Believe it or Not, Your Fever Can be Useful

A fever, that hot, burning sensation often present as a result of illness is generally thought of only as an annoyance. We take medication to rid ourselves of fevers, and use the fever as a method of identifying our sickness. Yet there is more to a fever than a mere bodily reaction to microbial invasion, a signal and symptom of illness. A fever is also a means by which the body deals with foreign invaders in the body. In all actuality fevers are stimulated by part of the body's second line of defense. To be more precise, pyrogens are responsible for causing a fever during a microbial attack.

When exposed to bacteria, macrophages are released into the body where they travel to the hypothalamus, a section of the brain that controls the body's temperature, among other things. Here, the pyrogens stimulate an increase in body temperature or cause a fever, if you will. In a little more detail, pyrogens create a sensation of being cold which the brain responds to by raising the body's temperature (). When moderate, this fever is helpful to the body in fighting the infection and in returning the body to normal. However, it is important to note that high fevers (generally around 105 degrees) can cause serious damage to the body and must be treated. A moderate fever, which often accompanies a flu and other common illnesses, is actually quite beneficial to the body.

A moderate fever stimulates the liver and spleen causing them to remove additional amounts of iron from the blood (Chiras, 2005). Why is the removal of iron so critical to the body's defenses? The process of taking additional iron from the body aids in defense against invaders because a great deal of bacteria use iron in their reproductive process. As such, the removal of it from the body creates a situation in which it is harder for disease-causing bacteria to reproduce and flourish in the body.
Secondly, a fever increases the body's metabolic rate which serves two purposes. The first of these is to accelerate the of cellular defenses such as phagocytosis (Chiras, 2005). Phagocytosis is the process by which microorganisms and cell fragments are eaten and digested by macrophages. Thus, an increase in metabolic rate increases the amount and rate of microorganisms that are eliminated by phagocytosis. Additionally, an increased metabolism increases the rate of healing experienced by the body. The same is true for wounds in which histamines are released and heats the wounded area which in turn aids in accelerating the healing process.

References:

Chiras, D, D. (2005). Human Biology, 5^th Edition. Sudbury, Mass., Jones and Bartlett Publishers. Pg 266 - 267.

"La Fièvre" by Matthew J. Kluger, La Recherche 12: 688-696, 1981

*Retrieved March 25, 2008, from http://www.pbs.org/wgbh/evolution/library/10/4/l_104_04.html

PBS. (2001). Function of Fever. Retrieved March 25, 2008, from http://www.pbs.org/wgbh/evolution/library/10/4/l_104_04.html