What is the term for how pathogens spread to new hosts?

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

Answer: (A)

Understanding how pathogens spread from one person to another centers on the route or mechanism of transfer. The term for this is mode of transmission, which describes the path the pathogen takes to move to a new host—whether through direct contact, droplets, airborne particles, contaminated surfaces (fomites), food or water (vehicles), or vectors like mosquitoes.

Portal of exit, on the other hand, is where the pathogen leaves the current host, such as respiratory droplets when coughing, blood, or other secretions. Portal of entry is how the pathogen gets into the next host, like through the nose, mouth, or breaks in the skin. A susceptible host refers to the person who could become infected, due to factors like lack of immunity, age, or health status.