In the 1340s, an outbreak of bubonic plague swept through Europe. The most common form of plague, the bubonic plague is a bacterial infection found mainly in rodents. It creates skin sores which become black, hence the name ‘Black Death’.
An epidemic in the 14th century, known as the Black Death, reduced Europe’s population by around 50 per cent.
While statistics vary, the 14th-century plague was deadly, killing an estimated 25 million people, almost a third of the continent’s population. It paved the way for numerous public health initiatives, such as the use of quarantine and the establishment of hospitals.
The event has been credited with disrupting Europe’s feudal system, setting the scene for the cultural revolutions of the Renaissance.
How did the Black Death spread?
The habitat of choice for the bacterium Yersinia pestis is the body of a rodent. But every once in a while, it leaves its comfort zone and starts killing people.
Few diseases have been as influential on the course of human history as the plague. which is transmitted by the bites of fleas - which are themselves spread by rats – and passed between people via body fluids.
Bubonic plague causes grotesque pustulous swellings in the groin, neck and armpits and, if untreated, kills around 50 per cent of victims. Pneumonic plague infects the lungs, and is 100 per cent fatal. If it gets into the blood, it kills blocks of tissue and turns them black. Happily, all three types of infection respond to modern antibiotics.
Outbreaks still occur in Madagascar, Democratic Republic of the Congo, and Peru, and a fatal case of pneumonic plague, contracted from an infected animal carcass, was reported in Arizona in July 2025
