The skeleton of a young man who died about 1,500 years ago suggests that a particular strain of leprosy was introduced to the UK from Scandinavia, according to new work published in PLoS ONE this week.
Caused by Mycobacterium leprae, the infectious disease leprosy can lead to skin lesions, nerve damage, and muscle weakness. It’s been around in human populations for thousands of years: Some of the oldest known cases come from 2nd century BC Egypt and 1st century Israel and Uzbekistan. The earliest known cases in Europe are from 2nd century Italy, but little is known about the disease's origin in these populations. The European epidemic peaked between the 12th and 14th centuries, and so-called leper colonies were established.
Now, an international team led by Sarah Inskip of Universiteit Leiden have examined 5th or 6th century remains excavated half a century ago from an Anglo-Saxon cemetery located near Great Chesterford, on the boundary between Cambridgeshire and Essex. The skeleton belonged to a young man who died between the ages of 25 and 35 and his grave also included a spearhead, a slender knife, an oval buckle loop near his pelvis, and a bronze shoelace tag above his right ankle. His left arm and most of his facial bones were missing, but he’s otherwise fairly complete.
Some of his bones -- including those in his feet (pictured at the top) -- showed signs of lepromatous leprosy. The team confirmed this using analyses of a lipid biomarker and ancient bacterial DNA. “Not all cases of leprosy can be identified by changes to the skeleton. Some may leave no trace on the bones; others will affect bones in a similar way to other diseases,” University of Southampton’s Sonia Zakrzewski says in a news release. “In these cases the only way to be sure is to use DNA fingerprinting, or other chemical markers characteristic of the leprosy bacillus."
This case of leprosy is the earliest radiocarbon-dated case in Britain. The strain they found in the 1,500-year-old skeleton is the same strain found in earlier graves in Scandinavia. It seems to be ancestral to what’s known as the 3I strain, which was found in later medieval cases from southern Britain and continental Europe. The 3I lineage of Mycobacterium leprae emerged in the Americas later, and it’s still found in some southern states of America in the present day.
Furthermore, isotope analyses of his teeth suggest that the man grew up outside of Britain. Based on the movements of medieval populations in north Western Europe at the time, the team thinks he likely originated from Scandinavia. This means that this strain of leprosy may have been brought to England as early as the 5th century.
Images: 2015 Inskip et al., PLoS ONE (top), University of Southampton (middle)