Exit portal is the term for where a microorganism leaves its reservoir. Which option correctly identifies this?

• A. Mode of transmission
• B. Exit portal
• C. Reservoir
• D. Entry portal

Answer: (B)

The main idea here is understanding the terminology for how pathogens move from one host or environment to another. The exit portal is the site through which a microorganism leaves its reservoir to reach a new host. This distinguishes it from other terms: the reservoir is where the organism normally lives or persists; the entry portal is where the organism enters a new host; and the mode of transmission describes the mechanism by which the organism is spread between hosts (for example, droplet, contact, airborne, vector, or vehicle transmission).

So, if a pathogen leaves the reservoir through the mouth or nose in droplets during coughing or sneezing, that route is the exit portal, while the droplets themselves participate in the mode of transmission to a new host.