The Black Death, a devastating pandemic that ravaged Europe in the mid-14th century, originated from a bacterium called Yersinia pestis. This bacterium is primarily found in rodents, particularly black rats, and is spread through flea bites.
The Cycle of Infection
- Rodents: Rats are the primary reservoir of Yersinia pestis. The bacteria live in their lymph nodes and are transmitted to fleas that feed on them.
- Fleas: Infected fleas carry the bacteria in their digestive system. When they bite humans, the bacteria enter the bloodstream through the flea's saliva.
- Humans: Humans can contract the plague through flea bites or direct contact with infected rodents.
Transmission Routes
The Black Death spread through various routes:
- Flea bites: This was the most common mode of transmission. Fleas infected with Yersinia pestis would bite humans, injecting the bacteria into their bloodstream.
- Direct contact: Humans could also contract the plague through direct contact with infected rodents or their bodily fluids.
- Airborne transmission: In rare cases, the plague could spread through the air via droplets from infected individuals, a condition known as pneumonic plague.
Geographic Origins
The Black Death likely originated in Central Asia, where it spread along trade routes to Europe. This is supported by historical records and genetic evidence tracing the bacterium's origins.
In summary, the Black Death originated from the bacterium Yersinia pestis, which is primarily found in rodents. The bacterium was transmitted to humans through flea bites and direct contact with infected animals.
