Did you know every time you touch your eyebrows, you come into contact with hundreds of thousands of mites? Your bed is infested with trillions of dust miotes living off your dead skin, etc? That's if you clean regularly, too.
20% of the weight of a 10 year old bed can be dead dust mites.
I can tell you from the smell of French tourist that their Mite count is probably in the billions and that is counting only their crotch.
They might not take a bath but you would never catch them picking their teeth.
However, they do like to take a whiz against any old wall whenever they feel like it. Especially in front of a young girl.