The Hep C virus is a blood borne pathogen that can ONLY transmitted by
blood to blood contact.  It is not a STD, air borne or in body fluids.
If the ferret in question bit your husband and drew blood and then
immediately bit your son then I believe you would have a problem.
 
As for your ferret getting HepC, I don't know.  There would have to be
a open sore/cavity in your ferret's mouth for the virus to gain entry.
I don't think you have anything to worry about.  You may contact me off
list if you have any other questions.  Good luck to you.
 
Northern
[Posted in FML issue 4310]