Leprosy in Bronze Age Thailand

Kate Domett1*, Rossella Paba1, Melandri Vlok2, Nancy Tayles3, Naruphol Wangthongchaicharoen4, and Nicola Czaplinski5

Osteological evidence for leprosy in prehistoric Thailand remains sparse and largely confined to the Iron Age; this study presents a new case from Ban Non Wat that establishes the presence of leprosy in the early Bronze Age (ca. 1000–900 BC). Lesions were assessed for morphology, distribution and bilateral patterning, and evaluated within a biologically informed differential‑diagnostic framework that emphasises rhinomaxillary changes and peripheral neuropathic skeletal alterations as key criteria for leprosy. A young adult/late adolescent individual (Burial 443) exhibited rhinomaxillary syndrome alongside post‑cranial changes in both upper and lower limbs. Bronze Age 2 at Ban Non Wat was a period of social transformation marked by increased mortuary wealth; Burial 443 contained a long grave with 25 pottery vessels and numerous personal ornaments, and there was no osteological or contextual evidence of marginalisation in death. The new case suggests that Mycobacterium leprae may have a deeper history in mainland Southeast Asia than previously recognised. These findings, together with comparative and biomolecular approaches, will inform larger evolutionary and palaeopathological studies aimed at reconstructing the antiquity, transmission pathways and sociocultural implications of leprosy in the region.