98.6 is body temperature on which scale?

herb198220, I agree with your idea but would say it differently. A fever is the body's reaction (also a symptom) to an infection. The body doesn't, so much fight infection better at high temperatures, but the infectious organism will die at these temperatures.

Temperature varies by gender, time of day, etc. "Normal" human body temperature has been decreasing since the 1800s, and is now around 97.5°F (36.4°C).