Ancient Leprosy Found in the Americas: Study Traces Disease Back Before European Exploration
Ancient presence of leprosy in the Americas revealed through discovery of Mycobacterium lepromatosis, reshaping historical understanding of the disease.
In a groundbreaking development, scientists have identified a species of bacteria that challenges long-held beliefs about the history of leprosy in the Americas. Far from being introduced solely by European explorers and settlers, new research demonstrates that leprosy was present on the continent for centuries prior to their arrival, reshaping our understanding of this ancient and often stigmatized disease.
Historically, experts attributed all cases of leprosy, also known as Hansen's disease, to the bacterium Mycobacterium leprae, and believed its presence in the Americas traced back to European colonization. However, recent findings reveal that a separate bacterium, Mycobacterium lepromatosis, has been infecting humans across North and South America for over a thousand years. This discovery overturns the notion that leprosy was solely imported by outsiders, suggesting instead that it was already endemic among Indigenous peoples.
Dr. Maria Lopopolo, a researcher at the Laboratory of Microbial Paleogenomics at the Institut Pasteur, emphasized the significance of these findings. "This discovery transforms our understanding of the history of leprosy in America. It shows that a form of the disease was already endemic among Indigenous populations well before the Europeans arrived," she explained, underscoring the far-reaching implications of the study.
The multi-institutional research effort began after Mycobacterium lepromatosis was detected in a Mexican patient in 2008 and, intriguingly, in red squirrels in the British Isles years later. Leveraging advanced genetic sequencing techniques, scientists successfully reconstructed the genomes of ancient bacterial samples from Argentina and Canada. The analysis revealed that strains from these distant regions were closely related within the Mycobacterium family, indicating a rapid and widespread dispersal across the continent in pre-Columbian times.
To build their case, researchers collaborated closely with Indigenous communities, international institutions, and archaeologists. Over 800 DNA samples from ancient human remains and recent leprosy cases provided critical evidence. Their results confirmed that Mycobacterium lepromatosis had spread extensively throughout both North and South America well before contact with Europeans, fundamentally altering the narrative surrounding the disease's origins and historical trajectory.
Nicolás Rascovan, lead researcher at the Institut Pasteur, highlighted the broader impact of the study. "We are just beginning to uncover the diversity and global movements of this recently identified pathogen," he said. He added that the findings open up the possibility of unknown animal reservoirs, hinting at further mysteries awaiting discovery about leprosy and its evolution.
Leprosy, according to the Centers for Disease Control and Prevention (CDC), continues to be a serious health concern, affecting nerves, skin, and eyes. It is treatable with antibiotics, but still impacts up to 225 people annually in the United States and approximately 250,000 worldwide. This new research not only provides critical insight into the past but could pave the way for improved diagnosis, treatment, and understanding of infectious diseases in the future.
