I spent most of last week battling a cold. One of those awful, end of the semester, got-a-taste-of-freedom-but-now-I’m-bedridden colds. If you’re anything like me, the first sign of illness sends you scrambling trying to recall what your mother said about coping with illness. I always seem to remember my mother explaining fevers to me.
I was shivering under a pile of blankets, influenza-ridden and miserable, suffering from the worst fever I experienced as a child. My mother described a war being waged inside me, self versus virus, and tried to convince me that this crummy feeling might actually be a good thing. Impossible! I spent that day wrapped up a little too tightly, flashing from hot to cold, cold to hot. The next morning, I was achy and exhausted—a war had taken place in there, after all—but miraculously, I felt better. I was amazed that my body’s response to the flu-y invader had contributed to its eradication!
“Fever” occurs when body temperature is elevated above the normal range, and we have long been intrigued by its function in staving off infection. In our own bodies, the brain can trigger the body to heat up when it detects infection. This temperature elevation seems to facilitate the immune system, and the warm temperatures make the internal environment less favorable for infectious agents such as bacteria or parasites attempting to live there (feverish to know more?). Endothermic creatures such as us, which produce and maintain body heat internally via metabolic activity, frequently battle infection with fever. But what about ectotherms?