Bubonic plague is a severe bacterial infection caused by gram-negative bacillus Yersinia pestis
, which can cause three distinct forms of illness: bubonic, septicemic, and pneumonic plague. Bubonic plague manifests in the form of swollen lymph nodes, known as buboes historically. Bubonic plague may progress to both the septicemic and pneumonic forms if left untreated.
Bubonic Plague was first recorded in the 1st century and since then it has been estimated to have claimed over 200 million lives. The disease was not recognized as a true pandemic until 1328 when many people worldwide succumbed to it. Changes in lifestyle during the middle ages have been blamed for the virus reaching pandemic levels. Trade routes allowed easy access for the disease carrying rats and highly populated areas with poor sanitary conditions provided an ideal breeding ground for plague to reach full ferocity. Never before did any illness provoke so much fear and terror, destroy economies and create social upheaval as Bubonic Plague.
Although the plague is considered a disease of the Middle Ages outbreaks are still reported worldwide, the most recent to my knowledge in 2006 in the Democratic Republic of the Congo. The disease can now be treated with antibiotics although the most virulent form Pneumonic plague will still kill if not treated within 24 hours.
The fleas bite and suck the infected blood from the rat then bite and regurgitate the blood into human body thus infecting humans who could then spread it rapidly to each other. Symptoms include fever and painful swellings of the lymph glands. It also causes red spots on the skin which would later turn black.