Pneumonic plague is the least common form of plague. Pneumonic plague is the most contagious form because it can spread from person to person in airborne droplets.
- 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 2 to 4 days and may cause respiratory failure and shock. Without early treatment, patients may die.