Taken from a Cats Protection site:-
Feline infectious peritonitis (FIP) is a fatal disease, infecting nearly all cats who encounter it. It is caused by a viral infection (feline coronavirus - FCoV).
FIP is one of the most important viral infections of cats because cats that develop the disease cannot be treated effectively and the disease is almost always fatal. Fortunately the disease is quite rare.
Most cats simply become infected with feline coronavirus, shed FCoV for a month or two, mount an immune response, eliminate the virus and live happily ever after. However, for reasons that we don't yet fully understand, instead of clearing FCoV infection, an unfortunate few cats develop FIP.
FIP is more common in young cats, particularly in those below 1-2 years old (where the immune response is less well developed), in stressed cats, or those with concurrent disease. FIP is also more common in multi-cat households, Adoption Centres and catteries - where up to 10% or more of the cats can die from FIP.
How do cats catch FIP / FCoV?
The major source of infection is the faeces of infected cats. Uninfected cats become infected by sharing litter trays with infected cats.
At least 30 to 50% of pet cats are likely to have been exposed to FCoV and where large groups of cats are kept together, typically 80 to 100% of them will have been infected at some stage.
The second major route of infection is the unintentional exposure of uninfected cats to tiny particles of infected faeces on people’s shoes or clothing, hands, poop scoops, etc. The infected cat likely swallows the virus when grooming, or when particles of faeces contaminate their food.
FCoV is occasionally shed in the saliva - usually early on in the infection process, so sharing food bowls or inhaling sneezed droplets could possibly allow infection to spread. Close contact with infected cats, for example in mutual grooming, might, rarely, result in infection. At present, there is no evidence that FCoV is present in the tears or urine.
Feline coronavirus almost never crosses the placenta to the unborn kitten. Most kittens that become infected do so after the protective antibodies they receive in their mother’s milk have waned - usually when they are 5-7 weeks old.
There are 4 possible outcomes of exposure to FCoV infection:
1. The kitten or cat develops FIP (around 10% of infections).
2. The vast majority of cats shed FCoV for a while, develop antibodies, stop shedding FCoV and their antibody titre returns to zero. 58% of FCoV shedding lasts up to one month and 95% of virus shedding lasts less than 9 months.
3. The cat becomes a lifelong FCoV carrier (13% of infected cats). These cats shed FCoV continually in their faeces and most remain perfectly healthy although some develop chronic diarrhoea.
4. Resistant cats – around 4% of cats appear to be completely resistant to FCoV infection. They don’t shed the virus and they mount an almost undetectable antibody response.
How long does coronavirus survive in the environment?
FCoV is shed in the faeces. In natural circumstances, cats go outside to defaecate and bury their faeces, in which case the virus lasts hours to days (it survives slightly longer in freezing conditions). However, in domesticating the cat we have introduced litter trays and FCoV may survive for several days and possibly up to 7 weeks in dried up faeces in cat litter.
Which disinfectants kill FCoV?
Most disinfectants kill FCoV but Domestos and Milton are the first choice, at a dilution of 1:32, which is 1 part of disinfectant to 31 parts of water.
What are the clinical signs of FIP?
The name FIP is slightly misleading: FIP isn't inflammation of the peritoneum (the lining of the abdomen) it is a vasculitis (inflammation of the blood vessels). The clinical signs that the cat develops depend on which blood vessels are damaged and on which organ(s) the damaged blood vessels supply.
Approximately 50% of the cats with FIP develop the so-called "wet" (or "effusive") form. In "dry" ( or "non-effusive") FIP the clinical signs are more varied and this makes it difficult to diagnose.
Wet or effusive FIP
This is the acute form of the disease, where many blood vessels are severely damaged and fluid leaks out of them into the abdomen or the chest cavity. When the blood vessels in the abdomen are affected, the cat's tummy swells up with fluid called ascites. When the blood vessels in the thorax are damaged, fluid leaks into the chest - impairing the ability of the lungs to expand - and the cat shows difficulty breathing.
Dry or non-effusive FIP
Dry FIP is the more chronic form of the disease. In dry FIP, the cat often has vague clinical signs, such as going off his or her food, losing weight and the coat looking dull. Many cats with dry FIP become jaundiced (icteric), when you look inside the eyelid, it looks yellow. If the cat has a pale nose, you may notice that that looks yellow. Many cats with dry FIP get signs in their eyes: usually the iris (the coloured part of the eye around the pupil) changes colour, parts of it may appear brown.
The cat may bleed into the eye, or white precipitates appear on the cornea (the clear membrane on the front of the eye).
Around 12% of cats with non-effusive FIP develop neurological signs: often they become ataxic (wobbly and falling over when walking). They may have head tremors, fits, or their eyes may dart from side to side instead of being focussed.
However, all of these clinical signs can be caused by other, sometimes treatable, conditions, which is why accurate diagnosis is essential.
Any of the following clinical signs should alert you to the possibility of your cat developing FIP:
weight loss
recurring fevers (usually detected when your veterinary surgeon takes the cat's temperature)
going off food
the cat becomes even lazier than usual
sudden swelling of the abdomen
look closely at your cat's eyes regularly, watch for any change in colour of the iris (the coloured area of the cat's eye around the pupil) or any cloudiness, or bleeding
difficulty breathing (the cat breathing through his or her mouth)
if the cat has a fit or seizure
if the cat seems to lose balance, become clumsy
if the cat's personality changes
If you are a cat breeder, the following signs in your kittens should alert you to the possibility of FCoV being present in your cats:
kittens of uneven size in a litter
diarrhoea in kittens around 5-7 weeks of age
sneezing or discharge from the eyes
Remember that all of the clinical signs described above can occur due to other, curable, conditions, so take your cat to your veterinary surgeon to be checked if any of these signs occur and hope for the best.
Remember that 8 out of 10 cats whose samples were sent to laboratories for FIP diagnosis turned out not to have FIP at all.
How is FIP diagnosed ?
There is no simple test for FIP. Exposure to FCoV infection can be established by detecting antibodies to the virus in a blood sample (coronavirus serology). However, this does not allow distinction between past and current infection and cannot differentiate between strains of coronavirus. Thus, while very many cats have antibodies to the virus, very few of these cats ever develop disease.
More sophisticated tests are now available to detect the presence of virus in blood samples but, again, these tests cannot differentiate between different strains of coronavirus.
The only definite diagnosis requires examination of affected tissues, either through a biopsy or post mortem examination.
FCoV antibody tests
It is essential that your veterinary surgeon use a reliable FCoV antibody test such as the immunofluorescent antibody test used at the University of Glasgow Veterinary School. Not all tests are comparable with this - some other tests have high rates of false positives and false negatives.
Can FIP be treated ?
There is no cure for FIP. Once signs develop it is almost invariably fatal. Supportive therapy (e.g. nutritional support and anti-inflammatory drugs) may result in temporary improvement and can be used if the signs are not too severe. However, to date, no therapy has been shown to have long-term beneficial effects.
Can FIP be prevented ?
In multi-cat environments, minimising overcrowding (keeping cats in groups of six or less), ensuring the environment is kept clean (disinfecting with dilute household bleach where possible), minimising stress and other diseases will all help to reduce the risk of FIP developing. In other countries a vaccine is also available to help protect against FIP. However, this vaccine is not currently available in the UK and is certainly does not provide 100% protection against the disease.
Will my other cats develop FIP ?
If you have more than one cat it is important that any diagnosis of FIP is confirmed by tissue biopsy. If FIP is confirmed, there is inevitably a small risk that other in-contact cats may develop the disease. However, blood tests are not helpful in predicting whether a cat will develop disease. It should be remembered that most cats are able to develop a good immune response that prevents disease developing. Maintaining good health, preventing stress and avoiding the introduction of any new cats for several months are sensible precautions to minimise the risk of further cases of FIP.
