How did the black death spread from human to human?

The Black Death primarily spread through direct contact with an infected person or their bodily fluids. Here's how the disease was transmitted from human to human:

Respiratory Droplets: When an infected person coughs, sneezes, or speaks, respiratory droplets containing the bacteria Yersinia pestis are expelled into the air. These droplets can be inhaled by nearby individuals, allowing the bacteria to enter the respiratory system and cause an infection.

Contact with Infected Material: The bacteria Yersinia pestis could also be transmitted through contact with infected materials, such as clothing, bedding, or other personal belongings of an infected person. Touching or handling these materials and then touching the face, particularly the eyes, nose, or mouth, could facilitate the entry of the bacteria into the body.

Flea Bites: While respiratory droplets and contact with infected materials were the primary modes of transmission, fleas also played a significant role in the spread of the Black Death. Fleas that had fed on infected rodents or humans could carry the bacteria and transmit it to healthy individuals when they bit them. The bites of infected fleas introduced the bacteria directly into the bloodstream, leading to a rapid and severe infection.

Once the bacteria entered the body, it would multiply rapidly in the lymph nodes, causing the characteristic swelling known as buboes. The infection could then spread through the bloodstream to various organs, leading to fever, chills, internal bleeding, and organ failure. The mortality rate for individuals infected with the bubonic plague was extremely high, with death often occurring within a few days.

It's important to note that the Black Death primarily affected urban areas with dense populations, poor sanitation, and close living conditions, which facilitated the rapid transmission of the disease from person to person and from rodents to humans.