Overview

• The study published in Science recovered Mycobacterium lepromatosis DNA from ancient remains in Canada and Argentina dating back more than 1,000 years.
• Genetic analysis indicates the bacterium diversified in the Americas for over 9,000 years and spread rapidly across North and South America prior to European contact.
• Researchers trace a 19th-century introduction of this strain to the British Isles, where it persists in red squirrel populations today.
• The project was carried out in collaboration with Indigenous communities who guided the ethical handling of ancestral remains and data interpretation.
• Given its deep history and genetic diversity, M. lepromatosis is identified as a potential emerging pathogen distinct from the more common M. leprae.