Feline Infectious Peritonitis
Oh, it starts out innocently enough. It’s caused by certain strains of the feline coronavirus, most of which don’t even cause disease or, if they do, may cause fairly mild intestinal or respiratory symptoms.
But sometimes, at some point, either the virus mutates or the cat’s immune system malfunctions and the disease develops into FIP.
In a cruel twist of fate, the disease turns the cat’s own defenses against it. White blood cells, which normally protect against invaders that can do harm, become infected with the virus and carry it throughout the body.
These cells collect in the abdomen, and sometimes in the kidney or brain, and ignite a severe inflammatory reaction in the tissues of those involved areas. Once symptoms develop, the disease gets worse and worse over ensuing weeks until the cat finally succumbs.
Animals, including pets that you think would know better, will instinctively hide symptoms of illness or injury because, in their world, if you’re vulnerable, you’ll get beaten up or eaten. Domestication hasn’t particularly changed that.
And cats seem to be particularly adept at it until the situation they’re hiding reaches the crisis stage. Therefore, even though the disease has been simmering for a long time, it may seem to you to have developed almost overnight.
There are two forms of FIP; the dry form and wet form. Cats exhibiting symptoms of the dry form may become lethargic, lose weight, and have a persistent fever. These symptoms are more gradual than those of the wet form.
Symptoms of the wet form progress more quickly as the cat becomes pot-bellied due to an accumulation of fluid in the abdomen or, less commonly, in the chest. If the build up of fluid becomes excessive, the cat may find it hard to breathe normally.
Since there is no test to confirm the disease at the onset of symptoms, veterinarians presume the diagnosis based on the symptoms that bring the cat to the clinic, the cat’s medical history, and a battery of lab tests.
The disease is more common in multi-cat environments, but in the general cat population is seen more often in kittens, older cats, cats infected with feline leukemia (FeLV), or cats with compromised immune systems.
FIP can’t be cured yet, so all one can do is support the cat with proper nutrition and good medical care. Veterinarians can drain accumulated fluid, and provide fluid therapy, blood transfusions, and drugs to hopefully induce a period of remission.
Otherwise, about all you can do to possibly protect your cat is maintain optimal health, provide a high quality diet, be vigilant about litter box and other sanitation issues, determine with your vet what vaccinations should be updated, and get advice from your vet about a quarantine period for any new cats brought into your home.
There is a vaccine available, but it’s known to have minimal, if any, preventive qualities. You might decide it’s worth a shot, but you should have a “risks vs. benefits” discussion with your vet about it first.