Oh wow, there must've been lots of infectious disease in such unsanitary conditions.
yes.... Which is why you wouldn't find those conditions anywhere in the medieval and earlier ages,
unless people were desperately destitute, or complete slobs. Both of which were very much looked down upon.
It's not until the height of the Plague Era that some idiots, spurred on by particular elements in the Church, come up with the idea that "a good stink" would hold the Wrath of God at bay.
Which included effectively eradicating the very ...lively... bath house culture in Europe. Because it was...well.. lively, and Offended the Pious.
Irony has it that "a good stink" did indeed keep the Plague at bay... If you used the right smell....
In France people noticed that stable hands, especially Horse Boys, never attracted the Plague.
And as ..."low status" a horses' smell, along with the job of caring for the beasties, was seen as, there soon developed a very frantic trade in used horse blankets and other... essence of horse derived articles...
Which was picked up in other areas as "it has to smell bad" .
Nowadays we know that the particular type of flea that used to spread the Plague
doesn't like the smell of horses. It's not one of their hosts, so they avoid it.
So the stable boys got exposed far less to Y. Pestis , because they lived in a
clean environment ( do try to suggest to a horse owner the stable the horse stays in shouldn't be clean... For Science... I dare you....
),
and the lads smelled Uninteresting to the flees.
One of those cases of Right Observation, Wrong Conclusion..
It also explains why Y.Pestis didn't move into Europe through the invasions of the Huns
much earlier, even though their origins lie in the Mongolian Steppes, where Y. Pestis is a Thing amongst rodents, and still is up to this day:
Those peeps
lived on horses, and smeling like one was a Manly Thing.. So they simply weren't carriers.
Same with the classic silk route: horses, mules, and camels.. Not Targets for the fleas.
It wasn't until there was more direct trade with the East that the bacteria came to Europe in bulk. Because we imported the rats directly along with the silk and spices... The "horse barrier" was gone..