When a person becomes infected with the bacteria that cause pneumonic plague, the bacteria begin to multiply within the lungs. After one to three days, symptoms of pneumonic plague can begin. The period between becoming infected and the start of pneumonic plague symptoms is called the pneumonic plague incubation period.
With pneumonic plague, the first signs of illness are:
- Shortness of breath
- Chest pain
- Bloody or watery sputum (saliva and discharge from respiratory passages).
The pneumonia progresses for two to four days and may cause respiratory failure and shock. Death from pneumonic plague typically occurs within two to six days after symptoms begin. The mortality rate of pneumonic plague is 75 percent, despite appropriate plague treatment.
Other than the lymphatic system, the lungs are the organ most commonly affected by bubonic plague. Approximately 10 to 20 percent of people with bubonic plague will develop pneumonic plague.
(Click Pneumonic Plague Symptoms for more information.)
In order to make a pneumonic plague diagnosis, the doctor will ask a number of questions and perform a physical exam. During the exam, the doctor will be looking at the skin and listening to the lungs for signs of disease. If the doctor has a high suspicion that a person has pneumonic plague, he or she will recommend certain tests.