Feline Distemper
There is conflicting information about feline distemper. Many experts claim that ferrets are not susceptible to it. Nevertheless, there have been several reports of cases of feline distemper in ferrets.
None of these cases have been confirmed with diagnostic testing. It is, however, safe to assume that it is not a common occurrence. An inexpensive feline distemper vaccination could prove to be worthwhil insurance for your ferret. Check with your veterinarian for his / her recommendation.