Jerusalem -- What caused leprosy -- a widely dreaded disease inmedieval Europe -- to fade from the scene? By the 16th century, thescourge had practically disappeared there.
The reason seems to be, say researchers at the Hebrew University ofJerusalem and in London, that tuberculosis, a far more deadly disease,overtook leprosy, killing millions throughout Europe.
Their conclusion is based upon the examination of DNA fromhuman remains from the ancient and medieval periods in Israel andEurope. In these examinations, the scientists found traces of bothleprosy and tuberculosis bacteria in 42 percent of the cases.
The findings on the relationship between leprosy andtuberculosis were reported in a recent edition of the British RoyalSociety Proceedings B by Dr. Mark Spigelman, a visiting professor atthe Hebrew University Faculty of Medicine and of the University CollegeLondon; Prof. Charles Greenblatt of the Sanford F. Kuvin Center for theStudy of Infectious and Tropical Diseases at the Hebrew University'sFaculty of Medicine; and Dr. Helen Donoghue of University CollegeLondon.
The earliest case of co-infection of both leprosy andtuberculosis was found by the researchers in the DNA from a bodydiscovered in a 1st century CE burial cave in Jerusalem. This promptedthe investigators to re-examine DNA samples from other ancient sitesthat they and their colleagues had worked on previously. In doing so,they found leprosy and tuberculosis bacteria in remains from a 4thcentury CE Egyptian shrine that was known to have been visited bylepers, from a 10th century burial ground in Hungary, and from aViking-age cemetery in northern Sweden.
The conclusion drawn by the researchers from these multiplesigns of co-infection of leprosy and TB bacteria is that those withleprosy, which was seldom fatal, were weakened to the extent that theybecame highly vulnerable to the "big killer," tuberculosis. This wasexacerbated by the lives of deprivation that the lepers were forced tolive as social outcasts.
Ultimately, the scientists theorize, so many of the lepersdied of tuberculosis until there were too few of them to further spreadleprosy. TB, meanwhile, was increasingly on the rise as people in theMiddle Ages migrated to urban centers, where crowding and poor sanitaryconditions provided a fertile breeding ground for the spread of thekiller disease.
Today, tuberculosis, though curable, is still a major,long-term, epidemic disease, with millions of new cases reported aroundthe world each year.
Materials provided by The Hebrew University of Jerusalem. Note: Content may be edited for style and length.
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