His symptoms are sudden, huge weight loss, throwing up (saliva like material), overly tired, leisions on his back. That's about it. He had adrenal surgery last November. Somehow I figure this has to be tied to that.

I've heard about them catching colds, they can also get the flu from us and it can kill them. Whenever someone in the house is sick they are strictly forbidden from even looking at the ferrets until they are well again.

We don't tend to have fleas here. It gets too darn cold for them. So sorry, I have no experience to share in this regard.