Homeostasis and Fever

My youngest cousin, Mia, is 4 years old. She gets sick quite a lot during this time of the year; and gets fevers regularly.
I always though of fever as a disease, something harmful to your body. And yes, it can be harmful if the fever gets too high for too long, but it is actually something your body does to protect itself.
Homeostasis is the body's ability to adjust it's internal environment to maintain a stable equilibrium (a constant temperature).
But when the virus or bacteria enters, our body's immune system reacts by raising the temperature in order to kill off or make an unsuitable environment for the bacteria/virus.
That is why when a kid (or anyone) gets a fever, it is a sign that something is wrong and the immune system is trying to correct the problem.