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Genotyping reveals little change in leprosy over last 1,000 years
Through examination of a medieval skeleton excavated from a leprosy hospital cemetery in Winchester, UK, researchers found no significant change in the M. leprae genome since the late 11th century, which could explain how disease transmission rates declined as resistance grew, according to research published in PLoS Neglected Tropical Diseases.
“This leprosy hospital… is remarkable for the high number of burials displaying skeletal lesions characteristic of leprosy (86%) and the state of preservation of biomolecular markers of the disease, including mycolipids and DNA,” Simon Roffey, PhD, from the department of archaeology at the University of Winchester, UK, and colleagues wrote. “This has previously allowed detailed genotyping by conventional PCR and for next generation sequencing (NGS)… [to reveal] a remarkably high level of genomic conservation in the leprosy bacillus over the last one thousand years.”
Researchers performed extensive tests on a skeleton excavated from the medieval hospital of St Mary Magdalen to better understand the genetic origins of leprosy, a bacterial infection caused by Mycobacterium leprae or Mycobacterium lepromatosis that has afflicted humans for thousands of years and was once an epidemic in Europe. In this multidisciplinary study, Roffey and colleagues used genotyping, radiocarbon dating, biomolecular analysis, osteology, strontium and oxygen isotopic analyses to examine the remains.
Using radiocarbon dating showed that the individual, believed to be a religious, male pilgrim of mostly non-UK heritage aged roughly 18 to 25 years at the time of death, was buried in the late 11th – early 12th century when pilgrimages were at their peak in Europe. Genotyping revealed that the M. leprae strain tested from the skeleton place it in the 2F lineage, a strain typically associated with cases from South-Central and Western Asia. The researchers determined that the M. leprae genome uncovered from the remains is not significantly different compared with the disease today, which can explain the decline in transmission as resistance developed among humans. It is unclear at what point during or after his pilgrimage he contracted leprosy, but this project allowed the investigators to study the strain of leprosy and compare it with the disease we see today.
“Further ancient genome analysis linked to population genetics can potentially provide important additional information on the genetic origin,” Roffey and colleagues wrote. “But overall these findings confirm the benefits of a multidisciplinary approach, which allows investigation of the wider relationship between leprosy, medieval pilgrimage and M. leprae transmission.” – by Savannah Demko
Disclosure: Roffey reports no relevant financial disclosures.