Sveinbjorn Thordarson

Bubonic plague is primarily a disease of rodents. Infection most often occurs when a person is bitten by an infected rodent or a flea that has fed on an infected rodent. The bacteria multiply inside the flea, sticking together to form a plug that blocks its stomach and causes it to begin to starve. The flea then voraciously bites a host and continues to feed, even though it is unable to satisfy its hunger. During the feeding process, blood cannot flow into the blocked stomach, and consequently the flea vomits blood tainted with the bacteria back into the bite wound. The Bubonic plague bacterium then infects a new host, and the flea eventually dies from starvation.