Within the chain of infection, what is the reservoir?

• A. The susceptible host that lacks effective immunity to the pathogen
• B. The portal of exit through which a pathogen leaves the host (e.g., respiratory secretions, blood)
• C. The mode of transmission by which a pathogen spreads (e.g., contact, droplet, airborne)
• D. The natural habitat (human, animal, or environment) in which a pathogen normally lives, grows, and multiplies

Answer: (D)

Verified step by step guidance

1. Understand that the chain of infection consists of several key components: the infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host.
2. Identify the reservoir as the natural habitat where the pathogen normally lives, grows, and multiplies. This can be a human, animal, or environmental source.
3. Distinguish the reservoir from other components: the susceptible host is the organism that can be infected; the portal of exit is how the pathogen leaves the host; and the mode of transmission is how the pathogen spreads.
4. Recognize that the reservoir is crucial because it maintains the pathogen in nature and serves as the source from which infection can spread to new hosts.
5. Summarize that the reservoir is not the host that gets infected or the way the pathogen moves, but specifically the environment or organism where the pathogen thrives before transmission.