A significant genetic discovery has challenged long-standing beliefs about the history of leprosy in the Americas. A team of researchers successfully reconstructed the ancient genomes of *Mycobacterium lepromatosis*, a rare bacterium responsible for Hansen’s Disease, from human remains that are approximately 4,000 years old in Chile. This finding indicates that this debilitating illness existed in the Americas long before European colonization, suggesting the presence of a unique strain of the disease thousands of years ago. The study involved experts from Germany, Argentina, and Chile, marking the first time that genomes of *M. lepromatosis* have been sequenced.

Unlike its better-known relative, *M. leprae*, which has a documented history in Eurasia, *M. lepromatosis* had remained largely unexplored. Darío Ramirez, a doctoral candidate, noted the initial skepticism surrounding the earlier assumption that leprosy was a colonial-era disease. However, detailed DNA analysis confirmed the ancient pathogen’s identity. Hansen’s Disease has a long history of stigma and fear due to its severe symptoms, including nerve damage and skin lesions.

Historically, scholars believed leprosy arrived in the Americas with European colonizers, as no skeletal remains prior to the contact period showed signs of the disease. The discovery of the pathogen in northern Chilean skeletons has changed that narrative, providing new evidence of the disease’s presence in pre-Columbian times. The implications of this research extend beyond mere historical correction. The findings reveal that both *M. leprae* and *M. lepromatosis* have evolved separately in different regions for thousands of years.

The possibility of *M. lepromatosis* originating in the Americas raises intriguing questions about the disease’s origins, necessitating further genomic studies. The advanced techniques utilized in this research highlight the potential to uncover hidden aspects of disease history in the Americas. The recovery of *M. lepromatosis* genomes sets a precedent for examining other ancient infectious diseases, helping to illuminate the health challenges faced by indigenous populations long before European contact.