For centuries the origin was unclear until modern times. Back then, they blamed the plague mostly on their superstitious beliefs. They first blamed it on the Jews because they thought that God was punishing them for not being Christian. The Paris doctors blamed it on the sun and stars but without any scientific reason. Because of that theory, patients were advised not to sleep during the day. But after centuries we found the root cause. The Bubonic Plague was in fact transmitted through fleas that fed on the rats that had the Bubonic Plague. Then the now infected fleas, gave it to the Europeans one at a time. They say that the rats originated from The Gobi Desert in Asia.
The symptoms were unbearable. It first started with a severe headache and redness in the eyes. Shortly after inflammations, a hacking cough, hoarseness, and an itchy tongue. Then, these symptoms were followed by severe intestinal upsets which included vomiting and acute diarrhea. Their temperatures were high and they would break out in reddish spots too. There would be apple sized open sores called Buboes all over their body. The later stages of the Black Death included developing delirium. Even though The Black Plague was deadly, there were a few survivors. Those who survived had terrible scars. Some lost their eyesight or their memory. But it seemed that doctors just made the disease worse in some ways.
The doctors in the Middle Ages were known as Butchers.