What term describes a disease being present endemically in certain populations?

The term that describes a disease being present endemically in certain populations is "enzootic." This term is specifically used to indicate that a disease is consistently maintained in a particular animal population without the need for external inputs, meaning the disease has a stable presence in that population over time.

In public health and veterinary contexts, "enzootic" typically refers to diseases that are regularly found among particular species in specific regions. For example, if a certain infectious disease is consistently reported among deer populations in a forested area, it can be described as enzootic to that population.

Other terms like "epizootic," "hyperendemic," and "sylvatic" refer to different scenarios. While epizootic means a disease outbreak that occurs at a level above what is normally expected within a population, hyperendemic refers to a continuously high incidence of a disease that is higher than baseline levels but not necessarily at epidemic levels. Sylvatic pertains to diseases that occur in wild animal populations, potentially spilling over to domestic species or humans, but does not specifically imply a consistent presence in the same way that enzootic does.