Leprosy in Medieval Denmark — Osteologicaland epidemiological analyses

摘要

A total of 3033 skeletons from 11 medieval Danish cemeteries and 99 skeletonsfrom the North Scandinavian medieval site of Westerhus were examined for seven lesionsindicative of leprosy. The seven lesions are: rounding to the edge of the nasal aperture, degen-eration of spina nasalis anterior, degeneration of the alveolar process of the pre-maxilla,porosity or perforation of the palatine process of maxilla, sub-periostal exostoses on thefib-ula, general swelling of the shaft of the fibula, and degeneration of the 5th metatarsal bone. The dichotomous scores of these lesions were used to estimate sensitivity and specificityof the lesion scores in relation to leprosy and to estimate sample point prevalence of leprosyat death among adults. In turn the estimates of sensitivity and specificity were used to calcu-late an individual comprehensive statistic, λ, indicating leprosy status. Among adults the λ statistic did not associate with age at death, but this cannot be takenas a sign of lack of selective mortality for leprosy but a combination of the opposing effectsof long waiting time before developing leprosy related lesions and short survival with theselesions. In urban communities sufferers of leprosy were institutionalized when the leprosar-ium was established (in Odense around 1275); in rural communities this did not happen butthe pattern of burial does indicate an internal segregation of sufferers. In the early Middle Ages (AD 1150-1350) the point prevalence at death among adults ofleprosy was higher in rural (25-40 percent) than in urban (10-20 percent) communities, andvillages close to town showed lower frequencies of leprosy than villages situated further awayfrom these centers. Leprosy declined in the late Middle Ages, first in towns and cities, laterin rural communities. In Odense and Malmo it appears that leprosy was effectively elimi-nated by 1350 whereas there were still sufferers of leprosy at Om Kloster around 1550. Lep-rosy appears to have been less common in North Scandinavia than in South Scandinavia, andthere are some indications that leprosy was much more common in the Sarni population thanin the North population of North Scandinavia. It is suggested that the rapid and early decline of leprosy in the towns was caused by thebreaking of chains of infection by institutionalizing the most affected sufferers from leprosy.In rural communities it is suggested that the later decline of leprosy was brought about by anatural vaccination with the active substance in the Calmette vaccine, Mycobacterium bovis.