Detection of leprosy in ancient human skeletal remains by molecular identification of Mycobacterium leprae.

We isolated ancient DNA from skeletal remains obtained from a South German ossuary (approximately 1400-1800 AD) and from a 10th century Hungarian cemetery partially indicating macromorphologic evidence of leprosy. In samples taken of 2 skulls from Germany and of 1 hard palate from Hungary, Mycobacterium leprae-specific fragments of RLEP1 and RLEP3 were amplified using polymerase chain reaction (PCR), thereby confirming their specificity by sequencing. In another case, PCR with primers targeting IS6110 of Mycobacterium tuberculosis gave positive results only for a mandibular specimen. No signal for any mycobacterial DNA was observed in samples from 2 Hungarian foot bones. In ancient material, osseous involvement of M leprae may be detected and distinguished from other mycobacterial infections by specific PCR. In the small bones of leprous hands and feet, not enough M leprae DNA seems to be present for detection. This supports the view that rhinomaxillary leprous alterations result from direct bacterial involvement, while osseous mutilations of hands and feet result from a nervous involvement and/or secondary infections due to small lacerations of the overlying soft tissues.