The
Nabe-kaburi is a unique burial method, the purpose of which is shrouded in mystery. The burials were performed during the 15(th) to 18(th) centuries in eastern Japan, and involved covering the heads of the deceased with
iron pots or mortars. The identification of
leprosy-specific osteological lesions among some of the excavated remains has led to the suggestion that
Nabe-kaburi burials were a reflection of the social stigma against certain
infectious diseases, such as
leprosy,
tuberculosis or
syphilis. However, molecular evidence for the presence of disease has been lacking. The goal of this study was to detect Mycobacterium leprae (M. leprae)
DNA in archaeological human
skeletal remains from
Nabe-kaburi burials. The paleopathological data from three
Nabe-kaburi burials were re-evaluated before small samples were taken from affected and control areas.
DNA was extracted and used as a template to target the M. leprae-specific
DNA using a combination of whole genome amplification, PCR analysis and
DNA sequencing. M. leprae
DNA fragments were detected in the two sets of
skeletal remains that had also shown paleopathological evidence of
leprosy. These findings provide definitive evidence that some of the
Nabe-kaburi burials were performed for people affected by
leprosy. Demonstration of the presence of M. leprae
DNA, combined with archeological and anthropological examinations, will aid in solving the mystery of why
Nabe-kaburi burials were performed in medieval Japan.