Thursday, August 30, 2012

Survival of the Sickest: The Surprising Connections Between Disease and Longevity by Sharon Moalem

This book explores the relationships between human disease and evolutionary advantage. For example, some people (including many of Western European descent) have a genetic disorder which causes them to retain too much iron, which then accumulates in organs such as the liver and the brain. While this disorder can lead to death if not treated (the most effective treatment is bloodletting), it probably offered a better chance of survival against the plague (because the form in which the iron is present in the bloodstream is inaccessible to bacteria). The book also looks at the relative virulence of disease in relation to forms of transmission (a cold, for example, will probably not be deadly because you spread it best if you can be walking around and interacting with others, while cholera, which often spreads through contaminated water, doesn't require its human host to be mobile). I found this book thoughtful and fascinating, and I agreed with its conclusions: rather than just trying to eliminate bacteria and viruses, we should be trying to make them evolve in ways that are helpful rather than harmful to human survival.

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