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Help The Fight Against FIP

The Fight Against The Most Deadly Cat Killer (FIP)

By: Val MacQueen & Dr Diane Addie

(Posted with explicit permission)

FIP Forum - A discussion forum for those who have a cat with FIP or have lost a cat to FIP.

Journalist Val MacQueen talks to Dr Diane Addie, PhD, BVMS, MRCVS, one of the world's foremost researchers into Feline Infectious Peritonitis

The diagnosis of Feline Infectious Peritonitis, or FIP, is a death sentence. There is no cure. Once FIP develops (from the coronavirus) in a cat's body, it kills swiftly and mercilessly. A cat diagnosed with dry FIP can sometimes live for two or three months and wet FIP (where the abdomen or lungs fill with fluid) kills almost immediately.

As my own vet told me when my own cat was diagnosed, The virus always wins. He gave her two to three days to live. Reeling from the shock, I allowed her palliative treatment from cortisone injections, but she declined so fast that I had to have her mercifully put to sleep only a few days later. She was dead within a week of diagnosis.

In these days of medical miracles, we laymen are stunned to encounter a killer for which there is no treatment and whose progress is predictably deadly and without hope. But the FIP virus is a tough nut to crack. One who knows only too well is Glasgow University's Dr Diane Addie, who has been dedicated to researching Feline Infectious Peritonitis for almost 16 years. I spoke to her just after she returned from a stint of exchanging information with American colleagues at the Cornell University Veterinary School (renowned for its feline medical research). It is worth noting here that Dr Addie does not use laboratory cats in her own research. I will address this later.

VMQ: First, I asked Dr Addie... We all know that a common cold is caused by a virus. We humans have been cursed with it for millennia yet, despite all the research, it has been impossible, to date, to find a cure for it. Bacteria can be fought with antibiotics. Why are viruses so much more difficult to battle?

DR ADDIE: Viruses have to live inside the cells, whereas most bacteria live outside cells. Thus an anti-viral drug would have to get inside the cell, whereas antibiotics don't have to. The other problem is the rate at which viruses can evolve and change - they may have as many generations in a few days as we've had since we learned to walk upright.

VMQ: I understand that FIP is an auto-immune disease, like AIDS or lupus. Is this right?

DR ADDIE: No, AIDS is not an auto-immune disease, it is a viral disease, like FIP. Lupus is an auto-immune disease. Auto-immune is different from immune-mediated: the former is where the immune system turns against your own body, immune-mediated is where the immune reaction to the virus, which SHOULD cure the cat, for some reason actually kills it.

VMQ: I have been told by vets that FIP is transferred by cats sharing food bowls, greeting one another nose-to-nose and breathing each other's air, and sharing litter trays. I believe you have narrowed it down from that?

DR ADDIE: FIP is spread through infected faeces, there is little danger in sharing food bowls or greeting each other.

VMQ: Is there an effective vaccine?

DR ADDIE: Not in the UK. There is an American vaccine, called Primucell, made by Pfizer. It's given by droplets up the nose and it does seriously reduce a cat's chances of developing FIP. Any cat about to be introduced into a multicat environment (like a boarding or rescue cattery) should, in my opinion, be vaccinated with Primucell if it is available in their country. (Editor's note: There are American veterinary pharmacology companies which sell various pet remedies and vaccines over the internet, but note that importing prescription only medicines is illegal.)

VMQ: Can a cat be born with natural immunity?

DR ADDIE: Probably not. Though we encounter some cats which I term 'resistant' - they don't get infected, they don't make immunofluorescent antibodies, they don't get FIP. We don't know why. I need funding to research these cats further. The Orion Foundation gave a donation to look at their FLAs. That's feline leucocyte antigen - which is part of the immune system which determines how a cat can handle a particular disease organism. But unfortunately the answer wasn't in the one FLA molecule we were examining. We need to look at others.

VMQ: If you have one cat who died of the disease, how long does your house remain infectious? How long should you wait before giving another cat a home?

DR ADDIE: At least a month. Possibly seven weeks.

VMQ: If you have more than one cat, and one dies of the disease, what should you do about your remaining cat(s)?

DR ADDIE: Avoid stressing the cats in any way. We are finding evidence that severe stress can tip a cat over into developing FIP. The exact determinant of FIP developing has never been fully established.

VMQ: Now to a terrible question and one cat owners often fear to ask: If you have a cat that shows no symptoms of the disease, yet you have it tested because its companion died of FIP, and the test comes back positive, is this an automatic death sentence?

DR ADDIE: Almost never! Ninety per cent of cats successfully survive being infected with this virus. However, a minority of cats unfortunately develop FIP, and these cats usually have a history of having been stressed. Once FIP develops, it is usually a death sentence for the cat.

VMQ: In some of your papers, you have talked about healthy cats shedding the virus? This means, they are infectious, but are slowly divesting themselves of the virus, I believe. If one is lucky enough to have a cat that does this, how long would it take it to be clear of it? I think you recommend having a second blood test about four months later to check the status?

DR ADDIE: Shedding is the term we use for excreting the virus, being infectious, in the faeces. There is no correlation between shedding and eliminating, or getting rid of, the virus. We would simply call that end of shedding.

Most cats recover in 2-3 months, then their antibodies go away after several more months. Some cats shed virus in their faeces for almost a year before eliminating the virus and several months later their antibody titre (that is, antibody titre is the amount of antibody present; it is the way we measure antibodies) falls to zero.

VMQ: You've mentioned that a FIP-positive cat could be tipped over into developing the disease by stress. If trying to alleviate any stress in the cat until it has eliminated the virus, would it be best to wait to introduce a new cat into the house for six months or so?

DR ADDIE: Once a cat's antibody titre is zero, you can stress him or her as much as you like! However, remember a couple of things - test that the new cat is coronavirus (FIP) free first of all, for the safety of both cats. Also, that many cats have herpesvirus infection, so that stressing them can trigger a herpes-shedding episode (which might appear as a bout of cat flu or conjunctivitis).

VMQ: Would you also advise not putting a cat in a boarding cattery during this period when you're hoping the cat doesn't tip over into FIP?

DR ADDIE: Definitely not - much too stressful. And sadly, research has shown that putting a cat into a rescue cattery can cause him or her to increase FcoV, (Feline coronavirus, the virus which causes FIP) shedding by a million-fold! Also, if you have a young cat known to be carrying the coronavirus, put off having them neutred until such time - hopefully - that they have eliminated the virus from their system.

VMQ: I saw somewhere else that there is a possibility that interferon may be helpful to cats with full blown FIP. What do you think of interferon treatment? I know it is terribly expensive and takes around three months to work, by which time the cat is normally dead.

DR ADDIE: The jury is still out on that one. There are anecdotal reports of interferon effecting a cure and in one Japanese study 4 cats of 12 recovered. However, we need a properly controlled clinical trial - which of course requires funding to do!

VMQ: Last time we talked, you mentioned good litter tray hygiene. Does this mean a cat can get re-infected by its own faeces?

DR ADDIE: Mainly it's about preventing transmission of the virus to other cats. But it is also possible that the cat re-infects himself.

VMQ: Just to clarify the point for us laymen, should one completely change the litter every time the cat leaves some faeces in it? Or can one just remove the faeces immediately and preserve the litter for use later?

DR ADDIE: No, but change the litter every two or three days and at that time give the tray a good disinfection with household bleach. I am looking for a cat litter manufacturer who will help me to develop a cat litter which will itself kill or contain the virus.

VMQ: What about urine?

DR ADDIE: No need to worry about urine!

VMQ: In a household where there is a dog and a cat, people may worry that their dog is at risk if their cat is unfortunate enough to develop FIP. Is there a concern?

DR ADDIE: The virus cannot leap species. A dog sharing a house with an infected cat cannot possibly catch FIP. And neither can you!

VMQ: If one feels one's cat might have been exposed to FIP, is there any reason to have a blood test, given that if the cat shows positive, there is no cure anyway?

DR ADDIE: A positive antibody tests shows only that the cat has been exposed, and a healthy cat with antibodies will usually remain healthy. I think the knowledge is valuable, because if the cat is at risk, one can reduce stress and reduce the cat's chances of developing FIP. You also know whether or not it's safe to introduce a new cat. If you don't test, you don't know.

VMQ: I understand the analysis of blood when testing for FIP is very complicated - and the tests devised at Glasgow University are the most dependable in the world. Is this correct?

DR ADDIE: Our tests are envied by others the world over as being very reliable.

VMQ: Dr Addie, I know that for your research, you refuse to use laboratory cats (meaning, I think, that you do not infect healthy cats in order to study the progress of the disease). Most cat owners would heartily approve and be most grateful to you, but can you tell us how you study the disease without subjecting laboratory cats to it?

DR ADDIE: My research relies entirely on samples I receive from naturally infected cats. Their humans and vets send me their faeces and from time to time their blood samples. When, in the course of time, they die, they also kindly send me their bodies for post mortem.

This research has overturned 40 years of research based on laboratory strains of feline coronavirus being injected into laboratory cats.

Here are some examples: It was believed that there were two feline coronaviruses, one that only caused diarrhoea, one that caused FIP: Not true - they can all cause FIP.

It was believed that cats with FIP no longer shed virus: not true, they do! It was believed that a cat was more likely to get FIP the second time he met the virus. Not true. It's more likely the first time. It was believed that cats only shed FCoV for a couple of weeks: not true, they shed it for months.

VMQ: It would seem that you're saying that using purposely infected laboratory cats to study the disease was actually counter productive and led scientists down the wrong path entirely?

DR ADDIE: Absolutely!

VMQ: Dr. Addie, thank you so much for taking the time to explain this hateful killer to cat owners who have been starved of helpful information on this subject.

DR ADDIE: Thank you for the interview!

Dr Addie's research is expensive. Glasgow University has provided facilities and funding for 16 years, but she needs additional funds to carry on her research and buy the expensive chemicals she needs. She also needs to be able to pay a modest salary to a qualified research assistant or PhD candidate. If you would like to make a contribution, however small to her work in combatting FIP, you can visit her website at

If you wish to make your donation in loving memory of a cat who died of FIP (or any other cat), let her know and she will record your pet's name on her website.

If you wish to make a donation by mail: Make your cheque or money order payable to: University of Glasgow Finance Committee Account - Accompany it with a short note directing that the money is to be used for FIP Research. Send your cheque and note to:

Dr Diane D. Addie
Dept. Veterinary Pathology
University of Glasgow Veterinary School
Bearsden Road
G61 1QH
(United Kingdom)

For "electronic transfers/standing orders" please see or write via snail mail to Dr Diane Addie at the above address.

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