Leprosy in medieval Denmark: Exploring life histories through a multi-tissue and multi-isotopic approach.

OBJECTIVES: By focusing on two Danish leprosaria (Naestved and Odense; 13th-16th c. CE) and using diet and origin as proxies, we follow a multi-isotopic approach to reconstruct life histories of patients and investigate how leprosy affected both institutionalized individuals and the medieval Danish community as a whole. MATERIALS AND METHODS: We combine archaeology, historical sources, biological anthropology, isotopic analyses (δ13 C, δ15 N, δ34 S, 87 Sr/86 Sr) and radiocarbon dating, and further analyze bones with different turnover rates (ribs and long bones). RESULTS: The δ13 C, δ15 N and δ34 S results indicate a C3 terrestrial diet with small contributions of marine protein for leprosy patients and individuals from other medieval Danish sites. A similar diet is seen through time, between males and females, and patients with and without changes on facial bones. The isotopic comparison between ribs and long bones reveals no significant dietary change. The δ34 S and 87 Sr/86 Sr results suggest that patients were local to the regions of the leprosaria. Moreover, the radiocarbon dates show a mere 50% agreement with the arm position dating method used in Denmark. CONCLUSIONS: A local origin for the leprosy patients is in line with historical evidence, unlike the small dietary contribution of marine protein. Although only 10% of the analyzed individuals have rib/long bone offsets that undoubtedly show a dietary shift, the data appear to reveal a pattern for 25 individuals (out of 50), with elevated δ13 C and/or δ15 N values in the ribs compared to the long bones, which points toward a communal type of diet and reveals organizational aspects of the institution.

The association between skeletal lesions and tuberculosis in a pre-antibiotic South African sample.

OBJECTIVE: This study assessed the sensitivity and specificity of skeletal lesions to accurately diagnose TB in a pre-antibiotic South African skeletal sample. MATERIALS: A total of 435 skeletons of individuals who died before 1950 from the Raymond A. Dart Collection of Human Skeletons. 176 died of TB, 109 died of other pulmonary diseases, and 150 died of other causes. METHODS: The presence / absence of 23 skeletal lesions were assessed for differences in frequency between groups. Sensitivities and specificities were calculated and compared to Dangvard Pedersen et al. (2019). RESULTS: Lesions on the ventral surface of thoracic and lumbar vertebral bodies were observed significantly more often in TB and pulmonary cases than in other cause of death group and yielded a 55% probability of a true TB diagnosis, if observed. An association between skeletal lesions and TB was found for rib and vertebral lesions. CONCLUSIONS: The results suggest that even when not documented to have died of TB, TB-related changes are observed in many individuals in a South African skeletal sample, indicating that they may have been infected with the disease. SIGNIFICANCE: The study provides information that can assist palaeopathologists in making inferences about the prevalence of TB in past populations. LIMITATIONS: Sample sizes were small, and the inclusion of a pulmonary disease group may have confounded the results. SUGGESTIONS FOR FURTHER RESEARCH: The selection of a control group without any possible contact with TB may improve the results and should be investigated.

Impact of urbanization on tuberculosis and leprosy prevalence in medieval Denmark.

The consequences of urbanization, such as increased exposure to pathogens, have long been considered detrimental to human health. During the first half of the Danish medieval period, towns were established and throughout the period population increased. The following study analyzes the relationship between urbanization and disease frequency - specifically leprosy and tuberculosis - in four skeletal samples from medieval Denmark using a paleoepidemiological approach. Skeletons from two urban sites (Ole Wormsgade and Ribe Grey Friary) and two rural sites (Øm Kloster and Sejet), all located in the Jutland region of Denmark, were selected for this analysis (n = 204). All skeletons included date to the middle part of the Danish medieval period (AD 1200-1400). Six skeletal leprosy indicators and six skeletal tuberculosis indicators were analyzed, and disease frequencies in the samples were estimated using a probabilistic approach based on lesion sensitivity and specificity. The effect of tuberculosis on survival in urban and rural samples was evaluated using Kaplan-Meier survival analyses. The frequency of leprosy at death varied between four and 19 percent among the four cemeteries with Ole Wormsgade having the highest frequency. The estimated frequency of tuberculosis at death varied between 39 and 69 percent. Here, Sejet cemetery had the highest frequency. There were significant differences in survival for those with and without tuberculosis-related lesions between sites, but there were no significant differences between urban and rural sites. The analyses presented in this paper suggest that disease prevalence in skeletal samples cannot be sufficiently explained by urbanization alone; rather, there are likely other biological and behavioral sources of heterogeneity that are contributing factors to past disease experience.

Ancient DNA study reveals HLA susceptibility locus for leprosy in medieval Europeans.

Leprosy, a chronic infectious disease caused by Mycobacterium leprae (M. leprae), was very common in Europe till the 16th century. Here, we perform an ancient DNA study on medieval skeletons from Denmark that show lesions specific for lepromatous leprosy (LL). First, we test the remains for M. leprae DNA to confirm the infection status of the individuals and to assess the bacterial diversity. We assemble 10 complete M. leprae genomes that all differ from each other. Second, we evaluate whether the human leukocyte antigen allele DRB1*15:01, a strong LL susceptibility factor in modern populations, also predisposed medieval Europeans to the disease. The comparison of genotype data from 69 M. leprae DNA-positive LL cases with those from contemporary and medieval controls reveals a statistically significant association in both instances. In addition, we observe that DRB1*15:01 co-occurs with DQB1*06:02 on a haplotype that is a strong risk factor for inflammatory diseases today.