Hi everyone. After we were forced to euthanize Molly a few weeks, we had
decided not to get any additional cats (we have four others), but of course
that resolution didn't last long, and we are fostering a new two-year-old
cat from a no-kill shelter. The cat was neutered, vaccinated, and tested
negative for feline leukemia at the beginning of July. (He had been picked
up by animal control as a stray and turned over to the no-kill shelter). My
other four cats are not vaccinated for feline leukemia since they are
strictly indoors, and I haven't brought any new cats into the house since
the last cat adoption 5 years ago.

So far, only one of my old cats was exposed briefly to the new cat. There
was a little growling, but then the both got in bed with my son and went to
sleep on opposite sides of him (not together). We provided the new foster
cat with his own food and water bowls and litter box. My old cat may have
eaten or drunk out of the bowls, but he was too fat to get into the new
covered litter box (he actually got stuck and my son had to rescue him).
Now, I am thinking that I may have put my old cat at unnecessary risk for
feline leukemia by allowing this exposure before having the foster cat
tested a second time and without having my old cat vaccinated against feline
leukemia.

The reason I am worried is that when we took the foster for a checkup today
(I found fleas - a very unpleasant surprise), the vet noted that he had bad
gingivitis. Since the foster is only two years old, this is unusual. It
could be caused by a bunch of different things (according to our vet), but
feline leukemia is one of the possibilities. The cat seems extremely
healthy. The vet tried to reassure us that the risk of feline leukemia
infection either in the foster cat or to our old cat is very low, but I'm
still really worried about. We are now going to keep the foster cat
separated from all our other cats until we have him retested for feline
leukemia next week and have all our other cats vaccinated.
1.  Am I overreacting at this point (since the cat did test negative for
feline leukemia in July and his gingivitis is obviously longstanding)?
2.  If by some rare chance the foster cat does test positive for feline
leukemia, will getting my other cat vaccinated protect him if he has already
been exposed?
3.  I have read some websites about feline leukemia and according to these
websites, a healthy adult cat who has never been vaccinated still has a
relatively low probability of contracting feline leukemia even if he is
exposed.  Does anyone know if this is true?

Thanks in advance.
Best regards,
---Cindy S.