What is the adaptive value of fever in infection?

• A. Fever may enhance immune function, inhibit pathogen replication, and promote leukocyte activity, though it is not universal.
• B. Fever is harmful in all infections and should be suppressed immediately.
• C. Fever has no impact on immune response but causes dehydration.
• D. Fever accelerates pathogen replication.

Answer: (A)

Fever is an organized host response that raises the body’s temperature to help defend against infection. By increasing the hypothalamic set-point through pyrogens, the body creates a fever-range environment that can boost immune performance while making the external environment less favorable for many pathogens. Higher temperatures improve how immune cells work: neutrophils and macrophages become more active in engaging microbes, phagocytosis and microbial killing are more efficient, and lymphocytes proliferate and function more effectively, with heat-shock proteins aiding antigen presentation and communication among immune cells. At these temperatures, many pathogens also replicate more slowly, giving the immune system a better chance to clear the infection. This advantage is balanced by the fact that fever isn’t beneficial in every infection or patient—there are risks with excessive fever and some pathogens may not be hindered by higher temperatures—but the overall adaptive value lies in boosting immune defenses and limiting pathogen growth.