As on the ruined human wretch, vermin parasites appear, so, these ruined shelters have bred a crowd of foul existence that crawls in and out of gaps in walls and boards
wretch (UNHAPPY PERSON)
a person who experiences something unpleasant:
a poor/miserable wretch
wretch (BAD PERSON)
noun [C] INFORMAL OR HUMOROUS
someone who is unpleasant or annoying:
Who's trampled on my flowers? I bet it was those two little wretches who live next door.
You wretch! You promised you'd give me a lift.