The document discusses the bubonic plague, also known as the Black Death, which caused an estimated 50 million deaths in the 14th century. It is caused by the Yersinia pestis bacteria, usually found in small animals and their fleas. People infected with plague develop flu-like symptoms within 3-7 days. The most common form during the Black Death was bubonic plague, which was spread by fleas living on black rats that would then bite humans. Symptoms of bubonic plague include swollen and painful lymph nodes, called buboes, as well as fever, chills and muscle cramps. Antibiotics like streptomycin, doxycycline and ciprofloxacin can effectively