But the most dangerous bacteria is Scientifically called as Mycobacterium tuberculosis. It has been around the world for centuries. It has been found in the spines of the mummies. In the year 2007 there were 13.7 million chronic active cases in which 9.3 million were new cases and 1.8 million resulted in deaths. According to research , most of the cases are reported from poorer countries.There have been no vaccines yet that can fully cure it. The disease can lie dormant for years in the respiratory system before being activated.