Until now. Apparently we've been adopted. He's been out on the deck for three weeks. He flirts with Felix (and, what's more, she doesn't beat him up for it but tolerates him - the first time that's EVER happened with any other animal besides the snakes). He lets us pet him, he meows and walks through Neil's legs, and he's the cutest gray little guy.
We named him Spooky.
And yes, once he gets relaxed around us enough, there will be a trip to the vet so he can get checked out. For now we're washing hands after every pet and being very careful with him and Felix (although she did just get her shots, so it should be ok for her to fraternize)