Since the feeding tube to its stomach was blocked, the flea was unable to satisfy its hunger. As a result, it continued to feed in a frenzy. During the feeding process, infected blood carrying the plague bacteria flowed into the human’s wound. The flea soon starved to death, but the plague bacteria now had a new host.
The pneumonic plague was transmitted through droplets sprayed from the lungs and mouth of an infected person. In these droplets were the bacteria that caused the plague. This bacteria entered the lungs through the windpipe and began to attack the lungs and throat.