at a baseline level in a geographic area without external input is known as

An infection that is constantly maintained at a baseline level within a specific geographic area without external input is defined as endemic. In epidemiology, 'endemic' refers to the constant presence or usual prevalence of a disease or infectious agent in a population within a geographic area. Unlike an epidemic, which represents a sudden increase in cases above what is normally expected [1], an endemic disease exists at a steady and predictable level. When the infection rate is maintained such that each infected person, on average, infects one other individual, an endemic equilibrium is reached. In contrast, an outbreak or epidemic involves a spike in cases, and a pandemic is an epidemic that has spread across multiple countries or continents [1]. Examples of endemic diseases include malaria in specific tropical regions.

Sources

1. [1] https://archive.cdc.gov/www_cdc_gov/csels/dsepd/ss1978/lesson1/section11.html