My sim got infected and she doesn't even live in Strangerville

Simply visiting Strangerville is harmless and from my experience won't trigger anything. But the pack comes with three pre-infected sims and soon as you interact with them, they may get ideas like visiting or inviting you. I think they can also get drafted as passersby and (if unemployed) for specific roles like food stall vendors, so it is easy to accidently interact with them.

The sims in question are .