Leprosy in Americas predated arrival of Europeans

[guy]

For a long time, it was thought that leprosy, primarily caused by Mycobacterium leprae, was introduced to the Americas during European colonization. However, discovering a second pathogen, M. lepromatosis, mainly affecting people in the Americas, challenges this idea. Research shows that M. lepromatosis infected humans in the Americas before Europeans arrived. By analyzing 389 ancient and 408 modern samples, we've expanded the genetic data available for this species. The phylogenetic analyses revealed distinct clades of M. lepromatosis that infect humans, with one dominant strain in North America since colonial times. The presence of thousands of years-old strains in North and South America suggests that M. lepromatosis was widespread during the Late Holocene. M. lepromatosis leprosy has a long history in the Americas, predating European arrival.

 

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Led by scientists from the Laboratory of Microbial Paleogenomics at the Institute Pasteur, also associated with the CNRS, and the University of Colorado, in collaboration with Indigenous communities and over 40 scientists from international institutions including archaeologists, this study analyzed DNA from nearly 800 samples, including ancient human remains (from archaeological excavations) and recent clinical cases presenting symptoms of leprosy.

 

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The results confirm that M. lepromatosis was already widespread in North and South America long before European colonization and provide insights into the current genetic diversity of pathogenic Mycobacteria.

"This discovery transforms our understanding of the history of leprosy in America," said Dr. Maria Lopopolo, the first author of the study and researcher at the Laboratory of Microbial Paleogenomics at the Institute Pasteur. "It shows that a form of the disease was already endemic among Indigenous populations well before the Europeans arrived."

 

 

Leprosy existed in the Americas long before the arrival of Europeans, study reveals

[guidoLaMoto]

Interesting.

There is evidence (bone lesions) that TB (Mycobacterium tuberculosis) existed as far back as the Neandertals, so it's reasonable to assume that other species of Mycobacterium are that old too....

Speciation doesn't occur because one indvidual developed a novel genome and then passed it along to a subsequent population, but rather, because the same novel genome developed  spontaneously and contemporaneously in a significant portion of individuals in a population, and then selection &/or random drift increases that gene frequency in the population. ...

M. lepromatosis may have evolved in multiple locations simultaneously (on a time scale of centuries or even millennia) rather than sequential "spreading" of the bug over geography. ...Compare it to the invention of, say, the bow & arrow at multiple locations around the world at roughly the same time in human history.