FIP by the cat

FIP is a serious feline disease caused by a common diarrhea virus (coronavirus). This diarrhea virus is actually not that dangerous for the cat at all: after a day of diarrhea, most cats are not sick with it.
In some cats, the harmless gut form of the virus turns into a malignant variant that causes inflammation elsewhere in the body. We call this disease FIP (Feline Infectious Peritonitis, infectious peritoneal infection of the cat). This disease is serious.

Any cat can be unlucky enough to get FIP. Cats that live in a house with 6 or more other cats have an increased chance of developing FIP. 90% of cats with FIP are less than a year old. The other 10% is often older than 10 years.

The corona virus

The Feline Coronavirus (FCoV) is a highly contagious but harmless virus that causes intestinal infections. The coronavirus causes mild diarrhea complaints. But more often infected animals do not show any symptoms. Many cats encounter the virus once in their life. Most of the animals that come into contact with the normal virus overcome the virus before it can become malignant.


FIP stands for Feline Infectious Peritonitis. That means contagious peritoneal infection of the cat.

With the wet form of FIP, there is a lot of moisture in the cat’s abdominal cavity. The pleura may also be inflamed: there is then fluid in the chest.

The dry form of FIP affects organs such as the liver, kidneys, intestines, brain or spinal cord. Some animals have a mixture: wet and dry.

FIP symptoms

Cats with FIP often have a fever and show weight loss.

Wet form

  • Bulky abdomen: fluid in the abdominal cavity.
  • Shortness of breath: fluid in the chest cavity.

Dry form

  • The phenomena depend on the organs that are affected.
  • Cloudy eyes, blood, or pus in the eyes from eye inflammation.
  • Abnormal behavior in inflammation of the brain.
  • Shortness of breath when attacking the lungs.
  • Jaundice when affecting the liver.
  • Pale anemia.
  • Kidney failure when affecting the kidneys.

 FIP diagnosis

Belly or breast fluid is clear, yellow, or light orange. Often the moisture is sticky and slimy (thread-drawing).

Evidence-based diagnostics

  • The FIP virus can be detected by a so-called “immunofluorescence test on macrophages” (in breast / abdominal fluid, in the wet form) or “immunohistochemistry” in tissue samples (in the dry form). Since 2014 there has also been a PCR test to demonstrate the mutation in the virus.
  • If these tests are negative, FIP is still not excluded.

Supporting diagnostics

  • Some cats are anemic.
  • An increased protein level in the blood (gamma globulins).
  • A high protein content (> 35 g / l) in the abdominal fluid or in the fluid from the chest cavity (albumin / globulin ratio <0.8).
  • The moisture contains hardly any cells.

Non-meaningful diagnostics

  • A positive FIP titer (blood test) does not show FIP. It indicates that an animal has recently been exposed to the coronavirus, but does not show whether we are dealing with the benign or malignant variant.
  • A negative FIP titer does not exclude FIP.
  • A PCR test of the stool (PCR stands for polymerase chain reaction, it is a test that shows the RNA of the virus) can detect the corona virus in the stool, but it is probably the benign variant.

Treatment FIP

Treatment of FIP is usually unsuccessful, and the disease is almost always fatal. Supportive therapy can, however, improve the quality of life and extend the lifespan.

This assisted therapy may include aspirating the inflammatory fluid from the chest or abdominal cavity, providing tube feeding, infusions and antibiotics for secondary infections.

Some cats have been helped with medicines that affect or suppress the immune system (prednisone, prednisolone or dexamethasone).

Although various treatments for FIP can be found on the Internet and in books, there is little scientific evidence that these treatments actually work. Virus inhibitors and interferon do not seem to work.

There is no known treatment that inhibits the development of FIP in FCoV infected cats.

Life expectancy FIP

FIP is a deadly condition. How long the cat has to live depends on the clinical condition when making the diagnosis. Some cats live several weeks to months.
Animals are often euthanized after diagnosis.

FIP is not contagious, but the corona virus is

The change from the harmless coronavirus to the deadly FIP virus takes place in the patient himself. The FIP virus is rarely secreted. So there is no direct transmission of the malicious virus. But the more cats infected with the harmless gut virus (which is easily transmitted), the more likely one cat will develop FIP.

Prevention of infection with the coronavirus

Combating the benign variant of the virus reduces the chance of getting FIP.

The coronavirus spreads through the feces. By keeping your house as clean as possible and then disinfecting it, you can reduce the chance of contamination. Cats with FIP can also excrete the coronavirus. For this reason, we recommend that you do not take a new cat into your home for the first 2 months after the death of a cat with FIP. And if you have multiple cats, you can have your cats and the new cat examined on FCoV before putting them together.

There is a vaccination against FIP, but the efficacy has not been proven. Vaccination is generally not recommended and does not protect against mutation of the FCoV in an already infected cat. Vaccination probably only makes sense when fighting FIP in a cattery.
There is a control program for the cattery. In this control program, kittens can be vaccinated, which are removed at 5 to 6 weeks of age from female cats that have been tested positive for the disease.


The Coronavirus, which causes diarrhea, is itself a fairly harmless virus. However, we must treat it with care and hygiene.

The malicious variant, FIP, is usually fatal.