Reservoir

Definition

A population, species, or environment in which a pathogen naturally persists and multiplies, serving as a source of infection for other organisms. In disease ecology, the reservoir maintains the pathogen independently of spillover hosts and enables transmission cycles that may involve vectors.

Etymology

French réservoir, from réserver (to reserve)

Example

The white-footed mouse (Peromyscus leucopus) is the primary reservoir for Borrelia burgdorferi, the spirochete that causes Lyme disease, which is then transmitted to humans by Ixodes scapularis ticks.

Synonyms

• natural host
• maintenance host

Related Terms

• Vector
• spillover host
• amplifying host
• dead-end host
• Zoonosis
• enzootic

Usage Notes

Distinguished from a vector (which transmits but does not necessarily maintain the pathogen) and from an amplifying host (which increases pathogen numbers but cannot sustain transmission alone). Reservoir status is often context-dependent; a species may be a reservoir in one ecosystem but not another. The term is sometimes extended to environmental reservoirs (soil, water) for environmentally persistent pathogens.