causitive agent: bacterium Yersinia pestis

What is the Plague?

Plague is a deadly infectious disease that is caused by the enterobacteria, Yersinia pestis, named after the French-Swiss bacteriologist Alexandre Yersin. Plague can be spread in the air, by direct contact, or by contaminated undercooked food or materials. There are different types of plague that effect different areas. These are the bubonic plauge in lymph nodes, septicemic plague in blood vessels, pneumonic plague in lungs, etc.

What are the possible complications of the Plague?

Course of disease

Bubonic plague infects your lymphatic system (immune system), causing inflammation. Untreated, it can move into the blood and cause septicemic plague, or to the lungs, causing pneumonic plague. When the bacteria multiply in the lungs, you have pneumonic plague—the most serious form of the disease. When a person with pneumonic plague coughs, the bacteria from their lungs are expelled into the air. Other people who breathe that air can also develop this highly contagious form of plague, which can lead to an epidemic. When the bacteria multiply in the bloodstream, it is called septicemic plague. When untreated, both bubonic and pneumonic plague can lead to septicemic plague.

Relative Frequency of disease