Category Archives: aDNA

A Migration Age Anglo-Saxon Leper

Paleomicrobiology and isotopic analysis has the ability to completely change what we know of past infectious diseases. A study published this month on a fifth century Anglo-Saxon skeleton is one of the most complete I have read.

Lesions on skeletons found at Great Chesterfield in Essex, England, suggested possible leprosy. To confirm this diagnosis, they chose one skeleton that is nearly complete and in good shape for further analysis.

Grave GC86 from Great Chesterford, excavated in a rescue archaeology operation in 1953-4.
Grave GC86 from Great Chesterford, excavated in a rescue archaeology operation in 1953-4. (Inskip et al, 2015)

The skeleton (GC96) shown to the right is of a 25 to 35-year-old male buried in modestly furnished grave in an area of the cemetery with other visibly disabled people. Radiocarbon dating places these remains at AD 415-545, and thus Migration Age for the Anglo-Saxons. The Great Chesterford cemetery is located roughly in an approximate border area between the kingdom of the East Saxons and East Angles at the site of a ford of the River Cam (or Granta) downriver from Cambridge. He was buried with a slender knife secured by a belt with an oval buckle. Over his left shoulder, a spear and a conical ferrule were found.  Lesions consistent with lepromatous leprosy were found on the lower legs with extensive remodeling of the right foot. A bronze shoelace tag found near the right foot suggests the diseased foot covered with a shoe.  Given the lesions found on the foot and lower legs, the ferrule may have capped a walking staff. His facial bones were missing losing a common, distinctive site of leprosy lesions. The disorganized and rough appearance of new bone growth suggest that the lesion was active at the time of death.

Profile of the mycolic acids extracted from the indicated bones.
Profile of the mycolic acids extracted from the indicated bones. (Inskip et al, 2015)

Selections of bone were taken and powdered to extract aDNA and for lipid analysis. Mycobacterium species that cause leprosy and tuberculosis have distinctive lipid profiles that have been successfully extracted and identified by archaeological remains in the past. Their analysis of lipids from the bones confirmed the presence of Mycobacterium leprae and excluded the presence of Mycobacterium tuberculosis.  The aDNA analysis confirmed identified the presence of Mycobacterium leprae strain 3I-1, that has been previously found in later medieval England, Denmark and Sweden. Inskip et al (2015) suggest a possible Scandinavian origin for the strain.  The VNTR analysis used to produce ‘genetic fingerprints’ shows that this strain of M. leprae is unique among other ancient isolates and should be useful in the comparative analysis of other early remains. Other remains in the same cemetery have similar lesions and will be investigated in the future.

Isotopic analysis of his tooth enamel provide an indication of childhood location and adult nutrition. Carbon analysis showed a diet of primarily C3 plants, consistent with southern Britain. Analysis of oxygen and strontium isotopes suggest he did not spend his childhood in the area of Great Chesterford.

The combination of the two isotopes gives his best probable origin to be between north-central France and the north-central Germany, in other words, the region of the Anglo-Saxon homeland. A continental origin coupled with the dating range between 415 and 545 suggests that he was part of the migration of the peoples who later called themselves Anglo-Saxons. He was likely no more Scandinavian than any of the other migration era ‘English’. This is further supported by a relatively high level of leprosy (by osteological analysis) in medieval city of Schleswig, the very area where the Angles are most specifically located. Further analysis of migration era remains should refine the origins of this strain of leprosy and determine its frequency.

Reference:

Inskip, S. A., Taylor, G. M., Zakrzewski, S. R., Mays, S. A., Pike, A. W. G., Llewellyn, G., et al. (2015). Osteological, Biomolecular and Geochemical Examination of an Early Anglo-Saxon Case of Lepromatous Leprosy. PLoS ONE, 10(5), e0124282. doi:10.1371/journal.pone.0124282.s001

Kristina Killgrove, 14 May 2015 “Earliest Case of Leprosy in Britain reveals Scandinavian Origins of the Disease”, Forbes.com

SIMON MAYS, SONIA R. ZAKRZEWSKI, SARAH A. INSKIP, STEPHANIE WRIGHT and JOANNA R. SOFAER. (2015) Anglo-Saxon concepts of dis/ability: placing disease at Great Chesterford in its wider context. Poster at The 84th Annual Meeting of the American Association of Physical Anthropologists.

Contours of the Black Death Cemetery at Charterhouse Square, London

Excavations for the Crossrail Extension project discovered the second major Black Death cemetery in London in 2013. This week the first peer-reviewed publication of findings from the site appeared (in press).  As a rescue excavation in the midst of a construction project, the site had to be quickly surveyed for the extent of the cemetery and this is what is contained in this publication.

This site is part of 13 acres leased by Sir Walter de Mauny from St Bartholomew’s Priory for an emergency cemetery for plague victims in 1349 AD.  The site has been used for a variety of purposes over the centuries and currently is a four acre green space called Charterhouse square. The site is graphically displayed below with the locations of later structures.

Crossrails site, London
Crossrails site in Charterhouse Square, London (Dick et al., 2015)

The initial discovery came in a shaft just to the southwest of the Charterhouse Square. There they found three layers of graves with a total of 25 bodies lacking signs of trauma and with pottery shards from 1270-1350 AD. Subsequent radiocarbon dating and aDNA analysis confirmed that they were victims of the Black Death.

The surveys conducted over just two days were able to outline the broad contours of features at the site. These included a 15th century building, a priory kitchen, a probable World War II submerged emergency water tank, and a possible ditch and bank along the cemetery that is mentioned in descriptions. They believe that a disturbed area in the southwest corner represents about 200 individual graves, although only excavation can confirm these graves. They concluded that their ability to detect medieval objects in such an intensely used urban area suggests these methods are a good option for similar future situations.

The scans also revealed some surprises. There are not as many graves as descriptions suggest should have been there, though bodies may be more dense that suggested by the scans. They also did not find any large pits of  stacked bodies. This indicates that even during the height of the Black Death, many people were still buried in individual graves. Graves were found in three phases with layers of clay-rich earth in between perhaps in an attempt to seal the graves. These scans should allow them to target future excavations to areas with a high probability of dense graves.

Reference:

Dick, H. C., Pringle, J. K., Sloane, B., Carver, J., Haffenden, A., Stephen Porter, H. A., et al. (2015). Detection and characterisation of Black Death burials by multi-proxy geophysical methods. Journal of Archaeological Science, 1–50. doi:10.1016/j.jas.2015.04.010 [In press, accepted manuscript]

Expanding the Historical Plague Paradigm

When the first complete genomic sequence of Yersinia pestis was published on October 4, 2001 the world was naturally focused elsewhere, on anthrax bioterrorism — the Amerithrax incident was then in its second week– and the September 11 attacks were just over three weeks old. As the world redeveloped bioterrorism assessments and plans, plague was placed on lists along with anthrax, smallpox and yes, ebola as agents of national security concern and response.  Although plague produced more annual cases than most agents on the category A bioterrorism list, it was placed on the list primarily based on its historical reputation and past attempts to weaponize it (also based on its reputation). Yet, in 2001 there was a fierce debate ranging among historians and others on whether Yersinia pestis was the agent of the Black Death at all.

It would take another ten years before genomics would revolutionize our understanding of the historical plague. On October 12, 2011 the first draft sequence of an ancient plague genome was published. Finally, adding to the detection of Yersinia pestis DNA tests previously done on remains, the draft sequence isolated from the East Smithfield Black Death cemetery in London solidified consensus that Yersinia pestis is the agent of the Black Death pandemic.  Meanwhile, the phylogenetic tree of Yersinia pestis had been constructed based on the genetic sequence of isolates from all over the globe. Ancient and modern Yersinia pestis genomes were opening a new window into the history of the species.

As fundamental as genomic analysis is to the new understanding of historical plague, it is a skeleton of data that is open to many different historical interpretations. Science can’t adequately explain the historic plague epidemics alone; it takes historical context. In the inaugural double issue of The Medieval Globe,  Pandemic Disease in the Medieval World: Rethinking the Black Death (open access) begins this process. The eleven articles in this issue take the genetic identification of Yersinia pestis  as the agent of the Black Death as foundational and integrate modern biological and epidemiological information into a new global Old World assessment of the history of the Black Death and subsequent epidemics. Each of these articles lays the groundwork for future interdisciplinary work between historians, anthropologists, biologists, epidemiologists and others.

In my own contribution to this issue, “The Black Death and the Future of the Plague” I discuss why plague is still important in the modern world and for our future. Plague has played an integral role in the development of the re-emerging infectious diseases paradigm and is an agent of biosecurity concern. I review the current state of plague around the world, what we have learned about plague epidemiology and transmission, and how it can be applied to historic epidemics. I also make my case for why the study of the entire history of plague is uniquely important and why the sciences and humanities must move forward together.  I hope we can engage in a discussion on these issues here in the comments section, on twitter or by email.

My own interest and awareness of the issues surrounding the study of the plague was transformed when I had the great fortune to be invited by Monica Green to participate in a session at the American Historical Association annual meeting in New Orleans, January 2013. The group of plague scholars gathered there has largely remained in contact and expanded our network into an informal working group that has enriched all of our scholarship.  No one can become fully conversant with all of the disciplines involved in the study of even one epidemic, much less the entire history of the plague.  Working in disciplinary seclusion will not produce a satisfying paradigm or widespread consensus. It takes work, patience and some tolerance of how other disciplines work, but I have found it to always be worth it. I hope you will agree.

Some references for the milestones mentioned:

Parkhill, J., Wren, B. W., Thomson, N. R., Titball, R. W., Holden, M. T., Prentice, M. B., et al. (2001). Genome sequence of Yersinia pestis, the causative agent of plague. Nature, 413(6855), 523–527. doi:10.1038/35097083

Morelli, G., Song, Y., Mazzoni, C. J., Eppinger, M., Roumagnac, P., Wagner, D. M., et al. (2010). Yersinia pestis genome sequencing identifies patterns of global phylogenetic diversity. Nature Genetics, 1–20. doi:10.1038/ng.705

Little, L. K. (2011). Plague Historians in Lab Coats. Past & Present, 213(1), 267–290. doi:10.1093/pastj/gtr014

Bos, K. I., Schuenemann, V. J., Golding, G. B., Burbano, H. A., Waglechner, N., Coombes, B. K., et al. (2011). A draft genome of Yersinia pestis from victims of the Black Death. Nature, 1–5. doi:10.1038/nature10549

Pandemic Disease in the Medieval World: Rethinking the Black Death. Edited by Monica Green. The Medieval Globe, 1 (1), 2014.