While being a troubling change in one’s health, fever is a mechanism that protects the human body. Fever can be characterized as a temporary increase in body temperature and serves as a defense response against infection. Although it may seem that fever worsens an individual’s condition, it is meant to fight for the person’s well-being. For instance, fever leads to a considerable loss in calories and dehydrates the system, but it also creates an environment within the body that is more uncomfortable for pathogens than for humans.
Fever helps the organism affected by an infection by causing trouble for microbes’ survival via high temperatures. An adult typically develops a fever when body temperature increases from approximately 99°F to about 99.5°F. A child exhibits a fever when their temperature is above 99.5°F when measured orally. A variety of microorganisms thrive within the body when it is at its normal temperature. However, it is harder for bacteria and viruses to survive at lower temperatures because an environment below 98.6°F provides good conditions for the replication and infection of cells. In addition, fever results in better activation of the immune system. For example, dendritic cells, neutrophils, and macrophages, which are considered the first respondents to illness, travel significantly faster to the infected area under higher temperatures. Moreover, fever can facilitate the generation and efficiency of T-cells that contribute to long-term immune responses, like antibody production. Therefore, while being considered a negative symptom, fever helps the human body fight infection in two ways. An increase in body temperature caused by fever makes it difficult for microbes to reproduce, while the immune system operates and defends better under a higher temperature.