An infection constantly maintained at a baseline level in a geographic

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

Endemic
Pandemic
Epidemic
Outbreak
This question was previously asked in
UPSC CDS-2 – 2021
An endemic infection refers to the constant presence and/or usual prevalence of a disease or infectious agent in a population within a geographic area.
The key characteristic of an endemic disease is that it is maintained at a predictable baseline level within a specific region without needing external introduction.
An epidemic is a sudden increase in the number of cases of a disease in a population in a geographical area exceeding the expected level. A pandemic is an epidemic that spreads across multiple continents or worldwide. An outbreak is a more localized or limited increase in disease incidence compared to the expected level.