The earliest known cases of human tuberculosis have been found in millennia-old bones that were buried off the coast of Haifa, Israel.

New research by scientists from institutions including University College London (UCL) and Tel Aviv University shows that the infection is 3,000 years older than was previously imagined and that TB in people evolved before bovine TB.

Professor Israel Hershkovitz of Tel Aviv University noticed lesions that are a sign of TB in the bones of skeletons discovered at Alit-Yam, a 9,000 year-old pre-pottery Neolithic village.

Dr Helen Donoghue and Dr Mark Spigelman, of the UCL Centre for Infectious Diseases & International Health, led an international collaborative team through analysing the bones using scientific techniques to reveal DNA and cell wall lipids from mycobacterium tuberculosis, the principal agent of human TB.

Previous studies of the origins of the infection have used computer analysis to work backward by looking at the rate of change of the DNA. This time, Dr Donoghue said, "We have gone directly to 9,000 year old human bones and had a look."

The DNA in the excavated bones was sufficiently well-preserved for molecular typing to be carried out and the analysis of the bacterial cell wall lipids by high performance liquid chromatography provided evidence of tuberculosis.

The study, Dr Donoghue said, "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."

This research disproves the previous notion that human TB emerged after bovine TB with animal domestication. "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," Dr Donoghue added.

The findings also tell about the evolution of the bacterium; skeletons lost a particular piece of DNA characteristic of today's TB strains. "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," said Dr Donoghue.

TB is believed to infect about two billion people, or a third of humanity, though it is ten per cent of those infected that fall ill. Literature is scattered with victims of TB, from members of the Brönte clan, to Franz Kafka and John Keats. Drug resistant strains of the infection are rampant in Russian jails and throughout China.

But TB is closer in time and space than we often imagine: people in London are infected at the same rate as people in Uganda, which is among the least developed countries in the world.

Dr Donoghue told The Times: "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."

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