Which disease is historically associated with fleas?

• A. Rabies
• B. Malaria
• C. Tularemia
• D. Plague

Answer: (D)

Plague is the disease historically linked to fleas because fleas—especially rat fleas—are the classic vectors that transmitted the Yersinia pestis bacterium from infected rodents to humans. In past outbreaks, rats carried fleas into homes and cities, and the fleas would bite humans, spreading the plague. The relationship is well known from events like the medieval Black Death, where flea bites from infected rats played a central role in widespread transmission. Fleas become more likely to transmit the bacteria after their gut is blocked by the bacterium, and their feces contaminate the bite site, facilitating infection.

Rabies is spread by bites from infected animals, not fleas. Malaria is transmitted by Anopheles mosquitoes, not fleas. Tularemia is mainly spread by ticks, flies, or direct contact with infected animals.