[Archaeology of tubercle bacilli and tuberculosis]

Accumulated information obtained in the 10 years since the clarification of the whole genome arrangement of tubercle bacilli has enabled us to presume a long history of tubercle bacilli from its first appearance on earth to the present epidemics in the world. It is presumed that tubercle bacilli appeared around 35,000 years ago through horizontal transfer mutation from a kind of environmental mycobacteria that could be tracked back 2,500,000 years, and expanded thereafter by 'bottleneck effects'. These mutated mycobacterial species adapted to humans, appearing in central Africa and then being carried to India-Oceanian and Middle East countries. The oldest human bone tuberculosis in a mummy of 9,000 years ago was found on the east coast of the Mediterranean Sea. Explosive transmission of tuberculosis was presumed to have progressed along with urbanized human life in the world-oldest Mesopotamian culture, followed by spreading to other areas, including East Asia, the Mediterranean region, Russia, and North Europe. The second epidemics, caused by a mutated Beijing family of the modern type, prevailed in central China and Southeast Asian countries, following the marked population growth in this area during the next 1,000 years. The majority of Beijing family strains isolated in Japan and Korea are, however, found to be of the ancient type, differing from the isolates from continental China, which are mainly of the modern type. The results of these studies may cast a new light on the understanding of tuberculosis epidemiology and also clinical medicine.