If you don't understand how the basic concept of washing your hands (which at the time was just splashing your hands in dirty water) stems from having a higher understanding better quality standards of living, like not sleeping with the farm animals for warmth, shitting in the street, or bathing in dirty water, all of which can cause rats, fleas, and ticks to rampage an area, then that's on you.

I can't teach you cause and effect of dealing with a long term systemic issue caused by a multitude of factors and variables.