Which component of the chain of infection is the place where the pathogen lives and multiplies?

• A. Reservoir
• B. Portal of Exit
• C. Portal of Entry
• D. Mode of Transmission

Answer: (A)

The main idea here is identifying where a pathogen actually grows and reproduces. That place is the reservoir. The reservoir can be a person, an animal, or an environment (like soil, water, or a contaminated surface) where the organism can survive, multiply, and persist. Controlling infections often focuses on reducing or eliminating the pathogen in its reservoir to break the chain of transmission.

The other options describe different links in the chain: the portal of exit is where the pathogen leaves the reservoir; the portal of entry is how it enters a new host; and the mode of transmission is the method by which it moves from one place or person to another (such as direct contact, droplets, airborne spread, vectors, or vehicles).