Which statement about the chain of infection is NOT true?

• A. It includes portals of entry and exit, a reservoir, and an infectious agent.
• B. It requires a susceptible host.
• C. It can occur without any infectious agent present.
• D. It describes how infections spread from person to person.

Answer: (C)

The chain of infection rests on six connected links: an infectious agent, a reservoir, a portal of exit, a mode of transmission, a portal of entry, and a susceptible host. For infection to occur, every link must be present and capable of functioning. If there is no infectious agent at all, there is nothing to cause disease or to spread, so the chain cannot be completed. That’s why saying it can occur without any infectious agent present isn’t true. The other statements align with how the chain works: it includes portals of entry and exit, a reservoir, and an infectious agent; it requires a susceptible host; and it describes how infections spread from one person to another or through other transmission routes.