Certification Board of Infection Control and Epidemiology (CBIC) Practice Exam 2025 – The All-in-One Guide for Exam Success

The chain of infection consists of several components that are critical for understanding how infections spread. The primary components include the infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host.

In this context, the mode of elimination does not fit into the established structure of the chain of infection. While interventions to eliminate an infectious agent or break the chain at various points are essential in infection control, the term "mode of elimination" is not officially recognized as one of the components of the chain itself.

Each of the other choices—infectious agent, reservoir, portal of exit—represents a key step in the chain that outlines the process of transmission of pathogens. The infectious agent is the organism responsible for the infection, the reservoir is where the organism lives and multiplies, and the portal of exit is the route through which the agent leaves its host to reach another susceptible individual.

Understanding these components aids in identifying ways to interrupt the chain of infection effectively, whereas "mode of elimination" does not characterize how infections propagate or disseminate. Therefore, recognizing that "mode of elimination" is not a component of the chain of infection effectively clarifies its role within the broader context of infection control measures.