Letter 1

Letter 1

Dear Dr. Pedersen,

I seem to have a FIP problem in my small home-based cattery. I read your excellent article “Understanding Feline Infectious Peritonitis” and I understand it better than I did before, but I still have lingering questions. My particular case may be of interest to you as there seems to be one horizontal (cat-to-cat transmission) in our case. I started my breeding program with two pure bred cats (Siberians) and bred them for 1 ½ years. The first three litters were healthy with no issues. I then acquired a second female from Russia and bred her with my male, and this is when the trouble began. I received a call with news that a kitten from this mating was diagnosed with dry FIP or intestinal lymphoma and had to be euthanized. As this was unfolding, my kitten from a different litter, (my sire and the new Russian Siberian girl), also became sickly with FIP-like symptoms. I received yet another call last night from a customer who has two kittens also from the same litter as this kitten I kept that is not well, with news that one of their kittens had developed what sounds like FIP symptoms and their vet had to euthanize. Lastly, another kitten I kept from my original sire and dam’s litter appears to be in good health except for an ulcer in the back of her mouth that is scheduled to be removed and biopsied. My cats are strictly indoors and share mutual space.

My question is if there is a test for my healthy cats to determine which cat could be the carrier and cease breeding this one, or is it necessary to start with all new cats? Any advice regarding my problem is most appreciated!

-Breeder, small home based cattery

Dear Ms xxxxxx.

It is not unusual to lose all or most of a litter from FIP. I suspect that the first kitten did not have lymphoma, but rather dry FIP involving the caecum and colon. This is a very specific form of the disease and resembles intestinal lymphoma. However one does not want to diagnose two different things when one will explain it and also GI lymphoma is not seen in young cats. The usual reason why a litter can be devastated with FIP is because they all share the same environment, genetics and history.

The virus that causes FIP is only spread from cat to cat in rare circumstances. Rather, the FIP virus is generated internally in each cat through the intermediary of feline enteric coronavirus (FECV) infection. FECV is ubiquitous among multi-cat environments and 40% or more of adult cats will shed the virus in their feces at any given time. Virtually all kittens are infected with FECV by 9 weeks of age and the infection is either unapparent or manifested by a transient diarrhea or loose stool. As you have read, the enteric virus must undergo at least three specific mutations to cause FIP, and two of these mutations are unique to each cat. When we do genetic analysis of the FIP viruses from littermates, we always find each FIP virus to be unique and therefore not spread directly from another cat. If there was direct cat-to-cat transmission the FIP viruses would be genetically identical. Although we cannot examine the viruses in each of these cats, the odds are that they each mutated to become an FIPV in different ways.

You have been subjected to what I call a “perfect storm,” where a lot of factors leading to FIP have come together at the worst possible time. Because they were littermates, they were all exposed to FECV at the same time and at the same level, they were genetically related, the exposure occurred at a similar age (the younger they are the more likely they will develop FIP as a consequence), and they are all exposed to similar external stresses that might affect their resistance. You can send feces from your older cats to IDEXX laboratories and confirm which of your cats are carrying the enteric coronavirus, but most likely a large proportion will be fecal shedders and the information will not prove helpful. This is no different than most catteries. Therefore, I suspect that other factors are also at play. The most likely is a genetic susceptibility and the recommendation in such a circumstance is not to breed these cats again, and if you do, not to each other. You also did not say how many cats and kittens you have in your cattery. The more you have, the higher the level of enteric coronavirus you will have in your cattery, and the more likely that you will periodically suffer FIP losses. I know that this is not want you want to hear, but this is my best reading of what has happened. Also, FIP is a strange disease and these perfect storms don’t happen often. It is common for such outbreaks to suddenly occur and just as suddenly disappear. You then fearfully wait for the next perfect storm, which can be right around the corner or years away. I have always said that “if you breed enough cats for long enough, you will experience FIP.” You have now had your experience with the disease. Good luck, Dr. Pedersen

P.S. would you allow us to use your story and my answers in our SOCK FIP website. We would delete names and alter the story a little. Other breeders suffer similar outbreaks and it would be nice to share them. Also, you should read the “Synopsis of FIP”, the updates on recent FIP research studies, and the 2008 paper on feline enteric coronavirus. – NCP

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