A 4,000-year-old skeleton discovered in India is the oldest
known archaeological evidence of leprosy. The fact that the
skeleton survived suggests the person was an outcast: Hindu
tradition calls for cremation, and only those deemed unfit were
buried. Before this skeleton was found, there was a question
where the disease originated. The latter half of the third
millennium B.C. was a period of social complexity in this
civilization, characterized by urbanization, a system of
writing, standardized weights and measures, monumental
architecture, and trade networks that stretched to Mesopotamia
and beyond. The presence of leprosy in India toward the end of
this period indicates that M. leprae existed in South Asia at
least 4000 years ago, which lends support to the idea that the
disease migrated between Africa and Asia during a period of
urbanization, increasing population density, and regular inter-
continental trade networks.