Peritonitis in Cats

FCoV is contagious; cats contract the infection through direct and indirect contact with infected cats. Sharing a litter box or otherwise coming into contact with infected feces is the most common way the disease is transmitted.

Feline infectious peritonitis, or FIP, is an incurable and usually fatal condition in cats caused by infection with a mutated strain of the feline coronavirus (FCoV). FCoV by itself may not be fatal; in fact, nearly forty percent of cats will be infected with FCoV at some point and continue to live healthy lives. When FCoV mutates, however, it will cause FIP. Mutation, although rare, is more likely to occur in households with multiple cats.

Most cats will not show any symptoms during the initial stages of infection. By the time symptoms begin to appear, the disease has progressed and the prognosis is poor. While none of these are specific to FIP, seek immediate veterinary attention as soon as you notice the following symptoms:

• Swollen abdomen or chest
• Difficulty breathing
• Loss of appetite
• Lethargy
• Fever
• Weight loss
• Vision problems
• Jaundice
• Seizures

Types

There are two types of peritonitis in cats: effusive and non-effusive peritonitis. Effusive, or “wet”, FIP is characterized by difficulty breathing and a buildup of fluid in the abdomen, which causes it to swell. Cats infected with non-effusive, or “dry”, FIP have a lesser buildup of fluid, but may experience jaundice or vision problems.

The causes of FIP in cats are not fully understood. There are two serotypes, or microorganism strains, of FCoV. The prevalence of each serotype is based on geographic region. Serotype I is most often diagnosed in cats living in the United States. However, both serotypes can trigger the development of FIP. Veterinary researchers have speculated that, when the feline immune system fails to eliminate infected macrophages, FoCV will spur a fatal, immune-mediated reaction: FIP. Even so, it is unclear where the mutations originate.

A strong response from the cat’s immune system during the initial stages of infection may fight off virulent strains of FCoV that produce FIP. While any cat can develop either virus, young kittens and those that live in multi-cat households or crowded environments (such as shelters) have a higher predisposition for contracting the disease. Purebred cats, as well as sexually intact males, also have an increased risk for developing FIP.

When you arrive at the vet clinic or hospital, be sure to let your vet know the extent and duration of your cat’s symptoms, if your cat has recently had contact with other cats, or if you live in a multi-cat household.

Diagnosing FIP is often difficult; no tests for FIP currently exist. Blood and fluid tests may assist in making a diagnosis, but neither is accurate enough for a definitive diagnosis. The vet may conduct the following tests: immunostaining FCoV, DNA analysis, antibody measurements, and ultrasounds. Some tests are unsuitable for certain cats, and the vet will determine which test to conduct on an individual basis. However, many tests often return a false negative result, even if the cat is infected with FIP. Unfortunately, in many cases, the disease is only identified after the cat has perished.

Sadly, there is no cure for FIP, and it is often fatal within two weeks of diagnosis. Some infected cats diagnosed during the early stages of the disease have a better prognosis.

Treatment, therefore, is mostly palliative, or done to relieve the cat’s suffering rather than curing the underlying disease. Immunosuppressants and modulators are often prescribed to suppress the overactive immune system. The vet may choose to remove the fluid build-up to help relieve symptoms.

Intravenous fluid and nutritional therapy are often utilized in cats with FIP. The vet will monitor the cat’s condition and quality of life carefully. If infected cats don’t seem to be improving within three days of treatment, euthanasia is typically recommended.

Recovery may not be possible for cats infected with FIP. However, be sure to follow your vet’s post-treatment and recovery instructions carefully to ensure the best quality of life for your cat.

If you live in a multi-cat household, you’ll need to ensure your other cats have not been infected with FCoV or FIP. Isolate any infected cats. Always keep litter boxes clean and free of feces, and ensure that your cats are not overcrowded. Make sure your cats’ vaccinations are up-to-date and that they are receiving proper nutritional care. Minimizing stress may also help in preventing FCoV or FIP, as excessive stress weakens the immune system.

There is one vaccine available for FIP, although it has proven ineffective in most cases for preventing the disease. There is no way of discerning whether or not a cat infected with FCoV will develop FIP.