Which of the following does NOT describe a susceptible host in the context of microbiology?

• A. An elderly person with chronic health conditions
• B. A person who has been vaccinated against the pathogen
• C. A newborn infant with immature immunity
• D. An individual with a weakened immune system

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the term 'susceptible host' in microbiology. A susceptible host is an individual who is vulnerable to infection by a pathogen due to factors like weakened immunity, age, or health conditions.
2. Step 2: Analyze each option to determine if it describes a susceptible host. Consider whether the person’s immune system or protective factors make them vulnerable to infection.
3. Step 3: Evaluate 'An elderly person with chronic health conditions' — such individuals often have weakened immune defenses, making them susceptible hosts.
4. Step 4: Evaluate 'A newborn infant with immature immunity' — newborns have underdeveloped immune systems, so they are typically susceptible hosts.
5. Step 5: Evaluate 'A person who has been vaccinated against the pathogen' — vaccination usually provides immunity, reducing susceptibility, so this option does NOT describe a susceptible host.