Ancient origins of TB traced

PARIS, Aug 18, 2005 (United Press International via COMTEX) -- Researchers have considered tuberculosis a relatively recent human affliction, but a French study finds ancient origins of tuberculosis-causing bacteria.

"Our results change the current paradigm of the recent origin of tuberculosis," says Veronique Vincent, senior author of the study and researcher at Institut Pasteur in Paris.

The results may have important future implications for improving diagnosis and treatment of the disease.

Most tuberculosis cases are caused by Mycobacterium tuberculosis and its close relatives. However, some tuberculosis patients from East Africa are infected with unusual bacterial strains that form colonies that appear physically different from M. tuberculosis.

Using genetic data from the different strains, Vincent discovered the ancestors of these bacterial strains were also the progenitors of M. tuberculosis.

The findings, published in PLoS Pathogens, suggest that M. tuberculosis and related strains recently emerged from a much more ancient bacterial species than previously thought, possibly as old as 3 million years.