The Black Plague, or Black Death, primarily spread through the bacterium Yersinia pestis , which is transmitted by fleas that infest rodents, especially black rats. Fleas would bite infected rodents, acquire the bacteria, and then transmit it to humans through bites when the rodents died and fleas sought new hosts. This flea-borne transmission was the main vector for the bubonic form of the plague
. The plague spread initially from Central Asia or the Crimea region, carried by fleas on black rats aboard ships, notably Genoese trading vessels, reaching Europe and the Mediterranean in the mid-14th century. Once ashore, the disease spread rapidly through human populations, not only via flea bites but also through pneumonic plague, which is transmitted person-to-person by infectious respiratory droplets. This form allowed the plague to spread quickly inland beyond the reach of flea vectors
. In summary, the Black Plague spread through:
- Flea bites from infected rodents to humans.
- Contact with infected animal tissues.
- Inhalation of respiratory droplets from pneumonic plague cases, enabling human-to-human transmission
This combination of flea-borne and airborne transmission facilitated the rapid and devastating spread of the Black Death across Europe, Asia, and parts of Africa in the 14th century.
