Medieval Mondays: Why Did Leprosy Disappear from Europe?

They are one of the enduring images of the Middle Ages. With their horrible open wounds and missing fingers, lepers caused fear and revulsion wherever they went. In some places, they still do. While leprosy is hard to catch, the simple medicine of the time didn't know this and had no cure. A disease so horrible, people thought, must be contagious.

It was also considered a judgement from God. In some areas, lepers were forced to stand in an open grave as a priest declared them dead. They were forbidden from living in towns or cities and had to wear bells in order to warn people of their presence.

Leprosy was widespread, with up to one in 30 people affected in some areas. But by the 16th century it was disappearing. Why?

A recent archaeological research project set out to answer this question. A team of archaeologists and biologists exhumed the bones of medieval lepers and sequenced the DNA of five strains of the leprosy bacteria. They found no significant difference between medieval leprosy and the strains still found today in Asia. The disease hadn't become any less virulent, so why did it die out?

It appears it was the victim of its own success. People have a genetic level of resistance to particular diseases. Those who were most susceptible died from it and didn't pass on their genes. Leprosy was one of the few grounds for divorce in medieval Europe. Only those individuals who had stronger resistance to leprosy remained, and thus the disease all but died out in Europe.