Germ theory
From RationalWiki
Germ theory is the theory that microscopic organisms (bacteria, viruses, or certain protozoa, as well as a few very weird things like free-living cancer cells) cause infectious diseases. Confirmed in the 19th century by French biologist Louis Pasteur, germ theory is one of the most well-established principles in medicine and epidemiology, as well as a cornerstone for public sanitation policy. Incredibly, despite a mountain of evidence that would make evolution look like a statistical glitch, it still has its deniers, many of whom portray Pasteur as a shill for the French wine industry or an outright fraud. Such people, curiously, will seldom offer to take an injection of HIV or a shot glass of salmonella to prove their thesis.
[edit] Basics
Germ theory states that microorganisms can and often do cause disease. The often referred-to Koch's postulates are one algorithm that describes the relationship between a microorganism and a disease, but they are not considered "gospel"
[edit] History
Humans have explored the causes of disease transmission since written records exit. Herodotus discussed the origins of smallpox, Hippocrates studied many infectious diseases, and described them quite accurately.
Early theories focused on miasmas, humoral imbalance, and other speculative ideas. It wasn't until the 18th and 19th centuries that actual progress was made.
In the 19th century Ignaz Semmelweis made seminal observations on childbed fever, noting that in situations where doctors washed their hands between procedures, the incident of sepsis among delivering mothers dropped off drastically. Other researchers, such as Billroth (discovery of streptococci in pus), Pasteur (discovery of strep in the blood of a septic woman), and Lister (pioneer of antisepsis in surgery) cemented the germ theory of disease as one of the foundations of modern science.
[edit] Modern Era
Before the onset of the AIDS epidemic, it was thought that infectious diseases were on their way to being wiped out. The new, modern area of infections disease has continued to grow in success and sophistication, especially with the study of genetics and genomics. Despite this, a fringe denialst movement has cropped up in recent years, and many forms of alternative medicine either ignore or outright deny germ theory.
