Leprosy, Armadillos and the Long Memory of Disease

Diseases we thought were brought from Europe circulated in the Americas before Columbus...

On my way back from Tajikistan, I had a chance to catch up on some reading and on some of the latest research in fields I am interested in.

One of the great misconceptions of history is that the past is dead. Yet the past persists - sometimes in our politics, sometimes in our landscapes, and sometimes, quite literally, in our bodies. A fascinating new study reveals that one of humanity’s oldest and most misunderstood diseases - leprosy - has a much longer and more complex history in the Americas than we thought. And, crucially, it never went away.

Leprosy (or Hansen’s disease) has long been associated with biblical antiquity, medieval European asylums, and colonial encounters. Its very name conjures images of isolation, stigma, and mystery.

But the assumption for decades has been that Mycobacterium leprae, the bacterium that causes leprosy, arrived in the Americas with Europeans: with sailors, conquistadors, and enslaved populations bringing with them pathogens alien to the so-called New World. This is usually a key element of the ‘Columbian Exchange’ model that I explored in The Earth Transformed - a world remade by transoceanic flows of goods, ideas, animals and diseases.

The truth, as this new research demonstrates, is both more complicated and remarkable.

Drawing on ancient DNA recovered from human remains in the Caribbean and Brazil, and from wild armadillos and primates in modern South America (!), the team behind this study shows that leprosy was already circulating in the Americas before European contact.