Black death:

Black Death, pandemic that ravaged Europe between 1347 and 1351 , taking a proportionately greater toll of life than any other known epidemic or war up to that time. The Black Death is widely thought to have been the result of plague, caused by infection with the bacterium Yersinia pestis. Key points In 1348 - 49, the Black Death swept across Europe, killing up to half of the population. There were two main types of plague: bubonic and pneumonic. Bubonic plague , a potentially fatal infection spread mainly by fleas, still exists. Antibiotics can treat this form of the plague . The Black Death was the second pandemic of bubonic plague and the most devastating pandemic in world history. It was a descendant of the ancient plague that had afflicted Rome, from 541 to 549 CE, during the time of emperor Justinian.