When our first cat (Dingo) was run over we brought her inside for the night before burying her. We ought to have known better - you could see the fleas leaping off her even then. We spent the next few months with flea powder along every skirting board, and a constant smell and irritation from it. Oh, and flea bites: cat fleas can't live on humans, but you have to give them credit for trying.
Cat fleas don't live on anything, they lurk in carpets etc. (Think claws!)
I meant live on as in bite and drink the blood of: the do bite and drink, but I don't think it does them much good. But by the time they've found that out your legs are all over lumps and itching to buggery.