Which factor does NOT contribute to a susceptible host?

• A. Malnutrition
• B. Chronic disease
• C. High level of immune function
• D. Advanced age

Answer: (C)

A susceptible host becomes more likely to develop infection when defenses are weakened. A high level of immune function is protective, so it does not contribute to susceptibility. Malnutrition compromises immune cell function and skin and mucosal barriers, increasing infection risk. Chronic disease can impair immune responses and tissue perfusion, creating opportunities for pathogens to establish infection. Advanced age is associated with immunosenescence and diminished physiological reserves, which also raise susceptibility. In short, a strong immune system helps prevent infections, while poor nutrition, chronic illness, and aging raise the likelihood of becoming susceptible.