Leprosy was rare in Europe during the Roman period, yet its prevalence increased dramatically in medieval times. We examined human remains, with paleopathological lesions indicative of leprosy, dated to the 6th-11th century AD, from Central and Eastern Europe and Byzantine Anatolia. Analysis of ancient DNA and bacterial cell wall lipid biomarkers revealed Mycobacterium leprae in skeletal remains from 6th-8th century Northern Italy, 7th-11th century Hungary, 8th-9th century Austria, the Slavic Greater Moravian Empire of the 9th-10th century and 8th-10th century Byzantine samples from Northern Anatolia. These data were analyzed alongside findings published by others. M. leprae is an obligate human pathogen that has undergone an evolutionary bottleneck followed by clonal expansion. Therefore M. leprae genotypes and sub-genotypes give information about the human populations they have infected and their migration. Although data are limited, genotyping demonstrates that historical M. leprae from Byzantine Anatolia, Eastern and Central Europe resembles modern strains in Asia Minor rather than the recently characterized historical strains from North West Europe. The westward migration of peoples from Central Asia in the first millennium may have introduced different M. leprae strains into medieval Europe and certainly would have facilitated the spread of any existing leprosy. The subsequent decline of M. leprae in Europe may be due to increased host resistance. However, molecular evidence of historical leprosy and tuberculosis co-infections suggests that death from tuberculosis in leprosy patients was also a factor.

Centre for Clinical Microbiology Division of Infection and Immunity University College London UK

Centre for Clinical Microbiology Division of Infection and Immunity University College London UK; Department of Anatomy and Anthropology Sackler Medical School Tel Aviv University Israel

Department of Anthropology Hacettepe University Ankara Turkey

Department of Anthropology National Museum Prague Czech Republic

Department of Anthropology Natural History Museum Budapest Hungary

Department of Anthropology Natural History Museum Vienna Austria

Department of Archaeology Foggia University Tivoli Italy

Department of Archaeology Foggia University Tivoli Italy; Anthropological Service of S B A L Rome Italy

Department of Biological Anthropology University of Szeged Hungary

Department of Microbial and Cellular Science Faculty of Health and Medical Sciences University of Surrey Guildford Surrey UK

Department of the Archaeology of Landscape and Archaeobiology Institute of Archaeology Academy of Sciences of the Czech Republic Prague Czech Republic

Institute of Microbiology and Infection School of Biosciences University of Birmingham Edgbaston Birmingham UK

Laboratorio di Bioarcheologia e Osteologia Forense Dipartimento di Scienze Biologiche Geologiche e Ambientali Via Selmi 3 40126 Bologna Italy

Laboratorio di Bioarcheologia e Osteologia Forense Dipartimento di Scienze Biologiche Geologiche e Ambientali Via Selmi 3 40126 Bologna Italy; ADES UMR 7268 CNRS Université de la Méditerranée EFS Université de la Méditerranée CS80011 Bd Pierre Dramard 13344 Marseille Cedex 15 France

Laboratorio di Bioarcheologia e Osteologia Forense Dipartimento di Scienze Biologiche Geologiche e Ambientali Via Selmi 3 40126 Bologna Italy; Centro Fermi Piazza del Viminale 1 00184 Rome Italy

Organic Geochemistry Unit School of Chemistry University of Bristol Bristol UK

School of Archaeology and Earth Institute Belfield University College Dublin Dublin 4 Ireland

University of Szeged Mályva utca 23 H 6771 Szeged Hungary

References provided by Crossref.org

Ancient genomes reveal a high diversity of Mycobacterium leprae in medieval Europe