Plague was used as a bacteriological weapon by the Imperial Japanese Army. These weapons were provided by Shirō Ishii’s units and used in experiments on humans before being used on the field. In 1940, the Imperial Japanese Army Air Service bombed Ningbo with plague-carrying fleas. During the Khabarovsk War Crime Trials, the accused Major General Kawashima testified that, in 1941, 40+ members of Unit 731 air-dropped plague-carrying fleas on Changde, causing epidemic plague outbreaks.
Bubonic plague infection causes tiny blood vessels in the hands and fingers to clog up and cut off circulation. Without blood, the flesh dies and turns black (called "gangrene"). This is why in the Middle Ages bubonic plague was called "the Black Death." In the 14th century it killed an estimated 25 million people, or 30–60% of the European population.
10 things you (probably) didn’t know about the Black Death - It is one of the worst catastrophes in recorded history – a deadly plague that ravaged communities across Europe, changing forever their social and economic fabric. But how much do you know about the Black Death? | History Extra
Ring Around The Rosie. This rhyme dates back to the Great Plague of London in 1665. The symptoms of bubonic plague included a rosy red ring-shaped rash, which inspired the first line. It was believed that the disease was carried by bad smells, so people frequently carried pockets full of fresh herbs, or "posies." The "ashes, ashes" line is believed to refer to the cremation of the bodies of those who died from the plague.