New research indicates that leprosy was present in the Americas long before European explorers arrived, challenging previous historical assumptions about the disease’s origins.
Recent findings from a team of scientists at the Institut Pasteur in Paris, in collaboration with a U.S. university, suggest that the bacterium responsible for leprosy, or Hansen’s disease, was present in the Americas long before the arrival of European explorers. This revelation stems from the discovery of a second species of bacteria, Mycobacterium lepromatosis, which alters the historical narrative surrounding the disease.
Historically, it was believed that leprosy was caused solely by the bacterium Mycobacterium leprae and that it was introduced to the Americas by early European explorers and settlers. However, the identification of Mycobacterium lepromatosis indicates that a strain of leprosy was already endemic among Indigenous populations in the New World, predating European contact by approximately 1,000 years.
Dr. Maria Lopopolo, the first author of the study and a researcher at the Laboratory of Microbial Paleogenomics at the Institut Pasteur, emphasized the significance of this discovery. “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 stated in a recent news release.
The study, which involved advanced genetic techniques, began after Mycobacterium lepromatosis was identified in a Mexican patient in 2008 and subsequently in red squirrels in the British Isles in 2016. Researchers reconstructed the genomes of Mycobacterium lepromatosis from ancient individuals in Argentina and Canada, revealing that the two strains from these regions were genetically similar. This suggests that the bacteria spread rapidly across the continent.
The results confirmed that Mycobacterium lepromatosis had already established itself throughout North and South America prior to European exploration. The research team collaborated with Indigenous communities, various international institutions, and archaeologists, studying over 800 DNA samples from ancient human remains and recent medical cases showing signs of leprosy.
Nicolás Rascovan, the lead author of the study at the Institut Pasteur, remarked on the broader implications of their findings. “We are just beginning to uncover the diversity and global movements of this recently identified pathogen,” he said. “This study allows us to hypothesize that there might be unknown animal reservoirs.”
Leprosy, as noted by the Centers for Disease Control and Prevention (CDC), can affect the nerves, skin, and eyes of patients and is treatable with antibiotics. In the United States, approximately 225 individuals are diagnosed with Hansen’s disease each year, while around 250,000 cases are reported globally, according to the CDC.
This groundbreaking research not only reshapes the historical understanding of leprosy in the Americas but also highlights the need for further exploration into the disease’s origins and its impact on Indigenous populations. The study underscores the importance of interdisciplinary collaboration in advancing our understanding of infectious diseases and their histories.
As scientists continue to investigate the complexities of Mycobacterium lepromatosis, the findings may lead to new insights into the disease’s transmission and its long-standing presence in the Americas, ultimately contributing to a more nuanced understanding of human health and history.
For more information, refer to the original study and news release from the Institut Pasteur.