In the chain of infection, which component describes the route by which the pathogen leaves the reservoir?

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

Answer: (D)

In the chain of infection, after a pathogen resides in a reservoir, it must leave that reservoir to reach another host. The term that describes the route it uses to exit is the portal of exit. This includes things like droplets from coughing or sneezing, blood from a wound, feces or urine, or secretions from a lesion—any pathway that carries the pathogen away from its current place of existence. The other terms refer to different parts of the process: the portal of entry is how the pathogen enters a new host, the reservoir is where the pathogen lives, and the mode of transmission is the method by which the pathogen is carried from one host to another. So the exit route from the reservoir is the portal of exit.