# What causes infectious disease

- kind: problem
- status: solved (evidence tier V3)
- year: 1546

**Statement.** Are diseases caused by bad air, imbalance of humors, or living microorganisms?

Semmelweis showed in 1847 that handwashing cut deaths in childbirth, and he was ignored. Pasteur and Koch established that specific microbes cause specific diseases, and Koch's postulates set the standard of proof. Sanitation, antisepsis and vaccines followed.

*Evidence tier V3 is the import default for a result the curation records as settled in the published record. No formal proof or certificate is attached to this page yet.*

Closed 1860s–1880s, Louis Pasteur and Robert Koch.

## Sources

- [Wikipedia: Germ theory of disease](https://en.wikipedia.org/wiki/Germ_theory_of_disease)

[Infectious disease](/wiki/Space:infectious-disease.md) · [Medicine](/wiki/Continent:medicine.md)

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