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How can pneumonic plague spread from one person to another?
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plague
Image depicting victims of the sixth biblical plague.
Pneumonic plague is highly infectious and can spread directly from one person to another through respiratory droplets expelled when an infected individual coughs or sneezes.1
Unlike bubonic plague, which is primarily transmitted via the bite of infected fleas, the pneumonic form involves extensive invasion of the lungs by the bacterium Yersinia pestis. Because the pathogen is present in the respiratory secretions of an infected person, it can be passed to others in close contact through the air.12
It is important to note that pneumonic plague is a severe and life-threatening condition that requires immediate medical intervention; without prompt antibiotic treatment, it is almost certainly fatal within three to four days.1