A study shows that the tuberculosis bacterium (Mycobacterium tuberculosis) has been present almost 70,000 years ago when the first modern humans had yet started their world widely migration from their African Homeland.
The origins of the devastating lung infection, tuberculosis, can be tracked down in time longer before than Neolithic people. It first started to domesticate livestock and build the urban centers where tuberculosis could suffuse easily from one person to another.
A comprehensive analysis of the genetics of more than 250 current strains of tuberculosis bacteria from different countries around the world revealed that the infectious agent started with the emergence of Homo sapiens in Africa for more than 70,000 years ago.
By studying the varied genetic variations of Mycobacterium tuberculosis, the researchers were able to illustrate that tuberculosis must have suffused around the world with the first modern humans who came from Africa. This early origin of tuberculosis also shows that the lung infection did not, as formerly thought, transferred to humans from their pet animals or domesticated animals – as farming came in a while.
“We have found that TB was infecting humans before they left Africa around 70,000 year ago. This implies the bacteria have been able to survive in small hunter-gatherer populations,” wrote lead author Iñaki Comas of the Centre for Public Health Research in Valencia.
“At the same time we show that its evolution parallels that of humans and benefits from human demographic explosions,” Dr Comas said. As the human population increased, both during the Neolithic age with the invention of agriculture and later on as a result of the Industrial Revolution, then so also did TB, she said.
The study was published in the online journal Nature Genetics.
This discovery may benefit scientists in creating better methods of blocking new strains that are still resistant to TB drugs. Tuberculosis ranks second on the most infectious disease worldwide with 95 percent of the incidents happening in the middle-income countries, according to the World Health Organization.
