Outside St. Jørgen: leprosy in the medieval Danish city of Odense

Leprosy was a common and dreaded disease in the Danish Middle Ages (AD 1050-1536). Starting in the second half of the 13th century, leprosaria were established in many Danish towns and cities. In the city of Odense (on the island of Funen, Denmark), the cemetery of the leprosarium was totally excavated, and four nonleprosarium medieval and early modern cemeteries have been partly excavated. This paper explores the frequency of leprosy in the nonleprosarium cemeteries in Odense, and looks for evidence of selective exclusion from the ordinary population. The analyses are based on 733 skeletons from four cemeteries in Odense: the Gray Friars monastery, St. Albani parish church, St. Knuds cathedral, and Black Friars monastery. Seven lesions are scored and, based on known epidemiological properties (i.e., specificity and sensitivity) of these lesions, scores were transformed to statistics characterizing an individual's risk of having suffered from leprosy. This statistical approach remains of primary theoretical value, pending confirmation by independent research groups at other sites. Prevalence of the skeletal manifestation of leprosy at death varied between 0-17% among the different cemeteries in Odense. The highest prevalence was seen in cemeteries with many burials before AD 1400. It is estimated that before AD 1400, between 14-17% of those buried in the nonleprosarium cemeteries suffered from leprosy. In all nonleprosarium cemeteries, there was evidence for selective exclusion of people with facial leprosy lesions. For a short period just up to AD 1300, the cemetery of the Odense leprosarium had, on average, more than 20 yearly burials. The establishment of the leprosarium was followed within a relatively short period by a dramatic decline in the number of sufferers of leprosy in the nonleprosarium cemeteries. The number of yearly burials in the leprosarium cemetery also declined rapidly during the 14th century. The present analyses do not permit conclusions about the reasons for this decline in leprosy prevalence.