3 1/2 week old kitten dying from Feline infectious peritonitis

A stray cat I adopted ended up have a litter of 5 kittens. She is timid but was able to get her into a bathroom to provide her and kittens a safe place. After 2 weeks I noticed 1 kitten with labored breathing and rushed to the vet. They xrayed and said she had aspiration pneumonia and was best to put to sleep. Then now one of my almost 4 week kittens yesterday was lethargic, not eating and breathing heavy. This was the strongest and largest kitten and he was very active even the day before. I had to take to the emergency vet because it was after hours. The vet said she thinks it is FIP but cannot confirm this unless they run a bunch of tests (of course these tests and X-rays cost more at the 24 hour vet), and even then cannot confirm this virus only rule everything else out. Even then at this point the kitten may not pull through. We put the kitten to sleep. Was my favorite one .

I started researching on the Internet and it doesn't appear that FIP kills kittens that quickly. The mother is still nursing the other kittens and everyone else seems fine. Anyone else heard of this or had this happen? This vet thinks the first kitten also died to FIP.... Is everyone else going to be sick?

Also, the kittens mouth and pads on its paws were yellowish... She said this is a common sign on FIP. I almost think she selected this scenario of what was wrong because th amount of tests that would be involved. Anyone else have a kitten go downhill so quickly and it was FIP??

I'm so sorry for your losses.  FIP is a nasty disease, and it's true, there is no single test to diagnose it (except at autopsy...so you could request autopsies if you are inclined to know).  I've had a brush with it, and was actually just reading up more on it yesterday.  I came across this super informative site that will satisfy all the questions that I know will be going through your mind.

Rest assured, FIP itself is not contagious.  They believe it is all INDIVIDUAL mutations of the corona virus - not transmission of the mutated virus (FIP). Corona virus however is extremely transmissable - they'll all have it.  But most cats live fine with little to no symptoms.  My present kitten has corona virus - so my big cat will have it too.  From what I know, it is a bit unusual for a kitten so young to die from FIP - usually it strikes around 6months to a bit over a year.  They think stress is a big trigger for corona virus to mutate.

So anyway, here's the most knowledgable stuff I've read about it (and I booked a session with a Feline Specialist to get my head around it when I had my brush with FIP...all the stuff in this site lines up with what she says)

http://www.2ndchance.info/fip.htm

My best wishes for you and your kittens

 3.5 weeks seems  younger than usual to die of FIP.     And  this sure seems to have been caught,  mutated, incubated and progressed unusually fast    particularly  for the "dry" form of FIP  (,   and you did not mention that the kitten was swollen with fluid in the abdomen, like in the "wet" (effusive) FIP.  

The yellow discoloration ( called icterus or jaundice) is a sign of too much bilirubin in the blood,  and can be caused by plenty of other things besides FIP.   

The only way you would know for sure would have been to have them do a necropsy.

but I don't think it sounds so strikingly like FIP.  

  How is the mother?    I have heard of cases where the mother cat was infected not just with the common Feline Coronavirus,  but it had mutated to the FIP form,  and then kittens  were born with the FIP form of the virus. 

 I am sorry about these 2 poor kittens.    I'm afraid there is no way to answer whether they will all be sick because you don't even know what it was.  

The mother cat is fine. She is active, eating a lot, nursing. Doesn't appear ill at all.

The way I mentioned was the only way I have heard of the FIP virus directly transmitted.  but in that case  fdthe mom would have already had it when she gave birth.   Which does not seem likely o be the case here.. 

 I really am doubting this was FIP.

but it  is worrying not to know what it was ,  since maybe it was something else contagious.

   and if you did not get any testing done even basic blood chemistry and CBC ,  there is less to go by.  

 Is there any way that kitten could have got into something poisonous?    that could have caused the symptoms and is something that could come on quick.