Which of the following correctly orders the steps a microorganism typically takes in establishing disease in a host?

• A. Adherence, entry, multiplication, invasion, damage to host tissues, evasion of host defenses
• B. Evasion of host defenses, entry, adherence, multiplication, invasion, damage to host tissues
• C. Multiplication, entry, adherence, evasion of host defenses, invasion, damage to host tissues
• D. Entry, adherence, invasion, multiplication, evasion of host defenses, damage to host tissues

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the general process of pathogenesis, which is how a microorganism causes disease in a host. This process typically follows a sequence of events starting from the microorganism entering the host to causing damage.
2. Step 2: Identify the initial step as 'entry,' where the microorganism gains access to the host through a portal such as the respiratory tract, skin, or mucous membranes.
3. Step 3: Next is 'adherence,' where the microorganism attaches to host cells using specific structures like pili or adhesins, which is crucial for colonization and preventing removal.
4. Step 4: Then comes 'invasion,' where the microorganism penetrates host tissues or cells to establish infection beyond the initial site of entry.
5. Step 5: After invasion, the microorganism undergoes 'multiplication,' increasing its numbers within the host, followed by 'evasion of host defenses,' where it avoids or resists the immune response, and finally causes 'damage to host tissues,' leading to disease symptoms.