Why do we get fevers?

Twenty five years ago, Matthew Kluger showed that cold-blooded animals such as lizards are more likely to die when they are infected if they cannot move to a warm area to raise their body temperatures. More recent studies show that fish in interconnected tanks with different water temperatures, prefer lower water temperature when healthy, and choose a higher temperature when infected. A rise in body temperature after experimental bacterial infection helped to prevent death (Science, Volume 188, 2003).

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, and helps you feel better because it blocks pain and reduces swelling. But taking aspirin or other medications to lower a fever does not cure the disease that caused it.

May 1, 2006

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