Why does an individual have high fever when there is an infection?

1 Answer
Oct 3, 2017

The hypothalamic brain center regulating body temperature is upset by certain types of infections.

Explanation:

Fever can help fight infection.
https://www.scientificamerican.com/article/what-causes-a-fever/

Fever is the body’s natural response to infection. A part of the brain called the hypothalamus raises the body temperature to create an environment that is unfavorable for the bacteria or viruses that cause infectious disease. For example, the viruses that cause colds and other respiratory infections thrive at cool temperatures. One way the body works to eliminate a virus is by producing a fever.
https://www.texasoncology.com/cancer-treatment/side-effects-of-cancer-treatment/common-side-effects/feverinfection/

Fever is elevated body temperature (> 37.8° C orally or > 38.2° C rectally) or an elevation above a person’s known normal daily value. Fever occurs when the body's thermostat (located in the hypothalamus) resets at a higher temperature, primarily in response to an infection. Elevated body temperature that is not caused by a resetting of the temperature set point is called hyperthermia.

Normally, the hypothalamic thermoregulatory center maintains the internal temperature between 37° and 38° C. Fever results when something raises the hypothalamic set point. These processes continue until the temperature of the blood bathing the hypothalamus reaches the new set point. Resetting the hypothalamic set point downward (eg, with antipyretic drugs) initiates heat loss through sweating and vasodilation.

The capacity to generate a fever is reduced in certain patients (eg, alcoholics, the very old, the very young).

Although many patients worry that fever itself can cause harm, the modest transient core temperature elevations (ie, 38 to 40°) caused by most acute illnesses are well tolerated by healthy adults.

http://www.merckmanuals.com/professional/infectious-diseases/biology-of-infectious-disease/fever