Thanks Spencer,
Those links and the "Rescue With Casualties" post were really helpful.
You know, if Charlie is sick, you wouldn't know it from looking at him. He's always running around, getting into things, doing normal kitty things. His eyes are bright and his coat is shiny. I check his litter box several times a day to make sure everything is normal in that department.
I sure hope he's ok. He's such a little angel and I want him around for a long time!