Hey there. I'm sorry it's taken me so long to reply. Like you, I did some research and came across two sites containing a lot of questions with one just like yours. Scroll down to the bottom of my post for that answer. I lost my entire post to you when I closed the tab I was working out of. THIS site below goes into a lot of detail. Keep scrolling...and scrolling...for the second site and the shorter answer. I posted both since one can't have too much info, plus, other members may come along and read this some day.
FIP is not a contagious disease!
If your family includes cats or you know someone who lives with cats, please read this. I’m wandering back to the side of western medicine but this is a topic dear to my heart.
When I was working at the shelter I once got a voice mail from a client who had adopted a cat from us who came down with FIP and died. She was calling because she was angry that we had not tested for it and mentioned that her vet was recommending she euthanize her other two cats because they had been exposed and would most certainly come down with it and die. Of course I couldn’t get a hold of her and two of us spent the rest of the day frantically trying to reach her before she killed her two other cats. Luckily we did reach her in time.
FIP or Feline Infectious Peritonitis is one of the most misunderstood diseases in veterinary medicine. It is not contagious but it is a mutation of a contagious disease. It can not be diagnosed in a living cat yet there is a “FIP test”. There is a vaccine but it doesn’t work in most cats and there is some thought that it can actually help to induce FIP.
So let’s start at the beginning.
There is a virus in cats called Feline Coronavirus. This virus usually doesn’t cause illness or if it does just a little diarrhea or intestinal inflammation. It targets only gut cells. It is very common. Up to 80% of cats have been exposed to it and show an antibody titer. In multiple cat households and shelters and catteries up to 100% of cats have been exposed to it.
Sometimes for reasons that we do not know this virus mutates or changes into FIP, kind of like what happened to the Gremlins when they got wet. We think it is related to a weak immune system but we aren’t sure. FIP can attack any cells in the body by working through the white blood cells and it does, causing many symptoms such as a bloated and fluid filled abdomen, diarrhea, vomiting, a fever, lethargy, poor appetite, problems breathing and sometimes brain inflammation. Almost all cats with FIP die.
Occasionally two cats from the same household die of FIP. We used to think one had caught FIP from the other. However recently when researchers have studied where the mutation is in the virus they have found that the mutation will be different in each cat.
What does this mean?
It means that each mutation happened independently within that cat’s body. If they were passing the mutated FIP virus the mutation would be the same in each animal. This means that the FIP virus is not being passed once it mutates and is not contagious.
Why are cats is multiple cat households more likely to get FIP then?
Multiple cat households have a higher rate of coronavirus in them. The more coronavirus shed in a cat’s feces and picked up by other cats, the greater the chance there is for a mutation to FIP.
So how does a vet test for FIP?
There is a titer test called the FIP test. The only problem is that it tests for coronavirus not for FIP. Usually cats with FIP will have a high coronavirus titer but not always. And many cats without FIP will have a high titer. So a positive “FIP test” may point towards a diagnosis of FIP but also may not.
If a cat comes in with fluid in its abdomen which is common in FIP cats, the best test is a protein ratio run on the abdominal fluid. Most vets will also run bloodwork to test protein levels.
A high protein level in abdominal fluid with a low albumin/globulin (two proteins we look at) ratio with a high globulin level on bloodwork, and a high FIP/corona titer (positive FIP test) usually point towards FIP. That is the closest we can come. And many cats with FIP do not have all the above.
So why is there a vaccine if this is not a contagious disease?
The short answer is because we used to think it was. The FIP vaccine will work to prevent coronavirus in about 60-80% of the 20% of cats that have not been exposed to coronavirus ever. Or about 12-16% of cats. It will not work if cats have been exposed to coronavirus. In addition there is some thought that if the cat has coronavirus in its body the vaccine could induce that coronavirus to mutate to FIP. So the vaccine works in 12-16% of cats but may actually induce disease in the ones it doesn’t work for. Hmmm. Not very good odds if you ask me.
There is no good treatment for FIP beyond supportive care and most cats with it will die within a year or often times much less. In multiple cat households cleanliness, especially of litter boxes, can help cut down on the level of coronavirus, which helps prevent FIP.
Here is another answer I found at stopfip.org. It's much shorter and to the point. And the answer I wrote to begin with, but screwed up, and lost it. Anyway, here it is...
"A cat in my house died of FIP and I have other cats. I am worried that they will get FIP. What do I do now?
There is not a lot you can do; by the time one cat is sick, the remaining cats have already been exposed to the same FECV. Fortunately, cats that have FIP do not usually shed the FIPV from their bodies. If they do shed virus, it is of the FECV type. If the cat that died is not a full-sib littermate of any of the remaining cats and this is a typical home with 2-6 cats, the chances of any other cats dying of FIP are very remote."
Again, my heart goes out to you and the loss of your dear kitten. You said in your post it was approximately 2wks since you put Kitty down. I hope your other kitties are okay. From reading the above, it sounds positive.
Please let us know how your other kitties are~
I love The Rainbow Bridge. I love sharing too, even if you know it. Here it is. I hope it brings you comfort...
Just this side of heaven is a place called Rainbow Bridge.
When an animal dies that has been especially close to someone here, that pet goes to Rainbow Bridge.
There are meadows and hills for all of our special friends so they can run and play together.
There is plenty of food, water and sunshine, and our friends are warm and comfortable.
All the animals who had been ill and old are restored to health and vigor; those who were hurt or maimed are made whole and strong again, just as we remember them in our dreams of days and times gone by.
The animals are happy and content, except for one small thing; they each miss someone very special to them, who had to be left behind.
They all run and play together, but the day comes when one suddenly stops and looks into the distance. His bright eyes are intent; His eager body quivers. Suddenly he begins to run from the group, flying over the green grass, his legs carrying him faster and faster.
You have been spotted, and when you and your special friend finally meet, you cling together in joyous reunion, never to be parted again. The happy kisses rain upon your face; your hands again caress the beloved head, and you look once more into the trusting eyes of your pet, so long gone from your life but never absent from your heart.
Then you cross Rainbow Bridge together....