How the Cows Turned Mad
by Maxime Schwartz
: University of California Press
Two and a half centuries ago, sheep in England started trying to scrape their wool off; in France, to shake uncontrollably. The Brits dubbed their phenomenon scrapie; the French called theirs tremblant. Between then and now, similar conditions in cows and humans were discovered and assigned the group name transmissible spongiform encephalopathies (TSEs): diseases that fill the brain with holes as in a sponge and spread from one organism to another. Their cause eluded researchers until quite recently. SOP since Pasteur sought an invasive bacterium or virus with increasingly powerful tools, which TSE agents eluded. Eventually, evidence pointed to a genetic cause involving transformation of a normal into a deviant gene by another deviant gene introduced orally into the affected organism. You had to eat something from a sick organism to become sick, and once that became popular knowledge after the concurrence of human and bovine TSE cases in England in the 1990s, there was a panic. That reaction seems unjustified; according to Schwartz, TSEs will continue to be a very minor cause of human death. Meanwhile, there may be much to learn from TSE research about such symptomatically similar illnesses as Alzheimer's disease. Writing with immense concentration and clarity, French molecular biologist Schwartz makes the long hunt for the unexpected culprit gene utterly engrossing.