What is fever? Fever is one of the body’s most original defenses against infection or assault. The technical definition, for medical practitioners, defines this as a core body temperature of 100.4-100.9 F, which is about 3 degrees higher than what is considered a normal temperature. Other terms, such as hyperthermia and pyrexia, are also used interchangeably, although the understanding of these two terms does not have any precise definition. However, what is more useful and interesting to understand is what causes a fever and why it is occurring.
What causes fever?
When the body notices a foreign intruder, such as bacteria (known as sepsis), it releases tiny components of the immune system that act on the brain as a signal to increase temperature. This area of the brain is always in direct contact with circulating blood in the body, which renders it capable of performing this form of surveillance.
Sometimes, toxins produced by bacteria can act on this area of the brain directly to trigger this response. This is actually a very fine-tuned evolutionary mechanism, raises temperatures above what bacteria and fungi can survive without harming body cells themselves, as well as allows for key parts of the immune system to become widely circulated. In a fortunate coincidence, antibiotic drugs also work better at these higher temperatures.