Pre-European contact leprosy in the Americas and its current persistence

Area of Science:

• Microbiology
• Paleopathology
• Genetics

Background:

• Leprosy in the Americas was historically attributed to European introduction.
• The discovery of Mycobacterium lepromatosis, primarily in the Americas, challenged this understanding.

Purpose of the Study:

• To investigate the historical presence and diversity of Mycobacterium lepromatosis in the Americas.
• To determine if M. lepromatosis infections existed in the Americas before European colonization.

Main Methods:

• Screening of 389 ancient and 408 contemporary human samples.
• Phylogenetic analysis of Mycobacterium lepromatosis genetic data.

Main Results:

• Evidence confirms M. lepromatosis infected humans in the Americas prior to European contact.
• Phylogenetic analyses identified distinct human-infecting clades of M. lepromatosis.
• Ancient strains of M. lepromatosis were detected in both North and South America.

Conclusions:

• Mycobacterium lepromatosis has a long-standing history in the Americas, predating European arrival.
• The pathogen may have been widespread in the Americas during the Late Holocene.
• This finding necessitates a re-evaluation of leprosy's introduction and history in the Americas.