Markets and Mycobacteria – A Comprehensive Analysis of the Infuence of Urbanization on Leprosy and Tuberculosis Prevalence in Denmark (AD 1200–1536)

Tuberculosis (TB) and leprosy are two of the consequential maladies of urbanization that can be studied in archaeological samples through systematically examined skeletal indicators and using probabilistic statistical procedures. To test whether TB and leprosy disease prevalence were influenced by growing trends of urbanization in medieval Denmark, skeletons from thirteen cemetery samples (n = 1546) were examined and characterized into varying urban levels based on historic and archaeological sources. Prevalence was estimated using a probabilistic approach based on sensitivity and specificity measures of lesions associated with TB and leprosy. The estimated TB prevalence was significantly higher than that of leprosy across all sites and urban levels, although for both TB and leprosy, rural and transitional sites (urban 1) had significantly higher disease prevalence. Among individual sites, leprosy was most common in rural Sct. Alberts (28%), Sejet (18%), and transitional urban Ole Wormsgade (22%) with other sites ranging from 0% to 6%. For TB, sites with the highest prevalence were found in rural Sct. Alberts (100%) and urban Sct. Drotten (73%) with the remaining sites ranging from 7% to 59%. The findings support the hypothesis that individuals with visible facial lesions were routinely isolated and buried in urban leprosaria, thus contributing to the lower prevalence of the disease in parish cemeteries in towns. Comparatively higher TB prevalence may reflect increased contact through widening economic networks between urban and rural communities.