Twenty five years ago, Matthew Kluger showed that because lizards are cold-blooded animals, they are more likely to die when they are infected and cannot move to a warm area to raise their body temperatures.

Fish in interconnected tanks with different water temperatures, prefer lower water temperature when healthy, and choose a higher temperature when infected to reduce their chances of dying. A rise in body temperature after experimental bacterial infection prevents death (1).

Blocking fever with drugs like aspirin increase death rate (2). Aspirin helps you feel better because it blocks pain and reduces swelling, but fever slows the growth of the bacteria and viruses in your body. Bacteria and viruses release pyrogens that enter your body and are attacked by immune cells called macrophages, which release chemicals called interleukins that raise blood levels of prostaglandins, that cause fever. Aspirin inhibits prostaglandins to lower fever, but do not cure disease.

1) Science, Volume 188, p. 166).

2) Science, Volume 193, p. 237.

3) Kluger's Fever: Its biology, evolution, and function (Princeton University Press, 1979.

Checked 8/9/05

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