The Black Death was caused by ships carrying rats in Central Asia which had fleas that were carrying the Black Death. So when they arrived in Italy in the mid 1300's they devastated all of Europe killing 33% of their population. This lead to a serious labor shortage all over Europe which lead to workers demanding higher wages. The landlords refused to pay them. The Black Death also hurt the church. The people prayed and gave money to the church to save their family and they still died and the people blamed the church.
If you get the Bubonic Plague or the Black Death the symptoms include fever, chills, vomiting, diarrhea, aches and pains, and probably even death.