How did the Black Death travel to Europe and then continue to spread throughout the continent?

Explanation:

Bubonic Plague, also is known as the Black Death, originated from Asia, most likely China, India, and Persia. In October of 1347. it arrived in Italy with trading ships from Asia; their goods were very prized at the time, and the trade was greatly developed with these countries across all European countries.

The black death quickly continued to spread around Europe. The quick and easy spreading happened partly because of the trade, but more importantly because of the rats. It has been proven that rats and fleas can carry the disease, and many people got it from the bites of these creatures. The hygiene wasn’t developed at the time as it is today, and pests were everywhere on the ships and in the streets. Because it was a highly infectious disease, it quickly spread over the whole continent of Europe, resulting in million deaths.

worldwide, 780 million people do not have access to an improved water source. an estimated 2.5 billion people lack access to improved sanitation (more than 35% of the world's population)