1. Tuberculosis , is a widespread, and in

1. Tuberculosis , is a widespread, and in many cases fatal, infectious disease caused by various strains of mycobacteria. The classic symptoms of active TB infection are a chronic cough with blood-tinged sputum , fever , night sweats , and weight loss. 2. One-third of the world’s population is thought to have been infected with M. tuberculosis , [3] with new infections occurring in about 1% of the population each year. [4] In 2007, an estimated 13. 7 million chronic cases were active globally, [5] while in 2010, an estimated 8. 8 million new cases and 1. 5 million associated deaths occurred, mostly in developing countries. [6] The rate of tuberculosis in different areas varies across the globe; about 80% of the population in many Asian and African countries tests positive in tuberculin tests, while only 5– 10% of the United States population tests positive. 3. Robert Heinrich Herman Koch was a celebrated German physician and pioneering microbiologist. The founder of modern bacteriology , he is known for his role in identifying the specific causative agents of tuberculosis , cholera , and anthrax and for giving experimental support for the concept of infectious disease. During his time as the government advisor with the Imperial Department of Health in Berlin in the 1880 s, Robert Koch became interested in tuberculosis research. [1] At the time, it was widely believed that tuberculosis was an inherited disease. [1] However, Koch was convinced that the disease was caused by a bacterium and was infectious, and tested his four postulates using guinea pigs. [1] Through these experiments, he found that his experiments with tuberculosis satisfied all four of his postulates. [1] In 1882, he published his findings on tuberculosis, in which he reported the causative agent of the disease to be the slow-growing Mycobacterium tuberculosis.