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What does genetic evidence suggest about the ancient origins of Mycobacterium leprae?

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Sign reading Gandhiji Prem Nivas Leprosy Centre Titagarh conducted by Missionaries of Charity, with a crucifix above the sign on a decorated building facade. — leprosy The Gandhiji Prem Nivas is a center for people with leprosy that was established by Mother Teresa in 1958 and is run by the Missionaries of Charity in Titagarh, India.

Genetic evidence suggests that Mycobacterium leprae, the bacterium responsible for leprosy, likely evolved approximately 100,000 years ago in either eastern Africa or southwestern Asia.1

Following its emergence, the bacillus appears to have migrated both eastward and westward. This dispersal led to the development of distinct genetic subtypes: one in Asia and another in Europe and North Africa. Later, as the disease was introduced into western Africa by Europeans or North Africans, the bacillus evolved into yet another unique subtype. This genetic analysis provides a broader evolutionary perspective on the disease's origins, which differs from traditional historical theories that focused on its spread through specific military campaigns or trade routes.1