I suspect that oral hygiene and availability of food, materials for clothing and shelter, water, and routes for transport and travel, in addition to strategic consideration of the defensible site where the village was sited . . . along with knowledge of the bad guys and worries about the as-yet-unknown bad guys . . . affected:
What do we do, next?
Until the mobile phone showed up.
Rats, Lice, and History by Hans Zinsser (1934) provides some interesting insights on various plagues throughout history. And yes unsanitary conditions were often great contributors.