Tuberculosis is a disease that usually affects the respiratory system, but it can also affect the gastro-intestinal system, the central nervous system, lymphatic cells, bones, joints and even the skin. Its typical symptoms are a chronic cough with a blood-tinged sputum, weight loss and high fever. The impact of tuberculosis on the modern world is still incredibly significant, considering that one-third of the world’s population has been infected and that every second one more person becomes infected. In 2004 alone, 1.6 million people died from this disease.
Throughout the history of tuberculosis, when diagnostic techniques were not as advanced as today, the numbers of infected individuals must have been even more staggering, and the infection rate much higher. Even though this disease was so widespread and feared, no one before the 1800s had carried out any specific study of the causes and the characteristics of tuberculosis.
Robert Koch, sometimes considered the father of microbiology (though most often the title goes to Anton van Leeuwenhoek), was the first one to understand that the tuberculosis cause was microbiological in nature and he was the first to scientifically prove his conclusions. In fact, in 1882, Koch gave a lecture on the methodology he used to isolate and observe bacteria, and most significantly the bacterium that causes tuberculosis, leaving a whole audience of illustrious doctors and academicians speechless. Many of the people that were present at the lecture described it as one of the most, if not “the” most, important medical experience in which they had ever participated.
Beside his trusty microscope, which was indubitably one of the most important tools Koch used during his studies, success was also due to the techniques for the isolation and the identification of bacteria that he developed himself. Indeed, it was during Koch’s time that the germ theory of disease was beginning to gain importance and a number of scientists were eager to search for the microorganisms responsible for diseases; this led to the development of a number of methodologies for the isolation and identification of those microorganisms. Koch perfected many of those methodologies.