One on One: A Conversation about FIP with Dr. Diane Addie


ImageDr. Diane Addie is famed for her research on feline infectious peritinitis (FIP). Here’s the content of an interview Dr. Addie conducted with Steve at the North American Veterinary Conference in 2005.

Dr. Diane Addie is a graduate of the University of Glasgow Veterinary School. After eight years in small animal practice, she returned to Glasgow University to work on feline coronavirus and feline infectious peritonitis (FIP) for her PhD.   She hosts a website dedicated to providing veterinary surgeons with information which is difficult to access otherwise, and for raising
funds for feline coronavirus research: She calls Dr. Niels Pedersen, legendary researcher from University of California, Davis her mentor. She and Pedersen are arguably the world’s leading FIP and coronavirus experts. Until April 2006 she was a senior lecturer in veterinary virology and Head of Diagnostic Virology at the University of Glasgow Veterinary School.

Steve sat down for a lengthy interview with Dr. Addie in the press room at the 2005 North American Veterinary Conference in Orlando, FL. Addie began by asking Steve if he wanted a cup a tea and proceeded to prepare it for him. She explained with sincerity that she would be very happy to one day be a restaurant server. She’s soft spoken, but clear in her convictions, hoping cat breeders’ goal will be for coronavirus-free catteries, and that the vaccine Primucell can and should be used.  Here’s their conversation:

Steve Dale:  I really think that once an owner experiences FIP there is no other disease like it, for cats or dogs,. People are impacted in a way that affects them for the rest of their lives.  First do you think that I am right? Second, what is it about this disease that is like no other?

Dr. Diane Addie: That’s an interesting point that I haven’t thought about and I haven’t followed human’s thoughts for the rest of their lives. I have certainly encountered people who are very passionate about things like FIV.  In the UK one lady has actually set up an FIV help line. I think it maybe a personality trait of the person who is very deeply caring.  I think partially the problem with FIP is the chronicity, that the animal can be ill for quite a long time so it can impact on the life on the person for quite a long time and there is sort of hope that comes up and gets destroyed, emotionally that’s really tough if you think you’ve got a cure and then you haven’t.  
S.D. Is this really the purring disease?

D. A. Very often people report that the cat that had FIP was more affectionate.  Perhaps these cats feel a little cold because they are slightly feverish so they want to come up to people more.  So I think very often the cat seems to be a nicer cat than other cats, so the bonding gets that much stronger and then the loss after that is devastating. 
S. D. Is it often the runt of litter?  I was told by one researcher that the cat most often who lands FIP is the tiniest, or a cat who has had a history of health issues as a young kitten.

D. A. Certainly the litters are of uneven sizes may well be already incubating FIP. 
S. D. Is it the runt of the litter cat we should most be concerned about?

D. A. I showed a slide of three littermates that I followed.  One was clearly runty, but the biggest cat got FIP first.  She got wet FIP which is the more acute form.  The runt lived to ten months before he died of FIP.  So when I did my stats I only analyzed uneven litter sizes.  I didn’t follow up specifically, whether it was the runt who developed FIP. I don’t know for sure.

S. D. See one researcher, in the States anyway, was reasonably concerned about runts or especially smaller cats more often likely to succumbing to FIP. And you’re saying you don’t know for sure. I say, ‘Talk to five people about FIP,’ you get five views.

D.A. That’s exactly right.

S. D. Here’s one of those questions. After my cat, Roxy, died of FIP, I wanted to set up management guidelines for shelters, breeders and ordinary cat homes – your average cat owner…all three groups. And one very well known researcher said "Don’t bother."  He believes if the cats are destined to get FIP, they are destined to get it and management to a great degree, doesn’t matter. I don’t want to take him out of context, but he’s really looking at genetics far more than management.  In other words if Mother Nature has pre-determined you’re an FIP cat, you are. What do you think?

D. A.  If I did not believe we could prevent this thing I don’t think I’d be fighting so hard.  And I really want to see this virus wiped off the face of the planet.  I don’t want any more cats ever to die of FIP. 
S. D. Well, I don’t to take anyone out of context. I’m sure any researcher working on the disease believes he or she can make a difference. But I also believe some researchers are far more interested in genetics being responsible, and figure if they can identify the gene, they can at least ultimately control FIP in pedigreed cats. And, then, perhaps understand more in general. Do you agree?

D. A. There is some truth to that but it is a very reductionist view of the world.  Einstein said … what did Einstein say? I’ve forgotten.

S. D. ‘Have a nice day? Clean your room? ‘

D. A. (Laughter)  After Isaac Newton, people said ‘There are laws of physics that mean this is a clockwork universe,’ and people begun to think that God had just wound up the clock and walked away and was no longer involved.  My personal belief is that He is very much involved day to day.  I am against the reductionist theory that life is no more than a series of chemical reactions, that we and cats are no more than a bunch of chemical reactions based on our genes.  I absolutely believe that if…well for example, I believe you can alter  the chain of events by prayer.  So if we can alter it by prayer, we can also alter it by treating cats well, feeding them well, preventing intercurrent diseases so that we totally maximize their chance to survive coronavirus infection if they are exposed to it.

An Italian study showed that when one of a series of cats that were naturally infected with coronavirus went down with FIP, the others all had a transient rise in acute phase proteins.Acute phase proteins are a sort of a crude response to a virus infection and the authors of the study think that that response perhaps correlated with survival. 

I believe that we are ingenious enough to make the cats survive,  to develop ways to outwit this virus.  How on earth are we, huge complex creatures, going to bow down to a puny wee thing that’s only got 30 kilobases of genetic code and say ‘Well that’s going to win. There’s nothing we can do about it.’  We should not give up and shrug our shoulders and just say ‘I don’t know…..  well if its going to happen it is going to happen.’  That seems to me very defeatist. 
S. D. But I’m confused…which does occur easily. I thought you were on board that there is some genetic component, or components, and/or a familial basis for FIP?  You are on the record, for example, saying that that in Persians you saw FIP over-represented.

D. A. Dr. Janet Foley showed that and she published that in Feline Practice, that Persians are more prone (to FIP).  You know you sort of feel well ‘you see more Persians getting it’ but than that is the most popular cat breed so but she showed it in a scientific way and I’ve looked at it myself.

S. D. And you also said FIP occurs more in pedigreed cats.  In America the overwhelming percentage of cats are domestic short hair.

D. A. Yeah statically…I mean you see it in domestic cats. If you were to look in a vet hospital database and you maybe found 50 domestic short hair cats with FIP and perhaps 50 or 60 purebred cats with FIP but statistically you should be finding ten times as many domestic cats and that is not what we are seeing. 

S. D. Is that genetic or is that lifestyle?

D. A. Primarily lifestyle. Because most domestic cats, who are living in just one and two cat households, and a lot purebred cats that are developing FIP are doing so within a short period of coming from the breeder.  Definitely where they are in a multi-cat environment where a lot of cats are shedding a lot of virus.

S. D. So doesn’t that make the line fuzzier as to whether it is really genetic or the conditions those cats are living under?

D. A. It would make it fuzzy but we are also seeing a lot of cats in Britain go through cat rescue shelters and undoubtedly a lot of the rescue shelters are having FIP problems too. 
S. D. That’s what I am saying. Name any breed, say the Maine Coon, are they maybe a little more likely to get FIP because of genetics, or is it the management situation that catteries in the U.S. typically have? Do you understand what I mean?

D. A. The easy answer to that is to cite the cheetah which went through a genetic bottleneck so the number of cheetahs in the world reduced terribly so they are genetically very, very similar and the corona virus wipes them out!  They are very prone to getting FIP.
S. D. We are getting bogged down on this. But to be clear, so you are suggesting there is a genetic component?

D. A. I am suggesting there is a genetic component as well as an environmental component.
S. D. Do you have any idea what that is? Or under what circumstances it occurs? Or how important of a component environment is?

D. A. I wish I did.
S. D. So, what recommendations would you make?  Where do you cut it off breeding? If the mom cat, the Queen, had FIP., do you cut it off there?  No more breeding for her? 

D. A. Well, if the Queen had FIP it’s not so much an issue. She’s dead.

S. D. (Laughs) Fine. Laugh at me. Bad example. Good point.  Let’s say one of the kittens has FIP.  Do you cut it off there, and this mom are then altered? Are those surviving kitties – the brothers and sisters spayed or neutered?  Do you wait for one more litter?  What’s the cut-off point? 

D. A. I think looking at mom is the wrong thing.  I think looking at the studs is more important because certainly in dogs and also in cats you are going to have stud cats that will father many more kittens than any queen could ever have.  They are in a far more risky position to propagate susceptibility to this disease

S. D. So when it happens once from one stud.  Do you cut him, sort of speak, and neuter him?

D. A. No.  (Laughs) I see. Cut him off?  I think if you have two or three litters where a kitten goes on to develop FIP from a stud cat, and that would be very, very worrying.
S. D. Now as a pet owner, if you want a pedigreed cat., is it appropriate to say to the breeder ‘Have you ever had FIP occur?’ If the breeder says ‘no,’ in my personal opinion the breeder is either new at breeding, lying, or has been darn lucky and should buy lottery tickets. What do you think?

D.A. I totally agree.  If a breeder admits to having had FIP, it is unfair to say ‘Oh my God you’ve had FIP occur I’m not going to get kittens from you!’ If you’ve got a breeder who is that honest, then you want to hang on to them and be respectful of that.  Also your next question would be ‘Are you early weaning and isolating? Would you be able to sell me a coronavirus negative kitten?’
S. D. What are those measures that you would recommend for breeders? 

D. A. Well the real luxury method would be to totally get rid of the corona virus from your household.

S. D. You must know there are critics out there who say ‘That’s fine Dr. Addie but in the real world that’s never going to happen?’  I’m sure you’ve been asked that before.  How do you respond?

D. A. I think that if you are too lazy to take the trouble to eradicate this from your cats than probably you shouldn’t be breeding.

S.D.  I don’t believe your friend Dr. Niels Pedersen is in quite the same place. Is it safe to say breeders aren’t going to work to try and achieve corona-free catteries in the U.S.? Or is it practical, even if they want to because of what you alluded to with new males coming in. And obviously, you can’t control corona in outdoor cats. You’ve heard all these arguments before. 

D. A. Well the situation has been very different in America from in Britain because until recently you haven’t had the same sort of quality tests available to you.  All I can say is that in Scotland the Birmans’ have already done it.  The Birman breeders have a culture of asking each other before they let their cats mate together, and ask “(have) you tested for corona virus?" 

If the answer is no, then you know, they are not going to use that stud, they are not going to buy a kitten from you.  And that has resulted in the Scottish Birmans being  coronavirus free.  I find that most households with less than ten cats will just spontaneously get rid of coronavirus.  If it is a fairly stable household of up to ten cats the virus will not be able to cycle and re-infect, and the cats will just get rid of it.

S. D. And how about bringing new studs?

D. A. Once breeders have gotten rid of the virus, they want to test the cat before they come in.  Now that has been a problem in this country (the U.S.) because the antibody testing wasn’t very reliable.  But you do now have Christian Leutenegger’s lab (at U.C. Davis), and you can actually test for the virus.  It is more laborious, you need more tests, to be sure that your cat really is negative but it is now feasible.

S. D. If  FIP does happen, should buyers’ get their money back?

D. A. In Britain already we’ve seen somebody sue a breeder under the Sale of Goods Act, and (the suit was) successful. When you buy something…if you buy a car, it should go, it should work, it should get you from A to B.  If you buy a kitten you can reasonably expect that kitten to last a few years to be the companion that you bought it for.

S. D. But do you think that it is reasonable for people to say:  ‘If I buy a cat from you I want a cat that will test negative for the corona virus.’  But really, even if it does test positive for the corona virus, odds are it well never get FIP. And it can test negative, I believe, and ultimately still come down with FIP – it’s possible.

D. A. You have a right to get a healthy kitten.  It’s not just FIP that these cats can get.  They can get chronic diarrhea, really intractable diarrhea.  It can damage the small intestine leaving them with sort of malabsorption syndrome.

S. D. But isn’t that the exception.  I always thought for most cats that have coronavirus, it’s pretty benign. In fact, so much so that the owners’ often are unaware – there are no discernable symptoms.

D. A. The majority of cats that get it (FCoV) are going to be perfectly all right.  But I think if you are paying several hundreds dollars for a cat you have the absolute right to demand that it is a coronavirus negative cat just as I’m quite sure you would expect it to be a feline leukemia virus negative cat or feline immunodeficiency virus negative.

We’ve shown that infection of kittens, and therefore FIP, can be prevented and that by early weaning, and then isolation, and most times you can prevent infection of a kitten. As a purchaser I think that it is your statutory right to receive a healthy cat. And I would encourage people to put pressure on breeders before they buy by asking is the coronavirus positive. We live in a capitalist world and it is consumer driven.  We are used to expecting our computers to at least to operate after we buy them. Why shouldn’t we expect our cats to live after we buy them?

S. D. And it’s so heartbreaking when they don’t.  And I ‘know’ people who have an FIP cat through the list serve which I participate on through Orion Foundation ( All right – let’s talk about management.

D. A. First of all, people need to assess how many cats they can realistically take good care of.  The number of cats they keep according to their husbandry practice so that they’re not having twenty, thirty or forty cats in an ordinary one or two bedroom household.  They should have a handful of cats, whatever number of cats they can handle. 

If they’ve got a cattery out back or whatever, that is a different kettle of fish.  But they need to be realistic about how many cats they can take care of, efficiently.  If they already have coronavirus present then simply separating the positives and negatives, and repeat testing every month or so will eliminate the virus.  It will show them if they have any carrier cats which can be then re-homed. Eventually, they can get a negative household.  Once they have a negative household, they can test all new cats prior to coming in. They can then demand negative kittens from other breeders they’re buying from; that is a totally reasonable thing to expect to do. 
S. D. Does the kind of litter or the brand of cat litter matter in transmission of the disease?

D. A. Some cat litters, for example Ever Clean or Cat Country, kill coronavirus in the laboratory, but unfortunately I haven’t been able to study how much of a difference the cat litter makes in real life. I would need to do a very large study where I would have infected households using virucidal cat litters and compared with non-virucidal brands. We’d also need to assess the importance of cat litter tracking on virus transmission.  .
S. D. Would you encourage a cat litter manufacturer to create a cat litter that has some sort of strong disinfectant in it?

D. A.  Most of them already do and I didn’t realize that when I set out to look at this. The nice thing about Cat Country is that it tracks less – which is was what drew it to my attention in the first place – and is environmentally friendly.  World’s Best cat litter is also great for not tracking and also has some activity against feline coronavirus.

The idea would to research whether the litter has any effect on viruses spreading from cat to cat. Does tracking or non-tracking really have an effect? I would think so. Could people transmit the virus to other cats by cleaning the box? Could you visit a shelter and then transmit the virus on your shoes?  And if there’s a strong anti-viral in the litter would it really matter – when billions of virus particles are shed in every gram of feces, even if you take out 99%, you are still left with millions of particles?

S. D. How do we determine whether the cats are corona virus positive or not?

D. A: I still ask for the antibody test.  I still ask for blood to be sent to myself in Britain.  A single sero negative result shows the cat is FCoV free.

S. D. What about in America?

D. A. The laboratory that I recommend at the moment is Dr Christian Leutenegger’s lab (at U.C. Davis) for real time reverse transcriptase PCR on the feces.

S. D. What about the Antech Eliza 7B Test?

D. A. I don’t want to get sued so I’m not going to answer that.

S. D. I think you just did answer. Is it a valuable test?

D. A. Isn’t it the fifth amendment you can use in this country? (Laughs) I know there are a lot of different 7b assays out there but if anyone is talking about looking for the deletion in the 7b gene then that is not accurate. 
S.D. So let’s try getting you to answer another way. Would you agree with Dr. Melissa Kennedy has published that the test can be useful, to a very small degree, but it is generally not a helpful test?

D.A. (She smiles).  Melissa’s a great scientist, but I would like to see more assessments done.

S. D. On these Internet lists people report various ratios for the titer tests, and the write panicked that their cats have FIP because according to such and such lab, there’s a high titer for the coronavirus. Or maybe they’re confident their cats don’t have FIP based on (titer) numbers that are very low if existent at all. Some vets swear by these titer ratios. Do these numbers really mean darn thing?

D. A.  They are only as good as the test that did the antibody test.  So the meaning will be completely different for everyone.  The antibody titers in our laboratory correlate with virus shedding.

S. D. But the majority of veterinarians in America right now, today, as of this moment, don’t send them out to Scotland.  Ok so do those titer ratios mean anything?

D. A. Because I’ve never worked in the States, all I can say is what I’ve heard: Dr Nancy Postorino Reeves took a bunch of samples, divided them all into five and sent them to five laboratories throughout the United States and got back five different answers. This is scary – that means those (results) would be completely meaningless.  The test is only as good as the laboratory you are sending it to.  And as a veterinarian, you want to be choosing a laboratory that publishes its results, that is using that antibody test in research. These tests need serious looking at; they really do. They need serious evaluation. 
S. D. But if they are not the gold standard right now why are we using them all together?

D. A. Because you always have.
S. D. Should we be using these antibody titer tests as a diagnostic tool?  Are the tests being overused? This ties in to what Dr. Niels Pedersen has said, he believes more cats die that are misdiagnosed based on vets taking the word for these tests as gospel or over inflating their value, than the number of cats who truly have FIP. If Dr. Niels is correct, this tragedy is far worse than the tragedy of FIP. This means cats – lots of kittens – are dying for no reason.

D. A. I totally agree with Niels on that.  I’ve heard him say that. He wishes he would never had anything to do with antibody testing (which he helped to craft) and that more cats die of the tests than ever died of the disease; it’s absolutely tragic.  And I have encountered that too.

I’ve had people phone up totally distraught saying “My veterinarian says my cats all have FIP.  She just put down half of them.  I have to take the other half in tonight to be euthanized.”  This was a real call –  I really got this call and I was distraught that these people were so uninformed.  That was why when I was talking about coronavirus eradication that awareness, knowledge, the propagation of knowledge is the single biggest tool that we’ve got and I thank you, Steve, for being instrumental in propagating the knowledge around the United States. 
S. D. Well, I thank you for what you’ve done – what you’re doing. Let’s say the cat really does have FIP.  It’s been diagnosed, and appropriately so.  What do you do next?  I have read everything from feline interferon to chicken soup.  What will work and under what circumstances and for which kind of FIP?  Maybe something works for dry but not wet FIP.  I don’t know.  I know you like the feline interferon but as you probably know there are veterinarians who say you might as well be using voodoo juice, including Dr. Pedersen. Besides, the stuff is expensive and very hard to get in the U.S.

D. A. Well in the UK a vial of five million units which would just be one injection for one cat will come in at about at 10-15 pounds would be about 30 dollars. And that would be given every other day to a cat with effusive (wet) FIP.  It is extraordinarily expensive and it may be that as more of it is produced the price will come down, I don’t know. It is very advanced recombinant technology.  However, cats with dry FIP get about a hundredth of a vial daily – so one vial lasts over three months, which is less expensive.

S. D. What was feline interferon first and is mostly used for?  It wasn’t developed for FIP in cats.

D. A. It wasn’t, no, and the first license for parvovirus in dogs. But in the UK we are using it for absolutely everything.  We’re going mad with it.  

S. D. All right. So is this going to a cure? Does it offer the cats remission? What is it that we’re talking about?

D. A. It’s been available in Japan far longer than anywhere else. And a Japanese vet presented a case study of 12 cats and he had success in four cats that were totally cured.  What was curious about that was that they were mostly middle aged and that they had effusive (wet) FIP which is the more acute form which was counterintuitive for me.  I would have expected cats to be more likely to die of that but he found that four got better, another two went into good remission – but that is just 12 cases. We’re needing to amass a lot more cases. We have no idea about any effect on virus shedding. It’s just too early.  We need a lot more data on it. 
S. D. Ok tomorrow your cat has FIP.  Do you try to treat that cat with feline interferon?

D.A.  Absolutely. She would get interferon straight away. 
S. D. Ok, what about what is currently being done in America to treat the cats with FIP?  Typically, there cats are given Prednisone.  Some say L-Lysine is supportive, and vitamins. Others say, you – in fact – don’t want to encourage the immune system quite that way and can actually speed the disease. Others say, it might was well be chicken soup, except to make the cat comfortable, there’s nothing to be done really. So, what do people do?

D. A. Prednisolone really does make a difference. I’ve also used thalidomide. Prednisolone extends life, brings globulin levels back down to normal, brings the alpha one acid glycoprotein levels back down to normal.  Use the multi-B-Vitamins, possibly vitamin C as well. 

Lysine is a total misunderstanding.  That is used for herpes virus not for coronavirus. It won’t have any effect on coronavirus at all.  Possibly zinc as an antioxidant should be considered.  We don’t actually don’t know what the receptor is for the type one feline coronavirus. For the type two it is called CD-13 and zinc has been used in humans with a cold and will shorten the duration of the cold but you do need to use it with amino acids.  And humans who took it reported a bad taste and not feeling too good and I would be worried that if you gave the cat zinc you may put them off food, which would not be a good idea at all.

S. D. This may sound wacky – but does petting the cat help?

D. A. Not so crazy. Stroking has been shown to release endorphins in the brain, making them a bit happier.  So go for it, make them purr; get them to purr somehow. 
S. D. Is FIP-an immune mediated disease?

D. A. Yes

S. D. Here’s what I did when I heard about SARS, and you tell me if I’m a lunatic or not. I called the National Institutes of Health just after a story was written in a New York papers, I think the Post, which had a headline that read ‘Cats Cause SARS.’  Of course, the story explained it was civet cats who may have been responsible. But the story never clarified – civet cats aren’t really felines at all; they’re members of the mongoose family. And the headline was misleading to say the least. The story did indicate it was a mutation of the corona virus that they believe started SARS.
    Anyway, I called the NIH thinking if we can better understand how the corona virus mutates in cats; I mean real felines – not civerts –  then we can understand how the corona virus mutates in other animals. Well, it turned out the honcho at the NIH that I spoke with totally thought what I said made some sense. And she encouraged me to pass the word to feline researchers, which I did.  But to my knowledge, researchers never jumped on it when the timing was good. Do you think there a potential link? If we learn about FIP might we learn more about SARS, and visa versa?

D. A. Yes. Indeed, I will be publishing soon about the lessons that I would like the SARS community to learn from the FIP community. I am very worried about the extrapolation of the antibody dependent enhancement (ADE) story into the SARS field because ADE  is very much a laboratory artifact.

S. D. What? Can you explain?

D. A. Antibody dependent enhancement is definitely a laboratory artifact and we’re already seeing papers saying  that putative SARS vaccine are causing ADE.  For example, there was a paper in Science saying that you should be very wary of SARS vaccines because it might make things worse because vaccination made things worse in FIP. And the whole antibody dependent enhancement story thing has resulted in underselling of Primucell (the Pfizer vaccine for FIP), the only vaccine that has actually gotten through the antibody dependent enhancement hurdles and gotten licensed for use in cats.  No doubt lots of very good vaccines have been chalked out simply because they were subjected to inappropriate challenge studies with the wrong strain of virus, far too much of it and given in the wrong way so I would warn the SARS community about that.

S. D. Do you think there could ever be a vaccine to prevent the coronavirus? In theory, of course, if there’s a vaccine to prevent the coronavirus, you stop FIP.

D. A. I think a vaccine could prevent FIP but won’t prevent virus shedding.

S. D. You said in your talk (at the North American Veterinary Conference) that if the cat already has the disease there is no point in vaccinating. 

D. A. Yes

S. D. What disease are you talking about?  Are you talking about the enteric coronavirus or FIP?

D. A. I’m talking about early FIP. 

S. D. How do you know if the cat doesn’t have early FIP?  Should we be vaccinating all of our cats as a protection? I don’t see why not.

D. A. I agree. I think the vaccine is a good idea.

S. D. All right, then, I’ll play the other side. Even if the vaccine is reasonably safe, and the early studies questioning safety are ruled out…All vaccines do inherently carry a risk of adverse reaction, even if it’s a minimal risk. It’s a matter of risk/benefit. If there is no benefit why vaccinate? And to vaccinate effectively for FIP as we do now, the way the vaccine works, would boosters be needed?

D. A. Well remember that a lot of the worry about vaccination is about the actual injection leading to fibrosarcomas. Primucell isn’t given by injection.  It’s given up the nose.  But certainly all cats going into rescue shelters should be vaccinated with Primucell. That is my personal opinion.
S. D. And how about your average person, average pet owner, with one or two cats?

D. A. If it were available in the UK I would be advising people there to use it. I do recommend it.

S. D. As you know the kittens are often times exposed to the coronavirus at an incredibly young age. What if the kitten’s already exposed to the coronavirus?  Is it going to do what it’s supposed to do because they are so young?  By the time the vaccine works it isn’t going to matter is it?    I’m not articulating it very well.

D. A. You’re very, very close.  For purebred cats the chances are they are going to be infected at five to six weeks of age so if you are coming in with a vaccine at four months old it is too late already.  

S.D. Exactly – so how can the vaccine be effective? How early can you give it, at four days…Of course not.

D. A. At four months old.  I know Dr. Johnny Hoskins looked at giving it at eight weeks old but I don’t think it worked particularly well.  The recommendations are four months old if my understanding is correct.

S. D. Then what is the point of vaccinating if you can’t give it to them that early? This is what I’m not understanding.

D. A. Well if you have an ordinary moggy and you have a kitten …..

S. D. An ordinary what?

D. A. Sorry, a domestic short hair cat.  It’s a British-ism. If you have an ordinary cat who hasn’t been exposed to corona virus and you vaccinate you increase that cat’s chance of surviving an encounter with coronavirus. It’s not a 100 percent protective but it is certainly better than nothing.

S. D. I’m still missing it. If you can’t vaccinate him at such a young age, would you like to see a vaccine available that’ll work with cats much younger? 

D. A. Sure, it would be nice to see a vaccine available.  It would have to work at five or six weeks of age.  I don’t think realistically that we are going to see that, but the point is that many non-purebred cats won’t be exposed until they’re older, so the vaccine is useful for them.  I would very much prefer to see that breeders don’t have coronavirus any more.  I wanted to see this thing wiped off the face of the planet.  It’s killed too many cats already. 

S. D. Right.  I agree with you.  Ok…let’s say you have one FIP cat. You want to protect your other cats from FIP. What can people do?  And how long should they wait if that was a single cat who died of FIP before you bring another kitten into you home? Again I’ve asked you 12 questions at once. Sorry –

D. A. That’s okay. If a cat has died of FIP and you want to get a new one and you’ve got no other cats let your house lie fallow for maybe one to two months. Steep the litter tray in disinfectant.  Vacuum absolutely everywhere and go and get a coronavirus negative kitten.  If you have other cats and you’ve lost a cat to FIP then minimize stress on the remaining cats as much as possible. Be really diligent about removing feces.

S. D. How about at least trashing all the litter boxes.

D. A. Sure. Good.

S. D. And you’ve said stress can be a remaining issue. Whenever there’s a household change cats can be stressed. And now, a cat has just died. Stressful. So, do you try to deal with easing the stress? Playing the remaining cats is something I suggest, and it’s good therapy for the people too.

D.A. Get a cat sitter to come in and watch over your cats when you’ve gone on holiday.  That sort of thing.  Don’t do any elective surgeries at this time. Play is fine, of course.

S. D. Now it seems to me that the cats that have FIP often have it after they get home from the vet’s office.  People sometimes think their cat has ‘caught’ FIP at the vet clinic. I will say, I’ve received several letters just like that.

D. A. Yes, I want to talk about that. That is a good question. Very often it is tempting to say, ‘my cat caught this virus in your surgery.’ That is not true. Usually, the FIP, especially wet FIP, will occur within one or two weeks of the surgery. Well, it’s an immune mediated disease so the cat has to have had time to make antibodies which will take about three weeks and then for the disease to develop. So, it has to be at least four weeks after the cat actually got infected.

S. D.  If a cat was vaccinated early on when it went negative the first time would it have prevented the cat from going positive again?

D. A. No.  The vaccine won’t prevent the cat getting re-infected and shedding virus, but it will prevent FIP. 
S. D. How long have you’ve been practicing medicine? And also where this interest in FIP came about, how it came about and how long ago? 
D. A.  I practiced for eight years in three small animal practices in the northeast of England.  Then I went back to university at 29 to do my Ph.D.  I wanted to work with Oswald Jarrett who was a feline virus specialist and I decided I wanted to do feline virology and I thought FeLV because that was his specialty.  But he had enough people already.  He asked if I would like to do dog infection with somebody else and I said ‘no.’ Then, he asked me if I would like to go work with his colleague who I won’t name and I said ‘no.’  And then he looked down at me from his tall height, he is a good foot taller than me, and he said ‘What about FIP?’ And I thought, ‘I’ve been pushing it here saying no so I better to say ‘yes.’’ Although I had only one page of notes on it at the time and didn’t really know what it was.  Well I had diagnosed one case but I wasn’t big on it but I just said ‘yes.’

S. D. That was when?

D. A. I guess that was in early 1987. 
S. D. Do you think we know more about FIP from 1987 than we do today?

D. A. Yes. Immensely more. Hugely more. 

S. D. So there’s hope?

D. A. There is a lot of hope.  Besides, I believe there is always hope.

To learn more about FIP and also Dr. Addie, check out her website
The website has specific goals:

1. To provide accurate and up to date information about feline coronavirus (FCoV), the cause of feline infectious peritonitis (FIP).
2. To provide a register of FCoV tested studs and queens so that enlightened cat breeders who know their cat’s FCoV status can contact each other. In the 1970s, Abysinnian cat breeders began testing for FeLV and eliminated it from their breed, other cat clubs followed suite. Now, at least in the UK, it is extremely rare for a pedigree kitten to be sold with FeLV, thanks to the dedicated testing of cat breeders. In Scotland, most Birman breeders are FCoV free. The war against coronavirus and FIP has begun.
3. To provide a register of FCoV kittens
4: To provide a register of study and queen cats of known blood type.
5: To provide information about feline blood groups and neonatal isoeythrolysis.
6. To raise urgently needed funds for FIP/FCoV research.

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Steve Dale is a certified animal behavior specialist who has been a trusted voice in the world of pet health for over 20 years. You have likely heard him on the radio, read him in print and online, and seen him speaking at events all over the world. His contributions to advancing pet wellness have earned him many an award and recognition around the globe.

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