Reconstructing the Epidemiology of Medieval Leprosy: Preliminary Efforts with Regard to Scandinavia

RECONSTRUCTING THE EPIDEMIOLOGY OF MEDIEVAL LEPROSY: PRELIMINARY EFFORTS WITH REGARD TO SCANDINAVIA STEPHEN R. ELL* Introduction Since the diagnosis of leprosy in the period between 1250 and 1550 in Denmark has been shown to have been accurate [1-6], wè can at least speak confidently of leprosy as we know it in regard to that region and time. While there are excellent reconstructions of the daily life ofleprosy patients and provocative efforts at summarizing the literary imagery surrounding the disease, as well as many works on the medical writing of the period, notable among recent works being those of Demaitre and Dois [6-9], we know nothing of the epidemiology of the disease beyond estimates of the number of institutionalized patients, mainly in Spain and England around 1300 [6, 10]. This is not a criticism, because no records are known to exist from which such information might be gleaned. The same skeletal remains initially employed by M0ller-Christensen to demonstrate that the persons buried in the cemetery of the leprosarium of St. Jorgens Hospital in Naestved, Denmark, actually suffered from leprosy can, however, with the aid of another generation of medical knowledge be used to reconstruct an overall epidemiology for the region . Specifically, the analysis of certain bone changes, in conjunction with the sex distribution of cases, make possible such an epidemiologic assessment. In arriving at this end, it is necessary to review the skeletal remains themselves. Then we must consider the social, religious, and legal situaThe author expresses his gratitude to Director H. Koch of the Medinsk-Historiske Museet in Copenhagen for his gracious assistance in reviewing the Naestved materials. ?Department of Radiology, Box 429, University of Chicago Medical Center, 5841 South Maryland Avenue, Chicago, Illinois 60637.© 1988 by The University of Chicago. AU rights reserved. 0031-5982/88/3104-0589$01.00 496 I Stephen R. Ell ¦ MedievalLeprosy TABLE 1 Summary of Statistics Based on Data from Malaysia Statistics Sample size ............................................................ 25 Descriptive statistics: Average number of years of untreated LL ............................. 9.1 Average percent of alveolar bone loss .................................. 32.0 Raw rate percent loss/year ............................................ 3.6 Test of randomness (Student t and ?2, P) ................................ -001 Regression analysis: Slope ................................................................ 2.4 Correlation coefficient ................................................ .62 Regression analysis, employing interactive outlier rejection: Sample size .......................................................... 21 Slope of regression line ............................................... 1.7 Correlation coefficient ................................................ .83 P ....................................................................01 Note.—Cases employed initially were those wherein the history led to a reliable estimate of the duration ofuntreated lepromatous leprosy (LL). Cases with unclear histories or interrupted treatment were excluded. The effect of intermittent treatment was unclear but could not apply to the Middle Ages. Rejected as outliers were three endentulous cases— all patients in their late seventies at the time of the study, an age not achieved by any of the medieval subjects. Another case with 15 percent bone loss and only one year ofdisease alleged was rejected as totally inconsistent with all other data. Source.—See Ell [5]. tion of leprosy patients, in order to correct for any biases that might vitiate purely statistical data. Finally, having elaborated an overview of the epidemiology of leprosy in Scandinavia in the thirteenth through sixteenth centuries, we will consider how that epidemiology may be extrapolated to other parts of medieval Europe. The Skeletal Remains and Their Significance In 1953, Vilhelm M0ller-Christensen began to publish the results of a series of excavations associated with the St. Jorgen's leprosarium at Naestved. As the work progressed, M0ller-Christensen established as pathognomonic of leprosy certain facial bone changes, the so-called facies leprosa, which became an accepted feature ofleprosy when demonstrated among living African patients [1, 1 1]. These facial bone changes are complex, involving destruction of the nasal bone, resorption of the anterior alveolar process of the maxilla, coarsening of thé sinuses, and thickening and squaring of the orbits. Most important for our purposes is the fact that recent work has shown that, in general, the amount ofloss ofalveolar maxillary bone—a midline phenomenon, which results in the loss of the central incisors and canine teeth ultimately—correlates with the duration ofuntreated lepromatous leprosy [12; data from this article form the basis of table 1 and figs. 1 and 2]. Hoo Nah, Marks, and Perspectives...