FIP (Feline Infectious Peritonitis) is a fatal disease in both domestic and wild cat populations worldwide. Although seemingly rare in pet households, in breeder or shelter situations, it is more common. Many owners and breeders worldwide have felt the effects of this disease and the feeling of helplessness that goes with a diagnosis.

FIP is a mutation of the Feline Corona Virus (Fcov).

Simply put the Corona Virus is carried by most cats worldwide and it is a challenge to control in multi-population feline households such as those of breeders and rescues. It has been said that 90% of the domestic feline population have been exposed to this disease but it is relatively harmless resulting in few, treatable or no symptoms at all. Many have effectively shed the virus and have an immunity to it so of the approximate 90% exposed to FCoV only a small percentage are true carriers.  Symptoms include diarrhoea (usually mild in adults), mild respiratory symptoms, fever and depression, to name a few.

Feline coronavirus is fairly common among cats and is transmitted through the faeces of other infected cats or from breathing in contaminants such as spores. Feline infectious peritonitis is caused by mutation of certain strains of the coronavirus. While shedding, the virus is contagious but treatable and relatively easy to control, however once the virus mutates and becomes FIP, it attacks the white blood cells, which then carry the disease throughout the body causing havoc. Once the mutation occurs, your cat is no longer shedding coronavirus and is not contagious, however, FIP is almost in all cases, fatal.

Cats may shed the virus in their litter boxes, but with good hygiene practices, chance of contamination in pet homes will likely be low as it can be killed by bleach solutions effectively. The disease is a relatively fragile virus easily destroyed by the sun’s UV rays and as such, by placing the litter boxes outdoors in direct sunlight, this also helps to eliminate the virus. With regular corona titres one is able to determine who is shedding the virus so that they can be isolated and potentially eradicate the disease – however, the problem with titres is that they can lead to costly vet bills and no real understanding of the disease. It is unlikely that coronavirus can be eradicated completely in a multicat household, even with strict hygiene practices and the information provided by titres, as we do not run our homes in a laboratory setting.

The faecal titre test has to be done every 4 weeks for a period of 5 months and only once you get consistent negative titre readings can you say your cat is no longer a shedder. So a positive titre may be followed by a negative titre followed by another positive titre, which makes it a challenge to control in this manner.

What should breeders do to try and avoid FIP Mutation?

This is a difficult question because there is no way to avoid it completely. Most breeders have experienced FIP at least once in their breeding careers. The important thing is to exercise good protocols and husbandry practices to try and prevent the disease.

Firstly it is not possible for a pregnant female to transmit the disease to her unborn kittens and unlikely she will provide sufficient antibodies to combat the disease after 4 weeks of age (this is why kittens most often get sick during weaning stages as the maternal antibodies are wearing off). Contracting the disease is oral-fecal so once the kittens are born, sharing litter boxes with active shedding cats (which may very well be mum and this cannot be avoided in many cases), being groomed and cleaned by mum and the contagion entering the mouth or nose are the most common transmissions.

  1. Kittens should be kept separate from the general feline population as well as other queens and kittens in the breeders home, at least until their immune systems are better developed. The most important time is up to after the kittens are weaned as weaning stage between 3 and 8 weeks old is often when coronavirus will manifest in symptoms such as loose stool, fevers and lethargy. The breeder should provide separate litter boxes for kittens where possible.
  2. Stress in the breeders home should be kept to a minimum so for instance, overcrowding litters and cats can lead to an increase in the amount of contagion in the immediate environment, which can cause a huge amount of stress on the cats’ immune systems, which can then result in a higher chance of FIP Mutation. Highly strung breeds should be separated into smaller groups to avoid crowding stress.
  3. Litter box and general hygiene practices are crucial to eliminating corona spores from the environment and reducing contagion by killing as many spores possible. There will always be traces of the disease in the environment but the idea is to follow protocols to reduce the amount of spores responsible for contagion so that the cats’ immune systems can handle it and are not overloaded. This is also why having multiple litter boxes is important. To dilute the concentration of contagious particles.
  4. Owners and breeders should be careful when vaccinating in order to prevent overloading the immune system. Sometimes a reaction to a vaccine can be so strong that the coronavirus mutates following the reaction. It is important to vaccinate but follow your breeder’s protocol to avoid overdoing it.
  5. Give regular B12 injections to their cats to assist with red blood cell production – B12 is an essential vitamin that aids in digestion, prevents anemia and aids a healthy appetite. There is a fantastic article by the FIP Care Group that you can read on the many benefits of B12 –  READ THE ARTICLE

Even with all of the above in place, FIP may not be avoided!

FCoV does not = FIP

In fact on average only 4% of cats that contract coronavirus are likely to mutate to FIP. Stress and immunity are big factors so one needs to ensure a good healthy immune system and a stress free environment. FIP is often misdiagnosed and tests should be done to  always eliminate all the differentials before euthanasia.

What should you do if your vet suspects your cat has FIP?

Firstly, do not panic and do not accept a diagnosis without testing. Get in touch with the breeder immediately and not in an accusatory manner. This is as heartbreaking for the breeder as it is for you. You need to work together to confirm diagnosis and the steps to take. It is important to follow a process of elimination as many FIP suspected cats are misdiagnosed! Do not authorise euthanasia without a necropsy or if the cat’s symptoms are not severe, without appropriate differential testing to confirm likelihood of FIP. You will need to make the call to say goodbye to your beloved feline companion when the quality of her life is no longer viable, but it is always essential to do a necropsy to confirm this diagnosis 100% not only for you, but so the breeder can keep a record of such.

Differential Diagnosis table

(from the FIP Care Group)

If your cat has been diagnosed with FIP, your first step is to ensure you have the correct diagnosis. Why? Because errors are frequent. Getting a wrong diagnosis can be more devastating than no diagnosis at all. It is estimated that 80% of cats diagnosed with non-effusive FIP turn out to have another condition, usually treatable (based on Dr Diane Addie’s info in her book Feline Infectious Peritonitis and Coronavirus). The likelihood of error in the case of effusive (wet) FIP is lower but still varies widely depending on the cat’s age and breed. Making sure you have the correct diagnosis means talking to your vet. The number one source of WRONG diagnosis is a positive FCoV titre. 95% of cats are FCoV (Feline Coronavirus) carriers at one point or another. It does not mean they will develop FIP. Only 5% of them end up developing Feline Infectious Peritonitis. Also, be aware that there is NO DEFINITIVE TEST for FIP. So, if you are told your cat tested positive for FIP, chances are he or she tested positive for exposure to coronavirus. Positive FCoV titer DOES NOT MEAN your cat has FIP. FIP is a difficult diagnosis to reach, and is a process of exclusion, particularly with the dry (non-effusive) form.


Complete body fluids differential diagnosis table

(from the FIP Care Group)

The accumulation of fluid (or ascites) in the chest or abdominal cavities is characteristic of the effusive (wet) form of Feline Infectious Peritonitis. However, there are more than one type, and one reason for the presence of fluid in a cat’s body. The complete body fluids diagnosis table by Dr. Salih Sahir is one of the most detailed and thorough documents available. We recommend you print this useful table and take it to your veterinarian if your cat has been diagnosed with wet FIP based on the presence of fluid, but the fluid has not been examined and tested.


Once a diagnosis is reached and FIP is confirmed, discuss options with your cat’s breeder. The breeder may have policies such as ours where we recommend cats are on medical insurance to cover the vet bills for things such as FIP – make sure you do not only have accidental cover – as we do not cover vet bills once a kitten leaves our home. FIP will be covered by most pet insurance companies under illnesses. So that will give you peace of mind financially.

Most breeders will insist on a necropsy and vet report to confirm diagnosis. If the differentials have been completed, the breeder will work with your vet and with you to discuss options. Usually there is little hope for FIP diagnoses and the breeder will suggest euthanasia and necropsy to confirm. Once a necropsy is confirmed, some breeders will offer a replacement kitten, some will not and this will entirely depend on the breeder’s terms and guarantee. With regards to a replacement kitten, even if it is unrelated to the kitten diagnosed with FIP there is no way a breeder can guarantee that the replacement kitten will never contract FIP.  It can happen to any cat from the strongest and most robust of bloodlines. Purchasing a kitten from a different breeder may also not reduce the chances of a kitten contracting FIP. Notably as well, a kitten dying of FIP does not mean the breeder is unethical or unhygienic in any respect.

Most breeders will help support you emotionally during this time and although there is little hope, it is important to maintain that relationship. She may ask questions to determine if you are eligible for a replacement kitten so be open to this. There may be questions about the kitten’s environment at home, other animals, potential stressors, diet and medical history. This will all form part of guiding you in future to reduce stress factors, increase immune system efficacy and for record purposes for the breeder. If the breeder has multiple FIP cases from one combination of breeding lines, for instance, the breeder is then able to establish the cause and eliminate those lines from her breeding programme to reduce FIP cases in future. This pattern may only start to develop over a few years, however! If there is no pattern, and the case appears to be random, it is futile to blame the breeder for her part in the mutation as there is no way to know out of the thousands of triggers, what would have caused the mutation. Sometimes it just happens and your relationship with the breeder will be paramount to you receiving support and a potential replacement or with some breeders, a refund.

Check out the Feline Care Group files and read more about the myths associated with FIP, diagnoses, supportive care, new treatment protocols, supplements and more! There is so much misinformation out there so get it from a source that is reputable and accurate.

Thank you to Aurora Lambrecht for providing us with some insight into this misunderstood cat killer as well as to Dr Kurt de Cramer for his insight during the Hill’s Breeders Seminar held in October 2018!

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