For an overview of ferret illnesses this site is much better than many
sites of its kind:
http://www.geocities.com/Heartland/Park/5295/ferret.html
 
Sadly, the person, Mr. Manosh Sanyathitiseree, who created the site
passed away a couple of years ago.  He did a fabulous job in creating
this resource.  Some things are out of date, but that is to be expected.
It's more inclusive and better written, though, than many of the lab
sites I looked at for the zoonoses question.
 
Here is the zoonotic disease section of that site:
http://www.geocities.com/Heartland/Park/5295/ferret.html#zoo
[Posted in FML issue 4600]