Feline FIP: Understanding A Deadly Cat Virus

What Is Feline Infectious Peritonitis

Feline infectious peritonitis (FIP) is a 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.

The following information isn’t intended to replace regular visits to your veterinarian.

If you think your cat may have feline infectious peritonitis, please see your veterinarian immediately. And remember, please do not give any medication to your pet without talking to your veterinarian first.

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, anorexia, 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.

Most cats initially are asymptomatic, but the virus is at work.

After ingestion, the virus immediately begins to replicate in the cat's pharynx and small intestine. From there it moves into the throat, lungs, stomach, and large intestines. About 1 to 10 days later, it can be spread to other cats.

During this time, cats may display the symptoms of a mild upper respiratory infection: sneezing, watery eyes, and nasal discharge. Others give the appearance of having intestinal problems: diarrhea, weight loss, and lethargy. Many cats have nonspecific symptoms: intermittent loss of appetite, depression, rough hair coat, weight loss, and fever. Most cats that undergo the primary infection recover fully, although some may become virus carriers.

A small percentage of exposed cats develop lethal FIP weeks, months, and even years after primary infection.

In some cats, especially kittens, the onset of symptoms may be sudden. In others, FIP symptoms may appear and increase in severity over a period of weeks. When the classic symptoms of full-blown FIP appear, the disease typically is diagnosed as wet (effusive) or dry (noneffusive), and many cats present symptoms of both.

When the FIP infection reaches the lymph nodes, it spreads throughout the cat's body. The disease is no longer contagious at this stage.

Signs and Symptoms of FIP - Wet Form

distention of abdomen due to fluid build up

difficulty breathing due to lung involvement

fever (long term, unresponsive to treatment)

loss of appetite

weight loss

depression

Signs and Symptoms of FIP - Dry Form

ever (long term, unresponsive to treatment)

loss of appetite

depression

weight loss

variable other signs related to organ failure, depending on which organs are involved (commonly involves kidneys, liver, pancreas, nervous system, eyes)

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 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 test usually (but not always) indicates that the cat is unlikely to have FIP.

There is no treatment or cure for FIP.

Some supportive measures, including draining excessive fluid build-ups can provide temporary relief. A variety of medications designed to reduce the abnormal immune response to the virus or reduce the ability of the virus to reproduce have been tried and may provide some relief from the disease.

Generally, cats with the wet form succumb to FIP sooner (days to weeks) than those with the dry form (few months), though survival for several months may be possible.

FIP 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. Fortunately, the disease is very uncommon. In households containing only one or two cats, the FIP mortality rate is around one in 5,000.

Preventing exposure to coronavirus is the best way to prevent FIP.

Keeping cats indoors offers protection, as well as only bringing coronavirus-negative cats into the household.

There is a vaccine available, although its use is controversial.

The vaccine is given in the nose, and is designed to produce just a local response to prevent the virus from gaining access to the body. The vaccine is not 100 percent effective, and must be given before natural exposure to coronavirus to be effective.

Because FIP is quite uncommon in the general cat population, the need for routine use of FIP vaccines is uncertain. Your vet can discuss the use of FIP vaccines in your cat.

The Multi Cat Household

Housemates of a cat diagnosed with FIP do not have a greater risk of developing FIP, unless they are litter mates that share a genetic predisposition. They have also likely been exposed to coronavirus already, so no special precautions are usually necessary. Your vet can provide further advice regarding home care.