This article is about disease-causing organisms. For the Pre-Raphaelite journal entitled The Germ, see The Germ (periodical). For the mathematical notion of an equivalence class of functions, see Germ (mathematics)

Germ is an informal term for a disease-causing organism, particularly bacteria (as in germ warfare). The word is not to be confused with the term from developmental biology (as in wheat germ).

One of the first people to postulate that some diseases were caused by the presence of some kind of very small 'seed' (the original meaning of 'germ') that germinated or multiplied in the body to produce the disease was Ignaz Semmelweis, a Hungarian doctor, practising in an obstetrics ward in the 1840s. He noticed that the death rate of the impoverished women attended by the nurse midwives was many times less than that of the wealthier women attended by the doctors. His observations led him to conclude that it was a matter of cleanliness. The doctors, on their schedules, went directly from the morgue to the obstetrics ward without washing their hands. When he presented his findings to fellow doctors, they discounted his theory, unable to believe in what they could not see. It wasn't until the 1880s and the work of Louis Pasteur and Joseph Lister that the truth of germs finally surfaced and was accepted by the scientific community.

See also

• Virus
• Microbiology
• Hygiene
• germ theory of disease