The black death was caused by infestation of mice and rats. Back then, they where dirty, it was called the dark ages. nobody were smart, they stopped cleaning, nobody knew how to read and write.
Fleas were the cause of it also.
People died, of Influenza, tuberculosis, no vaccinations, smallpox, dysentery, typhoid,
A lot of of kids died at a early age back then. Even the rich died.
Water was too dangerous to drink, because it was contaminated. Children, Believe it or not children, teens, and adults had to drink wine, they had no choice. I know its hard to believe and irresponsible, but its true.