The World TB Day is celebrated each year on March 24. The day commemorates the discovery of the tuberculosis (TB) bascili, the germs that cause tuberculosis, by Robert Koch in 1882. World TB Day aims to remind the world of this human courage. In 2012 tuberculosis (TB) will affect nearly 9 million people. It will kill 1.4 million of them: That is almost 4,000 every day.