Ancient News: The Spread of Leprosy in the Bronze Age

By Owain Williams

In the Bronze Age, trade routes connecting South Asia and Arabia carried more than just metal, pottery, and other goods. Pathological analysis of the remains of several people from the site of Dahwa, Oman, dated to ca. 2500–2000 BC, has revealed the earliest known appearance of leprosy outside of South Asia.

Pottery finds, as well as the appearance of copper-alloy cymbals with morphological links to the Indus Valley demonstrates how Dahwa, located near the coast of Oman, had close trading ties with South Asia. The inhabitants of Dahwa, known as the Umm an-Nar people, likely exported copper. It has previously been assumed that pathogens travelled along these trade routes, but the study remains from the site provides strong direct evidence for such transmission. In the Bronze Age, Oman – then known as Magan – also had trade connections with Mesopotamia, with Sargon of Akkad claiming that his port hosted traders from there. These connections likely facilitated the further spread of leprosy.

According to the study, leprosy “is caused by infection with ... an intracellular parasite that affects the skin, peripheral nerves, bones, endothelial cells, mucous membranes, and eyes”. If left untreated, leprosy leads to the disfigurement of the infected, which means the remains of those infected with leprosy throughout history are easily identifiable. However, due to the preservation of the remains from Dahwa, three of the most complete jaw bones were scanned using micro-computerized tomography. According to the study, this was “the first published micro-CT characterization of lesions associated with lepromatous leprosy in isolated archaeological maxilla fragments”.

Trade routes have contributed to the spread of disease throughout history. The most famous instance is the Black Death that ravaged Europe in the fourteenth century. In Late Antiquity, the Plague of Justinian also appears to have been carried by traders, with Procopius noting that it was first reported in the port city of Pelusium in Egypt. 

You can read the full study here.