"Mildly positive" FECV/FIP titer result - where do we go from here?

[adastra]

On December 6, 2006, we adopted a 9 month old kitten. The little guy has had quite a wild life story -- his pregnant mother was rescued off the streets of Baghdad in February. He and his six littermates received medical treatment in Bahrain and finally came to the US for adoption this month. He was neutered and all of his vaccinations were up to date when we got him. We took him to our vet on December 7 to get him looked over and a few things done (deworming, basic tests), and we asked to have him tested for FIV and FeLV. Our vet talked us into adding FECV/FIP and toxoplasmosis to the panel. We planned on keeping him quarantined from our other two cats until we had negative test results in hand.

Today, we got a phone call -- the new kitten has tested negative for FIV, FeLV, and toxoplasmosis, but the results were what the vet called "mildly positive" for FECV/FIP. She told us that the serological test came up "positive" at one dilution, but then "negative" at another dilution. She suggested that we continue our quarantine for three more weeks, then get him tested again.

I knew nothing about FIP before today except the absolute basics, and now I've read several dozen pages written by vets and cat enthusiasts alike. And I feel like I have more questions than answers! So I'm hoping that some of the members here may offer some insight and ideas.

- My reading seems to indicate that these serological tests aren't straightforward, so how should I interpret these results? I've read that "positive" isn't always positive, and "negative" isn't always negative. As a screening test, this seems to be really confusing -- since so many cats are exposed to FECV, it seems like many cats (and especially most rescued cats) would have some "positive" result.

- We've been quarantining the kitten in one room with no contact with the other two cats. While we wash our hands diligently after contact, we don't always change all of our clothes. Is this enough? What should we be doing to further prevent infection? There is no sharing of supplies, but I am worried about the ability of the virus to live on bits of litter or our clothing/shoes.

- I am really confused about all of this... the kitten is wonderful, and it seems like his chances of developing or transmitting FIP are very low. But his test result indicates that he's at least been exposed to some coronaviruses. Is it safe for us to keep him around? He's already been in our home for 5 days, and undoubtedly there has been some contamination of the house through contact with our skin and clothing.

I didn't expect to get the FECV test when I entered the vet last week, and neither of our existing cats have ever been screened for FECV -- even though one of them is rescue from a higher-risk population. The serological test seems really unreliable as a screening test. I'm somewhat panicked, while the other part of me says that the rates of infection are still very low. Should I panic? Where should we go from here?

Thanks in advance.