The black plague

The black plague was though to be as a result of the bacterium, Yersinia pestis. The disease used rodents and fleas to infect people. The bacteria 

The bacteria spread from person to person through the air (coughs & sneeze), as well as through the bites of infected fleas and rats. These pests where everywhere in medieval Europe! 

It was mainly the fleas & lice on people which caused this bacterium to spread so quickly and widely in the community, 

Yersinia actually caused 3 types of plague in humans. Bubonic, pneumonic, and septicemic. 

Bubonic plague causes fever, fatigue, shivering, vomiting, headaches, giddiness, intolerance to light, pain in the back and limbs, sleeplessness, apathy, and delirium. It also causes buboes: one or more of the lymph nodes become tender and swollen.

Pneumonic plague affects the lungs and causes symptoms similar to those of severe pneumonia: fever, weakness, and shortness of breath. Fluid fills the lungs and can cause death if untreated. 

Septicemic plague is an infection of the blood. Its symptoms include fatigue, fever, and internal bleeding.

The Black Death originated in China in the early to mid-1300s and spread along trade routes westward to the Mediterranean and northern Africa. It reached southern England in 1348 and northern Britain and Scandinavia by 1350.

Back in those times people understanding of bacteria, medicine and hygiene was virtually non-existent. 

Physicians relied on crude methods such as bloodletting, boil-lancing & superstitious practices, like burning aromatic herbs and bathing in rosewater or vinegar. 

A lot of people ended up feeling the cities and avoided going out to places. The only thing which really stoped the spread was social distancing. Eventually sailors where forced to isolate for 2 weeks to 40 days when they docked. 

These days we have antibiotics which work to kill the plague causing bacteria.