Black death(plague)
black death was a pandemic that destroyed Europe between 1347 and 1351 take many lives then any other known pandemic or war up to that time.
The black death was believed to be plague caused by infection with the bacterium Yersinia pestis. While no one knew what caused it,it was unstoppable.People who were infected by the unknown Black death would begin to swell and develop growths, the growths would then become huge blackish blue apple sized pumps.These would then ooze into various kinds of body fluids.With these kinds of unknown pumps people would then start to show symptoms like pain,chills,sweating,upset stomach and diarrhea. After that it would soon be followed by death.
According to the people who noticed the first hand affects,it only took physical contact with people who were sick to pass on the disease to others.Many people who appeared perfectly fine few days would be pronounced dead a few days later.It was possible for someone to survive few weeks before they died.Those ones with the disease would be perfectly normal few days before so no one would know they were infected.The plague killed countless animals such as chickens,pigs,cows,goats and sheep.
https://www.britannica.com/event/Black-Death