You have probably heard of the coronavirus in cats and the fear of it developing into FIP. Many breeders are not concerned with coronavirus because it can be said impossible to rid a cattery of. Our own vet has stated several times that in order to control disease in any cattery, cats must live in laboratory-style facilities and that is when we question the lifestyle of those cats being bred. It is easy enough to ensure that kittens bred do not contract any infections in most cases by removing them from their mother when their immune system wanes as they start on solid foods. This is usually around 5 weeks old.
The coronaviruses are what we as humans have in the common cold. It is not something which concerns many breeders because it does not cause any symptoms or pain but in some cases the virus can mutate into a infection which is incurable so great care must be taken to manage a cattery with corona. In cats it is called the "Feline coronavirus" and there are many strains, similar to the cold.
How do cats get infected with coronavirus?
Coronavirus is probably one of the most common infection in cats, as with the human cold, since they are the same kind of virus. It is more likely to infect every cat in the household or cattery, like colds do in human households. There is an estimate that around 40 % of household pets have coronavirus and in multi-pet households or breeding catteries it is said that the infection rate is likely 100%. Cats ususally contract the virus again, through faeces. The virus sheds in the faeces and can survive in the environment for up to a few weeks but is very easily destroyed through disinfectants. You can see which disinfectant we use in our blog here. The virus once ingested affects the intestinal tract where it reproduces and replicates.
Testing for FCoV
Most clinics test at dilution rates of 1:25. If it's negative at 1:25 then you can 'assume' it truly is negative on that day. Not all labs test the same way however good labs with dilute a positive 1:25 result further until they get a negative result and this is called the 'end-point' titer. This will be seen as 1:400, 1:600, 1:3200 etc.
Some labs report 1:400 and above as positive. Lower titers are then reported as negative. The issue we then have here is that there are many cases of FIP reported in titers lower than 1:400 so you should try to find a lab that dilutes to 1:25.
Cats cycle up and down in titer levels therefore it can be hard to determine if a cat tested as negative, is truly negative. Cats can test different every week for 4 consecutive weeks although if you get a negative result for 4 consecutive week then it could be said that the cat truly is negative.
Virtually all cats in a multi-cat facility will be exposed to the feline coronavirus and they will likely not get FIP. Most breeders offer a guarantee to replace a cat which goes on to develop FIP.
My cat has corona - will it ever get rid of it? It is a hard answer to discern but the only way to find out is to test. Some cats shed the virus in their faeces repeatedly and will not stop shedding it. Others may shed the virus periodically and another group of cats may shed the virus altogether and no longer be infected - but get recurrent infections or have developed a strong immunity and be completely resistant to future infections, even potentially more dangerous strains. It can be said that a cat infected with corona may be more resistant to different or dangerous strains in a multi-cat environment and that it may even be beneficial for a cat to have come into contact with the virus to develop a form of immunity. Coronavirus tends to cause no symptoms at all but can cause very mild - almost undetectable diarrhoea.
My kitten has diarrhoea - is that coronavirus?
Kittens stomachs are very sensitive and diarrhoea so limiting a diagnosis of FCoV infection is never usually the case.
Does coronavirus cause FIP - and do they always get FIP?
It is hard to say what causes the mutation of the virus from corona into Feline Infectious Peritonitis. There is no known cause.
One way I would say to consider it, is similer to a cold and pneumonia in humans. Colds are often fought easily in health low-risk humans but on occasion, as a persons immune system is low due to factors such as stress or getting through a period of ill-health, they can inhale bacteria into their lungs and develop pneumonia. Pneumonia is usually developed straight after a cold or flu and by high-risk people.
Although the above is entirely unrelated to cats and coronavirus/FIP mutation it can be said that the same factors can attribute to the mutation of the disease. The coronavirus itself is usually fully-contained in the intestinal tract and the strains which cause these infections are called FECV which is Feline Enteric CoronaVirus.
Whilst the virus replicates itself in the instestine during the infection period it goes through various mutations. USually these are harmless but on occasion the virus can mutate into a different strain which causes a disease called Feline Infectious PEritonitis Virus FIPV. This is where it gets a bit more complicated.
The coronavirus replicates itself in the intestine-only but the strain developed called FIPV spreads through the body and replicates itself in the macrophages which is one of the major cells within the immune system of a cat. Some cats may be able to fight the virus well and display no signs although more liekly than not, the cat will develop what are called 'clinical signs of FIP'.
So can a cat get FIP without having the coronavirus?
No. The your cat has to have contracted the coronavirus first because the FIP virus strain is not shed in the faeces of cats infected with FIP, in most cases.
Remember your cat can develop an FIP strain of the FCoV but not actually display signs or be ill with FIP for a very long time. It is purely down to the health of your cats immune system and it's ability to fight the virus. We recommend pro-biotics, a stress-free environment and the lower end of numbers in a multi-cat household.
What are the clinical signs of FIP?
Clinical signs is a way of explaining the number of symptoms that are affecting a cats health and displaying sings of infection. The fact that FIP signs are very a-typical of any infection in a cat, it is therefore unlikely that your Vet will diagnose FIP on observations.
Your cat may not be very hungry, or up to much at all. In fact, you might just notice a difference in your cat but not be quite sure what has caused them to be acting differently. they may have a fever or be more sleepy than usual.
It is often that when a cat is developing FIP that it can take months to develop to a point where the cat is showing other signs of the disease. This is where bringing a cat from far afield or overseas is worth having an FIP guarantee to cover you.
Types of FIP
There are two main type of FIP and these are: Wet FIP / Effusive FIP and Dry FIP / Non-Effusive FIP. That is not to say that your cat will have one type of the disease. It can be a mixture of the two.
Wet or Effusive FIP
Wet FIP causes an accumulation of fluid within the abdominal cavity or chest cavity and this can be very distressing for the cat in any form and it's owners. The reason that the fluid accumulates is because the virus causes damage to the vasculitis and this causes the fluid to leak from the blood to the cavities. Abdomen cases relate to the name peritonitis because that refers to inflammation that occurs in the lining of the abdominal cavity. The fluid is usually clear or yellow due to the concentration of protein, however it is worth mentioning that other diseases, such as liver disease can cause the same fluid accumulation.
Dry or non-effusive FIP
As FIP causes inflammation, usually the lungs develop chronic problems due to the lesions which develop around the blood vessels. This can also affect other organs or areas within the body. This is known as 'pyogranulomatous' inflammation.
This kind of inflammation causes a whole host of neurological signs and in many cases the cat will not even be aware of this or be displaying signs of stress. The inflammation affects the eyes and the brain but it can also affect nearly all tissues in the cats body including their liver, kidney, lungs - even skin. It can be very difficult to diagnose FIP in the dry form and is usually done so through an autopsy after death.
The problem with FIP is that as soon as the first signs have been observed, they will get worse and there is not determining how long the cat will have left to live, since there is no cure. Surgeons can only try to ensure that the cat is comfortable (as possible) and on occasions where there is a sudden onset of the disease and a full assessment of the cat has been done via blood and case assessment, it may be suggested that the cat is euthanised. This can all happen very quickly.
It is thought that a cat with Dry FIP may fight the virus for longer if they have had a good immune response to the virus. Unfortunately they cannot prevent the inevitable replication of the virus and it's effusions long-term with the disease development.
What cats are most often affected with FIP?
Most cats with FIP are under the age of 2.
The majority of cases occur in kittens aged 4 months to 12 months old.
Most common in breeding colonies or multi-pet household.
Most common in crowded environments as stress is said to be a contributing factor to mutation and immune-suppression.
There is evidence that genetics can also be relevant in the susceptibility to the disease development but this is extremely complex.
How can FIP be diagnosed?
Your Vet should be experienced enough to know the initial signs and carry out further testing to try and come to a diagnosis as qiuck as possible. Unfortunately there is no specific test and the symptoms of FIP can often be related to a whole host of other diseases.
It can be said that the following procedures will be followed to help with diagnosis:
Signs - Cats are showing clinical signs compatible with FIP
Assessment - Cats are in a higher risk category (e.g., younger cats, colony cats, being mated etc.)
Tests - Typical changes are seen on routine blood tests - these may include
Lymphopenia (low numbers of lymphocytes, a type of white blood cell)
Neutrophilia (increased numbers of neutrophils, a type of white blood cell)
Elevated globulin concentrations (one of the major groups of proteins in the blood)
Elevated liver enzymes (eg, ALT, ALP)
Elevated bilirubin (and jaundice or yellowing of the gums and eyes)
Ultrasound and X-Rays to try and view fluid or scarring.
Sample fluid if found to check protein content.
Remember that none of the blood changes are specific to this disease but help to build an overall picture of the health of the cat and cause for the problem. You may need to repeat the tests to get different readings as it progresses.
With FIP the fluid invariably has a high protein content (greater than 35 g/l) and at least 50% of the proteins are globulins.
Other tests that can also sometimes be helpful include:
Further analysis of proteins in the blood (e.g., looking at globulin sub-types or measuring the protein acid-1-alpha glycoprotein [AGP])
Evaluation of a cerebrospinal fluid sample (the fluid that surround the brain and spinal cord) in cases where there are neurological signs
Can't they just check for antibodies?
Yes but as previously mentioned, the FIP strain is a mutation of the coronavirus, which most healthy cats will test positive for. The test can't tell the difference between the strains.
Confirming a diagnosis of FIP
As previously mentioned, the most common diagnosis is after the cat has passed away however there are options of carrying out a biopsy on the cat on the affected tissue area and this is because often a cat is too sick to under go any procedures. Usually they will be able to see the inflammation straight away and diagnose the damaged tissue through a technique called "immunohistochemistry".
Treatment for FIP
Once clinical signs of FIP develop, it is generally an incurable and fatal disease. Supportive and comforting treatment (e.g., anti-inflammatory drugs) may help relieve some signs and improve quality of life temporarily, but in most cases euthanasia is the most humane course of action to avoid suffering. There are some reports of cats responding to therapy with injectable interferon (recombinant feline interferon omega), but there is currently no evidence for this being genuinely effective.
Prevention of FIP
There is a vaccination for FIP but it is only available to kittens over 16 weeks of age and usually by this point kittens have come into contact with the virus. Usually it is redundant due to this fact. We keep all our kittens in a very secure and isolated environment to ensure that no viruses are spread to our kittens.
Reducing the risk in breeding households
FIP is least common in household pets. You can reduce the risk of FIP developing by obtaining cats from a source with a small number of cats, good husbandry and evidently happy cats (low stress environement).
In breeding establishments, getting rid of the coronavirus would be extremely difficult and since (as discussed above) cats may be safer through developing an immunity to the virus, a more reasonable approach is to introduce measures to reduce the risk of FIP occurring but recognising that on occasions, this may happen even in the best run catteries.
Good practice to minimise the risk of FIP:
Avoid keeping large groups of cats and having multiple litters of kittens at any one time
Keep cats in small groups (ideally no more than 2 - 3 cats in each group - this reduces the risk of endemic FCoV infection)
Have at least one litter box for every two cats, located in easy to clean and disinfect areas
Keep litterboxes away from food and water bowls, and clean/disinfectant them regularly (at least daily)
Avoid stress and maintain good hygiene and preventive healthcare for all cats
Wherever FIP occurs is a problem in a group of breeding cats:
Consider preferentially breeding from older cats, as these will less likely shed FCoV
Consider isolating queens just before they give birth and keeping the queen and kittens isolated from all other cats until the kittens are homed, as a means of reducing the risk of FCoV spread to kittens
Stop breeding from any queens or tom cats that repeatedly produce litters of kittens that develop FIP as they may be passing on FCoV infection or may be passing on genetic susceptibility to disease
Carefully review management and hygiene policies
If faced with an outbreak of FIP, stop all breeding for several months
Reducing the risk in rescue and rehoming facilities
Good hygiene and avoiding overcrowding are essential strategies for minimising the risk of FIP. Cats should ideally be housed individually, or if this is not possible, they should be kept in small stable groups. Litter boxes and cleaning/disinfection should be managed as in breeding households.