Oct. 16 --
WEDNESDAY, Oct. 15 (HealthDay News) -- The earliest known cases of human tuberculosis have been identified in 9,000-year-old bones found in an ancient submerged village off the coast of Israel, proving the disease is 3,000 years older than believed, say British and Israeli researchers.
The bones, thought to be from a mother and baby, had characteristic lesions that indicate tuberculosis (TB), and the presence of the disease was confirmed by DNA analysis. The findings, published in the journal PLoS One, support the theory that bovine TB evolved later than human TB.
"What is fascinating is that the infecting organism is definitely the human strain of tuberculosis, in contrast to the original theory that human TB evolved from bovine TB after animal domestication," study co-leader Dr. Helen Donoghue, of the University College London Centre for Infectious Diseases & International Health, said in a PLoS One news release.
"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," Donoghue said.
She and her colleagues "were also able to show that the DNA of the strain of TB in these skeletons had lost a particular piece of DNA which is characteristic of a common family of strains present in the world today. The fact 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."
The findings provide more information about how TB has evolved over thousands of years and improves understanding of how it may change in the future.
"Examining ancient human remains for the markers of TB is very important, because it helps to aid our understanding of prehistoric tuberculosis and how it evolved. This then helps us improve our understanding of modern TB and how we might develop more effective treatments," study co-leader Dr. Mark Spigelman, also of University College London, said in the news release.
The American Lung Association has more about tuberculosis.
SOURCE: PLoS One, news release, Oct. 14, 2008