Which term is part of the cycle of disease?

• A. Elimination
• B. Isolation
• C. Reservoir
• D. Recovery

Answer: (C)

The chain of infection explains how disease spreads, and a reservoir is the place where a pathogen lives and multiplies. This reservoir—whether in humans, animals, or the environment—provides the environment the pathogen needs to survive and reproduce, which keeps transmission possible to a susceptible host. Without a reservoir, the organism can’t persist in the population, so the spread cannot continue.

Elimination refers to reducing disease incidence to zero in a population, which is a public health goal rather than a part of the disease transmission process. Isolation is a control action that separates infected individuals to prevent spread, not a stage in the pathogen’s life cycle. Recovery is the host’s return to health, an outcome rather than a step that enables ongoing transmission. Thus, the reservoir is the element that fits into the cycle.