Robert Koch discovered the bacterium responsible for tuberculosis.

On 24 March 1882, Robert Koch announced his discovery of Mycobacterium tuberculosis, the bacterium that causes tuberculosis, a date now observed as World TB Day.

It marked a monumental turning point in medical history, as TB had been responsible for one in seven deaths in Europe and the Americas and was widely believed to be hereditary rather than infectious.

This breakthrough transformed medical science by proving TB was an infectious disease.

His work also led to Koch's postulates, establishing how microbes cause diseases, a principle still vital today.
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