Um, I've drastically oversimplified some of the stuff our vet told
us.  In particular, our vet does agree with you in that there is very little
concrete information vis-a-vis the relationship between what Toby died of
and FeLV, other than that Toby's syndrome was *very* similar to FeLV, and
that Toby did test positive for FeLV.  He did tell us that the test didn't
necessarily mean anything whatsoever, and that there did not appear to be
any concrete evidence that the ferret syndrome (whatever Toby died of)
is necessarily a FeLV-type retrovirus other than the similarity of symptoms.
He seemed somewhat reluctant to do FeLV tests in our other ferrets, but my
wife and sister-in-law were sufficiently concerned that doing FeLV tests
on the other ferrets would have at least *some* reassurance value.
 
I didn't intend for my posting to cause everyone to go out and get FeLV
tests for their ferrets, and if I didn't make the above clear in my
posting, I apologize.  I definately appear to have been incorrect in
stating conclusively that it *was* a retrovirus.
 
Regarding "rarity" - I really meant w.r.t. "absolute chance of catching it".
Not relative to other diseases.  And was really supposed to be relative
to ferrets only.
 
My posting shouldn't have been taken as any argument against having cats
vaccinated against FeLV - they should!  (We found out to our surprise that
my parents hadn't vacinated their cats against FeLV.  After this reminder,
they're getting it done as soon as they can)
 
Thank you for the clarifications.
 
I have some questions for you:
        - Do you have any information whatsover about how long it *might*
          take for a neoplasm to develop far enough for an outcome similar
          to Toby's?  (his spleen was larger than his liver when it ruptured)
          Even if purely conjectural, or for other animals, it
          might help our curiousity as to how long Toby might have had
          this problem.  (We wonder whether we mention this to the breeder
          and/or pet store where we got Toby.)
        - Purely out of curiousity - have you noticed, or seen mention
          of in the literature, any seeming correlation between "exotic-colour"
          ferrets and physiological anomalies?  Eg: Toby was a silver-mitt
          and he had two complete sets of anal-sac glands.  Or, in cats
          with confirmed FeLV that have been presumed to have caught it
          in their mother's womb, any indication of physiological anomalies?
        - Do you recommend rabies vaccinations for ferrets that are house-bound
          and don't meet other animals?
                                                                          
[Posted in FML 0022]