Historically, infection control can, we believe, be divided into three eras, each lasting about a half century. We wonder whether we are now seeing the beginning of a fourth.

The first era, which we call the nascent period, began roughly in the middle of the last century. It arose from the discoveries of Ignaz Semmelweis and Florence Nightingale. The benefits of each of their contributions on hospital mortality were so spectacular that they would qualify for the “lead ball” award. (Del Gurchio quoted Lloyd MacLean as saying, “If you hold a lead ball out of the window and when you let it go it goes up, you do not need a statistician to tell you it was a significant event.” Hence, the “lead ball” award.)

The second era would be the aseptic period. It dates from the acceptance of the findings of Pasteur, Lister, and Koch. Their concepts achieved general acceptance, after a hard fight, at the beginning of the 20th century.