For centuries, millions of Europeans suffering from leprosy were shunned by society, made to wear bells that signaled to healthy citizens they were nearby. The infectious illness, also known as Hansen’s Disease, was poorly understood, often believed to be hereditary or a punishment from God. At its height, nearly one in 30 had the disease in some regions; by the 13th century, the number of leper hospitals active in Europe hit its peak at 19,000. Then, in the 16th century, the affliction fell into decline. Soon, it had virtually disappeared from the continent.
The pathogen responsible for leprosy was discovered in 1873 in Norway, squashing previous assumptions about its cause. The earliest written mention of leprosy, one of the oldest-known pathogens to plague humans, appeared in 600 B.C. in China. Historical records show it plagued ancient Greek, Egyptian and Indian civilizations. In 2009, DNA analysis of a first-century man’s remains found in a Jerusalem tomb provided the earliest proven case of leprosy.
Now, DNA sequencing technology has provided clues about the evolution of the bacteria itself. Using well-preserved DNA samples from ancient skeletons, an international team of researchers has sequenced the genome of the pathogen Mycobacterium leprae as it existed in medieval times.
Written By: Marina Korencontinue to source article at blogs.smithsonianmag.com