FIP is caused by a coronavirus, that has mutated from a harmless intestinal virus of cats called the
feline enteric coronavirus (FECV). It is not known why the virus mutates from the harmless FECV (it can cause a mild intestinal
upset) to the pathogenic FIP.
Risk factors for this disease are multiple cat households, the presence of normal cats that shed coronavirus,
and the development of FIP susceptible cats in the general cat population. The continual infection and reinfection of cats
with coronavirus in multiple cat households increases the chance of an individual cat developing FIP. Any cat infected with
a corona virus has the potential of developing FIP. To give you some perspective on the current situation, 30% of household
cats and up to 90% of cattery cats carry the coronavirus.
Multiple cat households might be more susceptible due to increased stress, crowding, poor sanitation,
parasites, and other diseases like the FeLV and the FIV.
Cats can spread the coronavirus in their nasal and oral secretions, along with the feces. Even though
the virus can remain infective in the environment (contaminated feeding utensils, etc.,), it is easily destroyed by routine
This virus poses no health risk for people.
Within 24 hours of ingestion the virus spreads from the tonsils to the intestines. Within 2 weeks it
has spread to the large intestine, intestinal lymph nodes, and the liver. From there it can spread to any other body organ.
Cats that do not produce a full antibody response to the virus will end up with fluid buildup within body cavities, usually
the chest or abdomen. Cats that develop a full immune response to the virus do not get this disease, although they can harbor
a latent version of the virus for a period of time. The are immune, but carry the pathogenic version of the coronavirus, so
they can potentially spread it to other cats. If they become immunocompromised for some reason (stress, drugs, crowding, parasites,
other disease like kidney disease ) their infection can be reactivated.
This disease has two major manifestations. The first is called the "dry form". In the dry form the
white blood cells are involved, and cause an inflammatory reaction to the internal organs. These organs do not function normally
because of this inflammation, and eventually will fail as the disease progresses.
The other manifestation of this disease is called the "wet form", and is where the original name of
"peritonitis" (inflammation of the lining of the abdominal cavity) came from. It is called this because fluid accumulates
in the abdomen or the chest. The fluid that appears in the wet form is straw colored to yellow in appearance, and has a relatively
high protein content. The fluid originates from small blood vessels that have been affected by the immune systems response
to the virus. This immune response damages these blood vessels, causing them to leak fluid into the abdominal cavity usually,
or thoracic cavity less often.
Cats that already have FeLV are more susceptible to the FIP virus. It has been found that Persian and
Birman cats may have a susceptibility to the FIP virus.
Initially there are no or minimal symptoms after exposure. Some cats might show mild upper respiratory
signs (sneezing) or diarrhea, but are so mild that they can go unnoticed. When serious symptoms do appear, the signs might
be sudden in the younger cats, or more gradual in older cats.
Cats that have dry form have vague symptoms that come and go, and can affect many different systems
in the body. They might be lethargic, have poor appetites,weight loss and look ill. Common organs involved are the eyes, central
nervous system (brain and spinal cord), and internal organs like the liver and kidney. Other symptoms could include seizures,
paralysis, behavior changes, poor vision, increased sensitivity to touch, and urinary incontinence.
Another clue to dry FIP is a cat with an ongoing fever. It might wax and wane, and usually does not
respond to antibiotics.
Since many different organs can be involved with the dry form, the symptoms we see with this form of
FIP can mimic other common diseases of cats, like hyperthyroidism, liver disease, sugar diabetes and kidney disease. Other diseases like inflammatory bowel disease, cancer, and toxoplasmosis might also have similar symptoms.
Pets with the wet form of the disease may have breathing difficulty or distended abdomens, in addition
to some of the symptoms of the "dry form". The onset of these symptoms is faster than the gradual symptoms noted in the dry
form. The wet form of FIP is much easier to diagnose than the dry form.
The virus can also infect the brain or spinal cord. This form of the disease can sometimes be diagnosed
by an eye exam. Changes can be noted in the back of the eye, especially the retina.
Diagnosis is difficult in many cases, particularly in the dry form. We do not have a blood test that
tells us if the virus is present like we have with FeLV and FIV. The test we do have tells us if antibodies have been made to the category of virus that FIP belongs
to (coronavirus), but it does not tell us if it is the actual FIP virus or not. There are DNa type tests available that are
more specific in making this diagnosis, the most common one being the polymerase chain reaction (PCR) test. As we generate
more data on this test in sick cats its usefulness will probably increase.
In addition to specific FIP antibody or DNa tests, blood samples, X-rays and fluid analysis are also used, and are utilized especially in cats that have the wet form.
The only way to be 100% certain of the diagnosis is to biopsy one of the abdominal lymph nodes, the kidneys, or the liver.
Cats that have FIP will have physical exam findings similar to other feline diseases. In the wet form
the fluild buildup in the abdomen becomes apparent as time goes on.
The white blood cells might be low, normal or high, depending on how long the problem has been present
and if other problems also exist. The red blood cell count might be normal or low (anemia).
The biochemistry profile commonly reveals an elevation in total protein and globulins. This elevation
comes from the inflammatory process occurring as the body responds to the virus. This increase, called hyperglobulinemia,
occurs more often in the dry form.
There is no treatment that will cure this disease. Over the years many different treatments have been
attempted to alleviate symptoms of this disease. Some of them seem to work for variable periods of time, so they are worth
trying in some cases. These include antibiotics, antinflammatories, immune system stimulators, and vitamins. Since it is difficult
to confirm the presence of this disease, especially in the dry form, it is worth the effort to treat your cat symptomatically.
Unfortunately, the long term outcome is poor. Cats with confirmed cases of FIP usually succumb within a few months.
Antiviral medications have been tried but do not appear to alter the course of the disease.
You can find these treatments in our section on FeLV, since both diseases are treating the symptoms of the virus and not the actual
virus. The caveats in treating FeLV also apply to FIP.
Cats living in households that already had a cat die of FIP have a less than 5 percent chance of developing
FIP, mostly because they have already been exposed to the virus and fought it off. Siblings of cats that died of FIP have
a greater chance of developing the problem. The most important factor in controlling FIP is limiting the number of cats in
a house, preferably to less than 5. In addition, good nutrition, good veterinary care, and good sanitation, will go along
way to preventing this problem.
Wait at least one month before introducing a new cat to house that
had a cat die of FIP. Cleaning the litter pan often and preventing litter from tracking throughout the house may be helpful.
The virus can live in the environment for several weeks, so clean as thoroughly as possible using a 1:32 dilution of household
bleach. Remove all cat related products that can not be thoroughly cleaned.