Plague is a bacterial infection caused by Yersinia pestis, mostly carried by rodents and fleas. Bubonic plague, a form of the plague, is passed to humans by a flea bite from an infected flea. Bubonic plague is characterized by swollen lymph nodes in the armpit or groin. Infection of the bacteria in the lungs can cause pneumonia (pneumonic plague), which causes fever, coughing, and breathing issues. If bubonic plague leads to pneumonic plague, the bacteria may be spread to other people through bodily fluids secreted by coughs of an infected individual. If caught early, bubonic plague can be treated with antibiotics, which clear the body system of the bacteria. However, pneumonic plague is very dangerous and deadly. Between 1-17 cases occur in the United States each year. Between 1000-2000 cases occur worldwide. Therefore it is importantn to seek medical treatment immediately if you believe you are showing symptoms of bubonic or pneumonic plague.