Mycobacterium ulcerans persistence at a village water source of Buruli ulcer patients

Buruli ulcer (BU), a neglected tropical disease of the skin and subcutaneous tissue, is caused by Mycobacterium ulcerans and is the third most common mycobacterial disease after tuberculosis and leprosy. While there is a strong association of the occurrence of the disease with stagnant or slow flowing water bodies, the exact mode of transmission of BU is not clear. M. ulcerans has emerged from the environmental fish pathogen M. marinum by acquisition of a virulence plasmid encoding the enzymes required for the production of the cytotoxic macrolide toxin mycolactone, which is a key factor in the pathogenesis of BU. Comparative genomic studies have further shown extensive pseudogene formation and downsizing of the M. ulcerans genome, indicative for an adaptation to a more stable ecological niche. This has raised the question whether this pathogen is still present in water-associated environmental reservoirs. Here we show persistence of M. ulcerans specific DNA sequences over a period of more than two years at a water contact location of BU patients in an endemic village of Cameroon. At defined positions in a shallow water hole used by the villagers for washing and bathing, detritus remained consistently positive for M. ulcerans DNA. The observed mean real-time PCR Ct difference of 1.45 between the insertion sequences IS2606 and IS2404 indicated that lineage 3 M. ulcerans, which cause human disease, persisted in this environment after successful treatment of all local patients. Underwater decaying organic matter may therefore represent a reservoir of M. ulcerans for direct infection of skin lesions or vector-associated transmission.

Pile-dwellings of the Neolithic and the Bronze Age in Switzerland. Long-term research and future tasks

Swiss lake-side settlements dating between 4300 and 800 BC were first recognized in the early 19th century and between 1854 and 1880 early research boomed due to the first scientific studies and the artificial lowering of lakes in Western Switzerland. In the 20th century underwater and wetland archaeology experienced an enormous surge not only because of large rescue excavations, due to extensive motorway construction projects but also due to the evolution of modern IT technology in the 1970s. For the first time huge quantities of ancient wooden structures could be dated by dendrochronology. This produced a quantum leap in the 150 years of pile-dwelling research. In 2011, the UNESCO World Heritage Committee recognized the outstanding universal value of these sites. This article presents an overview about Swiss pile-dwellings of the Neolithic and the Bronze Age and the results of two recent diploma works (case study Sutz-Lattrigen Haupstation innen and case study Seedorf Lobsigensee) as examples of research and cooperation between universities and government agencies for cultural heritage management.