Which term best describes the route by which an infectious agent leaves its reservoir?

• A. Portal Of Entry
• B. Mode Of Transmission
• C. Infectious Agent
• D. Portal Of Exit

Answer: (D)

Infection control hinges on the chain of infection, where the microbe must exit its original location to reach a new host. The route it uses to leave the reservoir is called the portal of exit. For example, pathogens can exit via coughing or sneezing droplets from the respiratory tract, through blood from a wound, or in saliva. Recognizing these exit routes helps us target prevention—blocking or reducing the opportunity for a microbe to leave the source with measures like masks, gowns, gloves, and proper handling of contaminated materials. The other terms describe different steps: the portal of entry is how the agent enters a new host, the mode of transmission is the method by which it moves from reservoir to host (such as direct contact or airborne spread), and the infectious agent is the microorganism itself.