Discovery of tuberculosis

The disease of tuberculosis, has been known for centuries. Mummies from the Egyptian pre-dynastic era and the Peruvian pre-Columbian era show typical vertebral lesions. Tuberculosis was well known in classical Greece, where it was called phthisis. Hippocrates clearly recognized tuberculosis and understood its clinical presentation.

The oldest evidence for human tuberculosis was found in a Neolithic infant and woman in a 9000-year-old settlement in the Eastern Mediterranean.

In 1720, for the first time, the infectious origin of tuberculosis was conjectured by the English physician Benjamin Marten, in his publication “A new theory of Consumption.”

Both terms consumption and phthisis were used in the 17th and 18th centuries, until in the mid-19th century Johann Lukas Schönlein coined the term “tuberculosis”.

Understanding of the pathogenesis of tuberculosis began with the work of Theophile Laennec at the beginning of the 19th century and was further advanced by the demonstration of the transmissibility of Mycobacterium tuberculosis infection by Jean-Antoine Villemin in 1865.

Mycobacterium tuberculosis, then known as the "tubercle bacillus," was first described on March 24, 1882 by Robert Koch. Using the methylene blue staining recommended by Paul Ehrlich, he identified, isolated and cultivated the bacillus in animal serum. Finally, he reproduced the disease by inoculating the bacillus into laboratory animals.

Mycobacterium tuberculosis is the etiologic agent of tuberculosis in humans. Humans are the only reservoir for the bacterium. Robert Koch presented this extraordinary result to the society of Physiology in Berlin on 24 March 1882. Further molecular analysis of these very first isolates confirmed the identification of M. tuberculosis and indicated that Koch’s isolates belong to the ‘modern’ lineage of M. tuberculosis.

Clemens von Pirquet developed the tuberculin skin test in 1907 and 3 years later used it to demonstrate latent tuberculous infection in asymptomatic children. In the late 19th and early 20th centuries sanatoria developed for the treatment of patients with tuberculosis.
Discovery of tuberculosis

Koch’s Postulates

The germ theory of disease is the idea that a microorganism or ‘germ’ causes an infectious disease. It was first proposed in 1546 by Girolamo Fracastoro. 

Along with Louis Pasteur, Heinrich Robert Koch (8143-1910) used the germ theory in isolating the tuberculosis organisms in 1882 and Vibrio cholerae (1883), the bacterium causes cholera.

His 1882 paper to the Berlin Physiological Society is universally considered by microbiologists as a signature moment in medical science and cornerstone of the germ theory of disease.

He published his discovery of the bacteria that cause tuberculosis, describing his findings that the presence of the tubercle bacillus is strongly correlated with occurrence and development of the disease.

He was the first scientist to devise a series of tests used to assess the germ theory of disease. In 1884, Koch outlined his methods as a series of rules – later to be called Koch’s postulates – which he developed during his studies on the etiology of tuberculosis.

Koch's postulates:
*A particular microbe must be found in all cases of the disease and must not be present in healthy animals or humans
*The microorganism must be isolated from a diseased organism and grown in pure culture.
*The same disease must be produced when microbes from the purge culture are inoculated into healthy susceptible laboratory animals.
*The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.

Koch’s Postulates not only helped to prove the germ theory of disease, but also gave a tremendous boost to the development of microbiology by stressing laboratory culture and identification of microbes.
Koch’s Postulates