Medieval skeleton gives clues to the genetic origins of leprosy
The skeleton of a medieval leprosy victim excavated from one of Britain's earliest known hospitals is shedding light on the genetic origins of the disfiguring disease leprosy.Leprosy is a bacterial infection which has afflicted humans for thousands of years - reaching epidemic levels during the Middle Ages - and is still affecting people today. However, the genetic origins of the disease are not well understood.
Researchers from the universities of Winchester and Surrey investigated the strain of leprosy found in St Mary Magdalen, a leprosy hospital cemetery in Winchester, Hampshire, founded in the mid to late Eleventh Century, probably as a response to the sudden spread of leprosy in England. Extensive tests were carried out on a skeleton excavated from the cemetery, including genotyping, radiocarbon dating and biomolecular analysis.
Dr Simon Roffey, Reader in Archaeology at the University of Winchester; Katie Tucker, Postdoctoral Research Fellow at the University of Winchester, and Dr Mike Taylor, a bioarchaeologist at the University of Surrey, and colleagues, discovered that the genome of Mycobacterium leprae, the bacterium which causes leprosy, has not significantly changed since the disease peaked in medieval Europe. This finding could explain why there was a decline in the transmission of leprosy, as resistance to the bacterium may have developed.
Radiocarbon dating shows that the remains were buried during the late Eleventh to early Twelfth Century. The research team believes that the medieval leprosy victim was a religious pilgrim of means, possibly from overseas as he was of mostly non-UK heritage. In addition to this single skeleton which was analysed in great detail, the research team found 86 per cent of all remains they studied at the burial site showed skeletal lesions indicating leprosy, the largest percentage recorded in Britain.
Genotyping the M. leprae strain sampled from the skeleton identified it as a strain commonly found today in cases from South-Central and Western Asia. Whilst other M. leprae strains examined at the Winchester leprosy cemetery were also of the same type, the strain sampled from the skeleton was found to be genetically distinct from these other cases.
However, although the research team identified the strain of leprosy the pilgrim contracted, it remains unclear whether he contracted leprosy before, during or after his pilgrimage.
The authors say: "Our findings confirm the benefits of a multidisciplinary approach which allows investigation of the wider relationship between leprosy, medieval pilgrimage and M.leprae transmission."
The University of Winchester's Department of Archaeology has been extensively researching St Mary Magdalen since 2007, led by Dr Roffey and Dr Phil Marter, Senior Lecturer in Applied Archaeological Techniques, and the site is used as a training excavation for undergraduate and postgraduate archaeology students studying at the University.
Dr Roffey says: "Work at the site has focused on the buildings, burials and artefacts with the aim of studying the history and development of the former medieval leprosy hospital. Now our work is feeding into the scientific origins of leprosy to give a greater understanding of the disease."
The results of the research are published in the journal PLOS Neglected Tropical Diseases HERE.