Cats with FIP are infectious to other cats during the initial two to four week period immediately following infection. It is at this time that large numbers of viruses are shed. After this stage, the virus becomes inactive within the cat and the cat does not show any signs of disease. This stage may last for several months or even years. If during this time the cat becomes stressed in any way, virus shedding may occur and any cat exposed may get the disease. Eventually, however, the patient becomes clinically ill. This final stage lasts only a few weeks and usually ends in death. Recovery is extremely rare.
Diagnosing FIP can be both difficult and frustrating since there are no specific tests that are completely reliable. Diagnosis is often based on a combination of blood tests, fluid analysis, x-rays and biopsies. There is no effective treatment available and euthanasia is usually recommended.
Even though a vaccine against FIP is available, most veterinarians do not recommend routine vaccination against FIP. Vaccination is, however, recommended for cats that routinely go outdoors and come in contact with other free-roaming cats. It is also recommended for cats that come from households that have had a cat with FIP.