"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.

[vfrohloff]

I'm sorry you are having to go through this. I'm a bit surprised that your vet even bothered with these tests because they are pretty unreliable, there are lots of false positives and results can vary from one lab to another. FIP is not all that common, even though it is a serious disease when it occurs. FeVC on the other hand is pretty common but rarely translates into anything serious, the cat may get runny eyes and a sniffle but that's usually as far as it goes. I have 5 cats and none of them have ever been tested for FIP or FeCV. In fact, in all my years of owning cats (I've had dozens) I've never had one that developed FIP and most of them were strays whose background I didn't know. I do have all my cats vaccinated for FeCV though because it is more common and highly contagious. I have taken in a few cats over the years who had FeCV but because my others were vaccinated they never got it. Have your other cats been vaccinated? If so, ask your vet if they were vaccinated for FeCV, it's usually pretty routine. Until you find out, I would be changing clothes every time you come into contact with the kitten, just to be safe. I hope that helps, and as I said I wouldn't worry too much about FIP, especially since the tests are so unreliable. Good luck!

[adastra]

Thank you for your kind words! After doing a little 'homework' over the weekend, I was also surprised that the vet had ordered this test -- it's uncommon and unreliable!

Neither of our other two cats have been vaccinated against FeCV, but there is also a lot of controversy over that vaccine. All in all, FIP is really poorly understood at nearly every level (diagnostics, prevention, treatment, etc.). I've read page after page from the experts at Cornell, UC-Davis, and other places and feel no more certain about where to go from here! From Cornell, on the vaccine:
"The vaccine for FIP (Primucell© FIP, Pfizer Animal Health) has been shown in some studies to protect up to 50 to 75 percent of vaccinated cats, but it is not effective in cats previously exposed to FCoV. Also, veterinarians don't currently know how long immunity lasts, and some are concerned that the vaccine will make future testing ambiguous since the vaccine triggers antibody production against the virus."

One of my "reality checks" is that very few shelters or rescues test for FeCV exposure... even though their cats come from high-risk backgrounds. There's a good chance that our rescued cat Nukumi (now almost five) would have antibodies present because of all of her time spent with tons of other cats.

We've been changing clothes (shirt, pants, and shoes) between the kitten and the other cats... but it's just a regular old house and we're not taking showers a zillion times per day.

[vfrohloff]

I hope you don't mind, but I had to phone my vet for something else and I asked her about this. She said the vaccine for FeCV is pretty reliable and she gives it routinely unless people ask her not to. It is the FIP one that is questionable, and she offers it but doesn't give it as part of a "regular" vaccination. Since so little is known about FIP she is unsure as to how much protection it actually gives, and since FIP is not very common she doesn't usually bother with it. She also said that although the vaccine for FeCV is reliable, the tests to detect whether your cat has it or FIP are not very clear and she doesn't test for them as part of a normal blood panel unless the owner asks for it or she has reason to believe the cat has one of these 2 diseases.

[adastra]

Thank you!

Since our initial panic, we've done a ton of research and sought plenty of opinions. Hearing from vets has been a relief -- though none of them can make any guarantee that we won't end up with FIP in our household, the reality is definitely that this is not a "screening" for FIP and that it remains a very rare disease.

The most recent vaccine studies have shown 60-70% efficacy... but so little is understood about the disease and its transmission that they still can't draw ample conclusions. As these vaccines are really only for cats that have never been exposed to any feline coronavirus, I've yet to find a researcher that recommends them for cats that haven't been tested for FCoV exposure.

Anyway, thanks for asking your vet's opinion! I've spoken with three additional vets on the phone and consulted the research from the three top FIP study groups. All in all, we're really looking at infection rates much smaller than 1% unless you run a high-volume cat facility! I'm willing to accept a risk of ~0.06% that one of my cats could someday have FIP, which is what the statistics seemed to indicate.

Whew.