The Black Death that ran through China and across Europe in the 14th century is considered the worst plague in recorded history.
Depending on the way the virus was contracted, 70 to 90 percent of those exposed to the plague died from it. During a five-year period, from 1347 to 1352, over 25 million people in Europe alone were wiped out.
That was the worst plague; however, it wasn’t the worst epidemic. What’s the difference? The plague is a specific bacterial infection, but many of the worst epidemics have been caused by viruses.
The worst epidemic was not a plague but a flu that swept the world from 1918 to 1919. The first reported case was in Kansas in 1918, and from there it spread like wildfire.
Eighteen months later, the virus vanished as mysteriously as it had appeared, after between 25 and 37 million people had died from the disease.
At no other time in recorded history have so many people died from one affliction in so little time.