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Feline Infectious Peritonitis (FIP)

What is feline infectious peritonitis (FIP)?

Feline infectious peritonitis (FIP) is a systemic viral disease that damages various body tissues. Two forms of the disease are recognized: the wet form and the dry form. In the wet form, inflammatory fluid accumulates in the chest or abdomen. In the dry form, the virus attacks various organs, such as the kidneys and spleen. There is no cure for FIP and the disease is almost invariably fatal. Feline infectious peritonitis is diagnosed most commonly in kittens and adult cats less than three years of age. Cats in breeding catteries or in multi-cat households are at an increased risk of developing this disease.

What causes feline infectious peritonitis (FIP)?

Feline infectious peritonitis (FIP) is caused by a coronavirus. The virus can be transmitted by close cat contact or through environmental contamination of litter boxes and food dishes. In some cases, the virus can be transmitted to kittens from their mother's milk. Cats that are positive for the feline leukemia virus (FeLV) may be more susceptible to developing FIP.

What are the signs of feline infectious peritonitis (FIP)?

Some common clinical signs seen in FIP include gradual weight loss, stunted growth, decreased appetite, pot-bellied appearance, persistent fever, depression, poor hair coat, and jaundice (yellowing of the gums, inner ear, and eye). Cats with the wet form of FIP also may have difficulty breathing due to fluid accumulation in the chest.

How is feline infectious peritonitis (FIP) diagnosed?

Feline infectious peritonitis (FIP) is diagnosed with a good history and physical examination. The clinical signs vary between affected cats. The wet form of FIP is relatively easy to diagnose based on the presence of the typical fluid in the chest or abdomen. Blood and urine testing may provide additional diagnostic information. Radiographs (X-rays) may be taken to confirm the presence of fluid in the body cavities. A sample of fluid, obtained from the chest or abdomen, will have a characteristic pale to straw-colored appearance with white flecks of fibrin in it. The dry form of FIP is more difficult to diagnose depending on the type of organs and tissues involved. In some cases, an exploratory surgery may be required in order to confirm the diagnosis of FIP. Unfortunately, a single test that can be used to diagnose FIP reliably does not exist.


A New Test to Help Diagnose Feline Infectious Peritonitis (FIP)
Fiona Hickford, BSc, MVSc

Feline infectious peritonitis (FIP) is a viral disease of cats that can cause depression, fever, loss of appetite, weight loss, fluid in the abdomen or chest (called wet form), organ dysfunction, neurological problems, masses, ocular problems, and death. Currently the definitive diagnosis of FIP requires tissue biopsy for special testing (immunohistologic techniques). However, collecting biopsies may not be possible in severely ill cats suspected of having FIP. Other tests only aid the veterinarian in making a diagnosis, but they do not lead to the definitive diagnosis of FIP.

A study was designed to compare current diagnostic testing methods used for FIP with a new test called the "direct immunofluorescence test" (DIF). This test is performed on fluid from the abdomen or chest cavity of ill cats suspected of having the wet form of FIP.

It was determined that the DIF test performed on abdominal or chest fluid from an ill cat appears highly sensitive and specific. A positive test appears to confirm the diagnosis of FIP. The DIF test is the first noninvasive specific test for FIP. However, a negative test result does not exclude the possibility of FIP. At this time, the only true definitive test for FIP is to detect the virus in tissue biopsy samples (immunohistochemistry).

How is feline infectious peritonitis (FIP) treated?

There is no effective treatment for FIP. Although immunosuppressive drugs have been used, their success is limited. All cats with FIP should be isolated from other cats to prevent the spread of this disease. Supportive therapy may be provided to make the cat more comfortable. For example, a cat with the wet form of FIP may find it easier to breathe if the fluid is drained from its chest cavity. Routine cleaning of the environment, cages, and food and water dishes with disinfectants is required to inactivate the virus and reduce the spread of FIP between cats. A vaccine is available, but it may not fully protect a cat against this disease.

What is the prognosis for cats with feline infectious peritonitis (FIP)?

The prognosis (outcome) for cats with FIP is grave. Feline infectious peritonitis (FIP) may cause clinical illness in a cat for a few days to several months. However, once the typical clinical signs for FIP have appeared, nearly 100% of affected cats will die

Coronavirus Infection in Cats
(feline infectious peritonitis (FIP), coronavirus enteritis)

General Information

Feline coronaviruses include those that cause feline infectious peritonitis (FIP), and those that cause only a mild intestinal disease (coronavirus enteritis). The viruses are not the same, but they cannot be differentiated by the current blood test. A positive blood test will alert the doctor to the possibility of these diseases, and a negative test will help rule them out. Blood tests have value in the overall diagnosis and evaluation of your pet's illness.

Feline infectious peritonitis is relatively uncommon and generally fatal. It occurs primarily in cats between 6 months and 5 years of age. Two forms of FIP occur: (1) a disease of the lining of the abdominal and/or chest cavities, in which massive fluid accumulations occur ("wet" FIP), and (2) a disease of various organs, such as the lymph nodes, kidneys, eyes and brain ("dry" FIP).

Feline enteric coronaviruses cause mild intestinal disease in kittens up to 12 weeks. The infection is common and probably exists in most homes with more than one cat. It may recur throughout the cat's life but is rarely serious.


1. There is a vaccine available to prevent the occurance of FIP in cats. It is not part of the regular routine vaccines recommended at Foothills Animal Hospital. If you have an outbreak of the disease in your community or household vaccination should be done. The use of this vaccine should be dicussed with your veterinarian.

2. Premises where FIP-affected cats have been kept should be treated with a disinfectant and left cat-free for some time. Your veterinarian will make specific recommendations.

The majority of the information in this page is has been taken from VetMedCenter.com. For further information about this useful source of informtion follow the link or look, on the internet, at www.vetmedcenter.com.