New Research Challenges Historical Narrative on Leprosy in the Americas
For years, historians believed that leprosy was brought to the Americas by European settlers. However, groundbreaking research is now challenging this long-held belief, suggesting that Indigenous Americans were already suffering from the disease centuries before the arrival of Europeans.
The primary cause of leprosy, a bacterium known as Mycobacterium leprae, is still believed to have been introduced to America by Europeans. However, a lesser-known culprit, Mycobacterium lepromatosis, was already present among Indigenous populations long before European contact.
A recent study conducted by an international team of researchers analyzed ancient human remains from Canada and Argentina, dating back over a thousand years, and found evidence of Mycobacterium lepromatosis in their DNA.
“This discovery reshapes our understanding of leprosy history in America,” stated genomicist Maria Lopopolo from the Institut Pasteur in France. “It indicates that a form of the disease was endemic among Indigenous populations prior to European colonization.”
Mycobacterium lepromatosis was first identified in a patient in the US in 2008 and has since been discovered in red squirrels in the UK. Researchers suggest that the bacterium may have spread from the US to the UK in the 19th century.
The researchers collaborated with local Indigenous communities to analyze DNA samples from ancient and modern human remains. By constructing a genetic family tree of leprosy bacteria, they uncovered a rapid spread of Mycobacterium lepromatosis across the Americas.
Despite the geographical distance, the ancient Canadian and Argentinian samples showed remarkable genetic similarities, indicating a swift spread of Mycobacterium lepromatosis throughout the continent.
According to the DNA timeline, different strains of Mycobacterium lepromatosis diverged from a common ancestor over 9,000 years ago. The researchers believe that there are likely more diverse forms of the bacterium yet to be discovered in the Americas.
“We are only scratching the surface of the diversity and global movement of this newly identified pathogen,” said biologist Nicolás Rascovan from the Institut Pasteur. “This study suggests the existence of unknown animal reservoirs.”
This research provides valuable insights into the history of the Americas and leprosy, offering crucial data points on the disease’s evolution and diversification.
Infectious diseases have played a significant role in the Americas’ history, with European contact introducing new pathogens to Indigenous communities. The complexity of the leprosy narrative in the Americas is now coming to light.
Approximately 200,000 new cases of leprosy are reported globally each year, but modern drugs can effectively treat and cure the disease.
“This study demonstrates how ancient and modern DNA can reshape the history of a human pathogen and enhance our understanding of infectious disease epidemiology,” added Rascovan.
The findings of this study have been published in Science and offer a fresh perspective on the complex history of leprosy in the Americas.
