Category Archives: bioarchaeology

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.

Autumn Reading

Autumn 2014

So much for my plan to do monthly reading updates. I think quarterly might be more feasible. It seems like the fall has flown by and was not as productive as I would have liked. Isn’t that always the way?

So I’m currently working my way through Cameron’s Anglo-Saxon Medicine and then next up will be the brand new second edition of Mitchell’s A History of the Later Roman Empire AD 284-641.

Books finished:
  • Matilda Holmes, Animals in Saxon and Scandinavian England: Backbones of Economy and Society. Sidestone press, 2014 (reviewed here)
  • Prokopius, The Secret History and Related Texts. Anthony Kaldellis, ed. Hackett, 2010.
  • David Quammen. Ebola: A Natural and Human History of a Deadly Virus. 2014. (excerpted, adapted and updated from his Spillover)
Notable Papers
  • Setzer, T. J. (2014). Malaria detection in the field of paleopathology: A meta-analysis of the state of the art. Acta Tropica, 140, 97–104. doi:10.1016/j.actatropica.2014.08.010 (summarized here)
  • Christina Lee. (2014). Invisible enemies: the role of epidemics in the shaping of historical events in the early medieval period in. Social Dimensions of Medieval Disease and Disability, 1–17.
  • Sallares, R. (2006). Role of environmental changes in the spread of malaria in Europe during the Holocene. Quaternary International, 150(1), 21–27. doi:10.1016/j.quaint.2006.01.005
  • Sallares, R., Bouwman, A., & Anderung, C. (2004). The spread of malaria to Southern Europe in antiquity: new approaches to old problems. Medical History, 48(3), 311–328.
  • Collins, W. E., & Jeffery, G. M. (2007). Plasmodium malariae: Parasite and Disease. Clinical Microbiology Reviews, 20(4), 579–592. doi:10.1128/CMR.00027-07
  • Schreg, Rainer. (2014) “Ecological Approaches in Medieval Rural Archaeology” European Journal of Archaeology, 17 (1), 83-119.
  • Flaherty, E. (2014). Assessing the distribution of social–ecological resilience and risk: Ireland as a case study of the uneven impact of famine. Ecological Complexity, 19, 35–45. doi:10.1016/j.ecocom.2014.04.002
  • SHARPE, W. D., &  Isidore of Seville. (1964). Isidore of Seville: the Medical Writings. An English Translation with an Introduction and Commentary. Transactions of the American Philosophical Society, New Series, 54(2), 1–75.
  • Carter, R., & Mendis, K. N. (2002). Evolutionary and Historical Aspects of the Burden of Malaria. Clinical Microbiology Reviews, 15(4), 564–594. doi:10.1128/CMR.15.4.564-594.2002
I’ve also spent quite a bit of time this autumn reading the pre-print editions of the contributions to Pandemic Disease in the Medieval World: Rethinking the Black Death edited by Monica Green in the inaugural edition of The Medieval Globe, which I’m honored to be a contributor to. Watch this space for more news on this special issue very soon.

The Paleomicrobiology of Malaria Detection

Malaria is arguably one of the most influential infectious diseases in human history. Its been with us as long as we have been human, but as Teddi Setzer shows us in her recent review of detection methods, our abilities to find it in the past leaves a lot to be desired.

The standard method of looking for malaria involves searching for signs of anemia on the skeleton on the hypothesis that the anemia caused by malaria leaves these marks. This is not as clear as it might seem. There have been very few skeletal studies of modern people who have been diagnosed with malaria. There is no medical need; there are much more reliable methods of diagnosing malaria in a living person (or recent cadaver). So, it is unclear how often these lesions form in malaria patients. Other causes of anemia and even scurvy can cause the same or very similar lesions as well.  The number of malarial infections and/or relapses also effect bone changes. Plasmodium falciparium produces a short, virulent disease that may kill before bone changes develop. On the other extreme, a single P. malariae infection can relapse for life, although the anemia is not as severe.  Osteology must be correlated with other information to support the diagnosis. 

Cribra Orbitalia from Jess Beck’s blog Bone Broke

Cribra orbitalia and porotic hyperostosis are the two main indicators sought. Both are caused by bone marrow expansion in an attempt to compensate for the loss of red blood cells. Cribra orbitalia is pitting and extra bone growth in the orbits of the eyes, as seen in the photo.  Porotic hyperostosis causes pitting and thinning of the compact bone ‘shell’ that covers the cranial bones. A  correlation of nutritionally informed osteology with later epidemiology and mosquito incidence in England reviewed in a previous post shows that a convincing case can be made for malaria in ancient remains.

Detection of human genetic traits selected for by malaria such as the Duffy blood group, sickle cell trait, thalassemias, and glucose-6-phosphatase deficiency (G6PD) can with supporting information suggests that the population was once under selection by malaria. Balanced polymorphisms like sickle cell trait can remain in a population for centuries after the selection is gone (by either ecological change or by migration away from the malarious region). While there are some skeletal indicators of some hemoglobinopathies, human ancient DNA analysis would be a more secure method of diagnosis. Care has to be taken to distinguish skeletal changes made by malaria’s hemolytic anemia and the hemoglobinopathy anemias.

Ancient DNA detection of the malaria Plasmodium parasite has been disappointing. To date, only the tropical Plasmodium falciparium, that causes the most severe disease, has been detected by PCR. It is believed that attempts of detect the historically more common Plasmodium vivax have been stymied by the low parasite load in the blood.  The difficulty in finding vivax aDNA is a reminder that pathogens really do need to be in high concentrations within the sample to overcome degradation and be detected by PCR or sequencing technology. As far as I know, there have not been attempts to detect the other three human malarial parasites– Plasmodium ovale, Plasmodium malariae and Plasmodium knowlesi — by aDNA analysis.

Hemozoin crystals in the liver (Source: KMU Pathology Lab)

Modern medicine is devising an ever expanding array of tests for malaria diagnostics and prognostics. However, most of these tests all require fresh (soft) tissue or blood. Immunological methods have not been applied to malaria in archaeological material yet. The most promising detection method for malaria among the newer diagnostics is the detection of the iron containing waste product of the Plasmodium parasite hemozoin. When the parasite feeds on hemoglobin in the red blood cell, toxic iron waste products are processed into the biocrystal hemozoin and excreted into the tissues. In patients with reoccurring or multiple malaria infections, hemozoin will stain their bone marrow black and can be found in liver, spleen, brain and lungs. It can be detected microscopically (as seen above) or by mass spectrometer. Although some other blood parasites also excrete hemozoin, they can be distinguished from the malarial product. 

Despite the advances in diagnosis for existing malaria patients taking advantage of new methods and technologies, archaeological detection has not enjoyed the same success. Building a case for malaria in the past, must rely on an array of data with knowledge of ecology, vectors, and nutritional status of the population in addition to osteological markers of anemia. Hopefully, the detection of hemozoin will eventually be the key to opening up biological studies of malaria in the past. If hemozoin can identify malaria victims, then perhaps focusing the ancient DNA work on hemozoin positive remains will be more successful breaking through the firewall to malaria’s evolution and historical epidemiology. 

 Source:

Setzer, T. J. (2014). Malaria detection in the field of paleopathology: A meta-analysis of the state of the art. Acta Tropica, 140, 97–104. doi:10.1016/j.actatropica.2014.08.010 (open access early editionfinal edition)

See also Jess Brek “Porotic Hyperostosis and Cribra OrbitaliaBone Broke, March 2014.