Natural reservoir

In infectiousdisease ecology and epidemiology, a natural reservoir, also known as a disease reservoir or a reservoir of infection, is the population of organisms or the specific environment in which an infectious pathogen naturally lives, persists, and reproduces, or upon which the pathogen primarily depends for survival. A reservoir is usually a living host of a particular species, such as an animal, human, or plant, within which the pathogen survives, often without causing severe disease in the reservoir itself. By some definitions, a reservoir may also be an environment external to an organism, such as contaminated water, soil, or air, if the pathogen can persist there long enough to contribute to transmission.

Because of the diversity of infectious microorganisms, their host ranges, and the different ecological systems in which they circulate, definitions of a natural reservoir are numerous and sometimes conflicting. In general, the reservoir concept applies most clearly to pathogens capable of infecting more than one host population and is defined relative to a target population, meaning the population in which disease occurrence is being studied or controlled. The reservoir is any population of organisms, or in some cases any environment, in which the pathogen is maintained and from which infection is transmitted to the target population. Reservoirs may involve one or more species, may be the same as or different from the target population, and in broad usage may overlap with vector based transmission systems, although vectors are generally considered distinct from reservoirs.

Identifying the natural reservoirs of infectious pathogens is important for preventing and controlling outbreaks in humans and domestic animals, particularly for zoonotic diseases and for diseases without effective vaccines. In some settings, reservoir directed interventions such as animal vaccination, reduction of human exposure, environmental remediation, or vector control may reduce transmission. However, identifying a true reservoir can be difficult, and for some pathogens, including the ebolaviruses, the presumed reservoir remains uncertain.