Which sequence best describes how an infectious disease establishes itself in a host?

• A. Enter the host body, invade and colonize tissues, adhere to host cells, and inflict damage.
• B. Enter the host body, adhere to specific host cells, invade and colonize host tissues, and inflict damage.
• C. Adhere to host cells, invade tissues, enter the host, and inflict damage.
• D. Invade tissues, enter the host, adhere to cells, and cause damage.

Answer: (B)

The sequence starts with the pathogen gaining entry into the body, which is the first step that allows it to access internal tissues. After entry, the pathogen must attach to specific host cells to establish itself and resist being cleared by bodily defenses. This attachment sets up a stable foothold and often determines which tissues the pathogen will infect. Next comes invasion and colonization of the tissues, where the pathogen replicates and spreads within the host. Finally, damage to the host occurs as a result of the pathogen’s activities, such as toxin production and the host’s immune response causing tissue injury.

That makes the chosen sequence the best fit because it follows the logical progression from entry to attachment to tissue invasion, culminating in damage. Other sequences misplace these steps (for example, attempting to adhere before entering or invading before establishing attachment), which doesn’t align with how infections are typically established.