Pet Care

Feline Infectious Peritonitis

Striped cat napping on a towel

What is feline infectious peritonitis?

Feline infectious peritonitis (FIP) is a devastating viral disease that occurs worldwide in wild and domestic cats. It is caused by a type of virus called a coronavirus, which tends to attack the cells of the intestinal wall. In 1970, the coronavirus that causes FIP was isolated and characterized. In 1981, another coronavirus was isolated. Although this virus is nearly identical to the FIP virus, cats who were infected with it developed only very mild diarrhea and recovered easily.

What are the symptoms of FIP?

FIP manifests in a “wet” form and a “dry” form. Signs of both forms include fever that doesn’t respond to antibiotics, poor appetite, weight loss and lethargy. In addition, the wet form of FIP is characterized by accumulation of fluid in the abdominal cavity, the chest cavity, or both. Cats with fluid in the chest exhibit labored breathing. Cats with fluid in the abdomen show progressive, nonpainful abdominal distension. In the dry form of FIP, small accumulations of inflammatory cells, or granulomas, form in various organs, and clinical signs depend on which organ is affected. If the kidneys are affected, excessive thirst and urination, vomiting and weight loss are seen; if the liver, jaundice. The eyes and the neurologic system are frequently affected, as well.

How is FIP diagnosed?

Diagnosing FIP is challenging. Despite the claims made by some laboratories and test manufacturers, there is currently no test that can distinguish between the harmless intestinal coronavirus and the deadly FIP coronavirus. A positive coronavirus antibody test may support the veterinarian’s suspicions, but by itself is inconclusive. It means only that a cat has been exposed to and may be harboring a coronavirus. A negative antibody test usually (but not always) indicates that the cat is unlikely to have FIP.

There are other tests that can help support a diagnosis of FIP, such as ultrasound or body fluid analysis, but no test is definitive. Which tests may be recommended for a particular cat depends on that individual animal’s situation. 

How is FIP treated?

There is no effective treatment for FIP, which is fatal in more than 95 percent of cases. In mild cases of the dry form, it may be possible to prolong the survival period, but most cats with the wet form of the disease die within two months of the onset of signs. 

Is there a vaccine for FIP?

An intranasal vaccine was developed to prevent FIP in cats, but it has been controversial. According to the 2006 vaccine guidelines published by the American Association of Feline Practitioners, the vaccine is not recommended, and the guidelines state: “According to the limited studies available, only cats known to be feline coronavirus antibody negative at the time of vaccination are likely to develop some level of protection. Vaccination of cats living within households in which FIP is known to exist or cats that are known to be feline coronavirus antibody positive is not recommended.” 

This information was adapted from an article written by Arnold Plotnick, DVM.