Evidence has been discovered off the coast off Haifa, Israel, showing that human tuberculosis existed as long as 9,000 years ago. Traces of the disease have been found in ancient buried bones.
The human strain of the virus was originally thought to be 6,000 years old, but now researchers at University College London and Tel Aviv University have proved it is much older and in fact existed before bovine TB - despite previous beliefs.
The discovery was made when professor Israel Hershkovitz of Tel Aviv University examined the skeletal remains - unearthed at Alit-Yam, a 9,000 year-old pre-pottery Neolithic village. The bones contained lesions that are affiliated with TB.
An international multi-disciplinary team was headed by Dr Helen Donoghue and Dr Mark Spigelman, of the UCL Centre for Infectious Diseases & International Health. Bone analysis was carried out using special techniques to unveil DNA and cell wall lipids from mycobacterium tuberculosis - the main factor in human TB.
Earlier research into finding the origins of the disease used computer analysis to go backwards by studying the rate of change of the DNA. On this occasion, Dr Donoghue said, “We have gone directly to 9,000 year old human bones and had a look.”
Luckily the DNA in the discovered bones were in a good state of preservation, thus allowing for the appropriate tests to be performed. Dr Donoghue further notes that the study,
“gives us a marker in real time so we can start to have a better picture of how TB is changing. We need to understand how it’s changing, what causes it to change, because it’s still changing.”
The discovery has disproved the belief that TB existed in animals before humans. Dr Donoghue goes on to say,
“This gives us the best evidence yet that in a community with domesticated animals but before dairying, the infecting strain was actually the human pathogen. The presence of large numbers of animal bones shows that animals were an important food source, and this probably led to an increase in the human population that helped the TB to be maintained and spread.”
Also discovered through the findings was that certain traits of TB have actually changed in 9,000 years - a piece of DNA common to today’s TB was missing from the skeleton. Dr Donoghue comments,
“The fact that this deletion had occurred 9,000 years ago gives us a much better idea of the rate of change of the bacterium over time, and indicates an extremely long association with humans.”
Many people think that TB is all but eradicated. However aggressive drug resistant forms of the disease are vast in Russian jails and throughout China. In fact two billion people world wide are thought to be infected - that is a third of the world population. Of those infected however, only 10 per cent will develop an illness through it. Famous people throughout history who have been infected with TB include John Keats, Franz Kafka and members of the Brönte family.
It is even closer to home than us Brits may realise. The rate of infection in the UK is on a similar par with that of Uganda - one of the most under developed countries in the world.
Dr Donoghue finishes saying, “We think that you need to understand how TB evolved and originated and our relationship with the bacteria. You need to understand how it started to understand how we got to where we are. And hopefully it will throw light onto where we’re going in the future.”
