Feline Infectious Peritonitis

This virus is highly aggressive and affects many systems in the body, including the gastrointestinal tract, the lungs, and the neurological system. It is more common in cats less than 3 years of age. The diagnosis of FIP is difficult and in most cases, it is a diagnosis of assumption.

FIP is caused by viral transmission from cat to cat, usually through saliva. Many cats carry antibodies to the virus, but only very few show clinical signs of the disease.

There are two forms of FIP: wet and dry. The wet form will cause fluid to accumulate in either the abdomen or around the lungs. The dry form will affect many organs just like the wet form, but will not have the fluid accumulation. Most cats have a persistent fever that is unresponsive to antibiotics. They will also have vague signs in the dry form: decreased appetite, weight loss, depression, dry hair coat. In the wet form, their abdomen will become bloated or they will begin to have respiratory difficulty.

The hardest part about this virus is obtaining a definitive diagnosis. The current test available can only detect exposure to the virus and does not differentiate cats that do not have the actual disease. In other words, totally healthy cats can have positive FIP tests and not be sick and patients with FIP can be negative. If the patient has the wet form and a positive test, it can be assumed at that point that the patient is probably harboring the virus.Treatment is strictly palliative. Unfortunately, this disease is 100% fatal. The current vaccine available is not greatly protective and usually is not recommended.  The best prevention is to keep your pet inside and test any new cats before introducing them into the household.