Pneumonic plague is a severe lung infection caused by the bacterium Yersinia pestis. Symptoms include fever, headache, shortness of breath, chest pain, and cough. They typically start about three to seven days after exposure. It is one of three forms of plague, the other two being septicemic plague and bubonic plague. Pneumonic plague is a severe lung infection caused by the bacterium Yersinia pestis. Symptoms include fever, headache, shortness of breath, chest pain, and cough. They typically start about three to seven days after exposure. It is one of three forms of plague, the other two being septicemic plague and bubonic plague. The pneumonic form may occur following an initial bubonic or septicemic plague infection. It may also result from breathing in airborne droplets from another person or cat infected with pneumonic plague. The difference between the forms of plague is the location of infection; in pneumonic plague the infection is in the lungs, in bubonic plague the lymph nodes, and in septicemic plague within the blood. Diagnosis is by testing the blood, sputum, or fluid from a lymph node. While vaccines are being worked on, in most countries they are not yet commercially available. Prevention is by avoiding contact with infected rodents, people, or cats. It is recommended that those infected be isolated from others. Treatment of pneumonic plague is with antibiotics. Plague is present among rodents in Africa, the Americas, and Asia. Pneumonic plague is more serious and less common than bubonic plague. The total reported number of all types of plague in 2013 was 783. Untreated pneumonic plague has a mortality of nearly 100%. Some hypothesize that the pneumonic version of the plague was mainly responsible for the Black Death that resulted in approximately 50 million deaths in the 1300s. The most apparent symptom of pneumonic plague is coughing, often with hemoptysis (coughing up blood). With pneumonic plague, the first signs of illness are fever, headache, weakness and rapidly developing pneumonia with shortness of breath, chest pain, cough and sometimes bloody or watery sputum. The pneumonia progresses for two to four days and may cause respiratory failure and shock. Patients will die without early treatment, some within 36 hours.