What is the correct sequence for the chain of infection?

Prepare for the Nurse Aide I Module B – Infection Prevention Test. Leverage multiple choice questions, detailed flashcards, and comprehensive explanations. Ensure your readiness for the exam!

Multiple Choice

What is the correct sequence for the chain of infection?

The sequence starts with the infectious agent and moves through the steps that allow it to spread to a new person. It begins with the infectious agent existing in a reservoir—where it can live and multiply—then the agent must exit the reservoir through a portal of exit. After leaving, it is transmitted to another person via a mode of transmission. Once it reaches a new person, it must enter through a portal of entry, and the person must be susceptible for infection to occur. Think of influenza as an example: the influenza virus lives in an infected person (the reservoir). It exits through the person’s nose or mouth when they cough or sneeze (portal of exit). The virus then travels through the air as droplets or via contaminated surfaces (transmission). Another person breathes in the droplets or touches their mouth or nose after touching the surface (portal of entry). If that person is not immune or protected (susceptible host), they can become infected. This order makes sense because each step depends on the previous one: without an agent, there’s nothing to exit; without an exit, there’s nowhere for transmission to begin; without transmission, a new host isn’t exposed; without entry, exposure doesn’t lead to infection; and without a susceptible host, infection doesn’t occur.

The sequence starts with the infectious agent and moves through the steps that allow it to spread to a new person. It begins with the infectious agent existing in a reservoir—where it can live and multiply—then the agent must exit the reservoir through a portal of exit. After leaving, it is transmitted to another person via a mode of transmission. Once it reaches a new person, it must enter through a portal of entry, and the person must be susceptible for infection to occur.

Think of influenza as an example: the influenza virus lives in an infected person (the reservoir). It exits through the person’s nose or mouth when they cough or sneeze (portal of exit). The virus then travels through the air as droplets or via contaminated surfaces (transmission). Another person breathes in the droplets or touches their mouth or nose after touching the surface (portal of entry). If that person is not immune or protected (susceptible host), they can become infected.

This order makes sense because each step depends on the previous one: without an agent, there’s nothing to exit; without an exit, there’s nowhere for transmission to begin; without transmission, a new host isn’t exposed; without entry, exposure doesn’t lead to infection; and without a susceptible host, infection doesn’t occur.

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