The bubonic plague was spread by which flea?

• A. Cat Flea
• B. Dog Flea
• C. Oriental Rat Flea
• D. Human Flea

Answer: (C)

Flea-borne spread of bubonic plague depends on which flea species acts as the main carrier. The Oriental rat flea, Xenopsylla cheopis, is the classic vector because it historically transmits Yersinia pestis from infected rats to humans. When this flea feeds on an infected rodent, the bacteria colonize its gut and can cause a blockage. As the flea becomes more voracious and starved for a meal, it regurgitates bacteria into the bite site, transmitting the infection to the person or animal it bites. Domestic fleas like the cat flea or dog flea are common pests but are not the primary culprits in most plague outbreaks. The human flea can carry the organism, but it isn’t the primary vector in the typical plague cycle centered on rats. So, the flea most associated with spreading bubonic plague is the Oriental rat flea.