Pilgrims spread leprosy across medieval Europe

Leprosy may have hitched a ride across the medieval world via religious pilgrimages.

Researchers in the UK used radiocarbon dating, genotyping and biomolecular analysis to piece together the story of a young man who died at a leprosy hospital during the early 12th century.

Reporting in PLOS Neglected Tropical Diseases, they conclude he was a visitor to the area. And the strain of leprosy found in the skeleton’s remains, which persists today, was probably contracted elsewhere in the world, pointing to a potential relationship between leprosy transmission and medieval pilgrimage.

Leprosy is caused by the bacteria Mycobacterium leprae or Mycobacterium lepromatosis. Symptoms can include skin lesions, blindness and loss of the ability to feel pain. Today’s infections are curable with multiple drug therapy, but before antibiotics, sufferers were relegated to colonies and hospitals.

One of these hospitals was the St Mary Magdalen hospital site near Winchester in the UK. Some 86% of remains excavated from the hospital’s cemetery show symptoms consistent with leprosy, which reached epidemic levels in the Middle Ages.

The man studied by researchers led by Simon Roffey and Katie Tucker from the University of Winchester and the University of Surrey’s Michael Taylor was buried alongside a scallop shell with a hole pierced through it – the symbol of a pilgrim who made the journey to the shrine of St James in Santiago de Compostela in Spain.

“Throughout the medieval period the act of pilgrimage was viewed as a particularly efficacious spiritual and devotional practice and many of the medieval saints’ shrines were associated with miraculous cures and healing, including leprosy,” the researchers write.

By studying facial structure and tooth enamel, the team ascertained the male wasn’t local to the area, but the researchers say this isn’t surprising – Winchester, home to many relics and churches, also had spiritual importance for pilgrims.

Still, it’s unclear at what point during or following his pilgrimage he contracted the disease. But the man is also thought to have had some standing in the community at the time of his burial. His diet appears to have been very protein-heavy, which richer folk could afford, and his grave was left intact, while many of his neighbours had been moved.