Leprosy, a neglected disease affecting thousands worldwide, has been misunderstood as being introduced to the Americas by European colonizers. However, recent research reveals that leprosy existed in the region for at least 1,000 years before the arrival of Europeans.
A team of scientists from the Institut Pasteur and various institutions in America and Europe found evidence of a second species of bacteria responsible for leprosy, Mycobacterium lepromatosis, infecting humans in the Americas. This discovery was published in the journal Science.
The researchers analyzed DNA from nearly 800 samples, including ancient human remains and recent clinical cases presenting symptoms of leprosy. They found that M. lepromatosis was already widespread in North and South America before European colonization.
Genetic analysis revealed that ancient strains of M. lepromatosis from Canada and Argentina were surprisingly genetically close, despite being separated by thousands of kilometers. This suggests a rapid spread of the pathogen across the continent within just a few centuries.
The study also identified new lineages, including an ancestral branch that continues to infect humans in North America today. The findings highlight the recent ability of the pathogen to cross continents and introduce new strains to previously unaffected areas.
This research marks a significant shift in our understanding of leprosy’s history in America and provides insights into the current genetic diversity of pathogenic Mycobacteria. The project was conducted in collaboration with Indigenous communities, who were involved in decision-making regarding the use of ancestral remains and interpretation of results.
Source: https://phys.org/news/2025-05-leprosy-americas-europeans-reveals.html