How the Black Death Decimated Europe and Asia

By | February 1, 2019

test article image
Devastation of the Black Death. Source: (

From 1346 to 1353, Europe and Asia were plagued with a highly fatal disease which would later come to be known as the Black Death. Though dissenting opinions exist, that disease is believed to have been the bubonic plague, caused by the bacterium Yersinia pestia, which is generally transmitted among rodent populations by fleas. Unlike airborne diseases which thrive in cold weather, the insect-borne plague was more prevalent in warmer seasons and infected high proportions of rural communities rather than the highly populated urban cities.

The most prevailing theory behind the epidemic is that it spread from rats to humans via fleas. The specific culprits indicated are black rats, which commonly live among humans. As the flea-infested rats began to die off, the fleas were forced to find new hosts from which to feed. The nearby humans made easy targets. Once the fleas started biting humans, they became infected and most of them died less than a week after showing symptoms. On average, it took twenty-three days from the time the plague was introduced among the black rats until the first human death. However, more recent studies have suggested it was human fleas, rather than rat fleas, which caused the rapid and wide-spread progression of the epidemic.

test article image
Black rat. Source: (

In any case, by the time of the first death, the disease would already have infected other residents of the community. Because the disease would incubate for three to five days before the host became sick, it was not uncommon for infected humans to attempt to flee their disease-ridden towns, unknowingly bringing the plague with them. Additionally, the infected fleas often came along for the ride. Those fleas would then infect the rats (or humans) of the new community and the whole process would begin anew. Ships were a major contributor to the spread of the plague as they allowed it to travel great distances.