Mycolic acids and ancient DNA confirm an osteological diagnosis of tuberculosis

Setting: The underlying trends in the past epidemiology of tuberculosis (TB ) are obscure, requiring recourse to the archaeological record. It would th erefore be of value to develop methods for reliable TB diagnosis in ancient populations. Objective: To test the capability of two biomarkers, Mycobacterium tubercul osis complex mycolic acids and a DNA target (IS6110), for confirming an ost eological diagnosis of TB in medieval individuals, based on the presence of Pott's disease and/or rib lesions. Design: Osteological examination of three archaeological individuals (Medie val: similar to 1000 years old) revealed a Pott's disease case, one with no changes consistent with TB and one with rib lesions. Rib samples from thes e individuals were examined for the presence of Mycobacterium tuberculosis complex mycolic acids and mycobacterial DNA. Results: Mycobacterium tuberculosis complex mycolic acids and the DNA targe t were detected in the Pott's disease case, whilst mycolic acids (insuffici ent for confirmation) alone were detected in the rib lesion case. Conclusions: Biomarkers provide a sensitive tool to detect ancient TB. Myco bacterium tuberculosis DNA is not distributed homogeneously, making multipl e sampling essential. Mycolic acids seem more reliable for ancient TB diagn osis than IS6110. The demonstrated stability of mycolic acids show that the y may be of value in tracing the palaeoepidemiology of tuberculosis back in to antiquity. (C) 2001 Harcourt Publishers Ltd.