What were the preconditions leading to the black death?

Answer 1

Some of the conditions that lead to the spread of the Black Death were poor sanitation and crowded conditions.

During the Middle Ages, when most of the cases of Black Death occurred, most people were ignorant of proper sanitation and the causes of the disease. Many people attributed the cause strictly to supernatural causes and would perform elaborate incantation ceremonies. They did not know about the existence of microorganisms.

Most Europeans of that time did not practice good sanitation. They would spread straw on their floors, which provided nests for rats. The rats carried the fleas which harbored the bubonic (black) plague organisms. It was also common practice for the commoners to bring their farm animals into their houses, which further compounded the problem.

Since many towns were small, which made them easier to fortify, the people lived closer together. This facilitated the spread of the disease.

Answer 2

Poor sanitation, little understanding of hygiene, widespread superstition, and broad ignorance of the nature, spread, and treatment of disease.