Feline Infectious Peritonitis - FIP

FIP is a cat virus that can be fatal. A cat that has FIP can have a variety of vague signs, including fever, lethargy, weight loss, or just not acting right. Some cats with FIP will have difficulty breathing or a swollen belly. Once signs start, there is no effective treatment. There is a blood test for FIP, but it is not a very good test. A negative test result can mean no exposure. A positive test result means exposure, but not all cats that are exposed will develop the fatal signs. The only true diagnosis is by biopsy or post-mortem diagnosis. Thirty percent of cats test positive for the virus, but 99% of them never develop signs of FIP. It is theorized that the disease occurs because the virus mutates or changes; stress is also a factor. The disease is believed to be passed cat-to-cat by contact with saliva, urine, or stool. The virus can live in the environment for several weeks, but can be easily killed with disinfectants such as bleach.

The disease seems to affect mainly kittens, especially aged 6 - 12 months. This may be due to an under-developed immune system. Two types of immunity work with this disease: Cell-mediated and Humoral. Cats with good cell-mediated immunity are able to fight off the disease, at least to some extent. They either do not get the disease at all or become carriers or get the "dry" form of the disease. There is no way to positively identify a cat that is a carrier of FIP. These carrier cats can infect other cats without showing any signs of FIP themselves. Cats with good humoral immunity mount a fantastic antibody response. The antibodies form complexes with the virus, and it is the immune complexes that cause the major problems of FIP. These cats get the "wet" form of FIP, with difficulty breathing or swollen abdomen or both. The only difference in clinical signs of the "wet" versus the "dry" forms of FIP is whether or not there is fluid in the chest or abdomen.

There is a vaccine for prevention of FIP. It is given in the form of nose drops. In the veterinary community, the vaccine is very controversial. The manufacturer states that the vaccine is 69% effective in their studies in protecting cats from getting FIP. Other groups have done studies to determine the vaccine is 50 - 75% effective in protection from FIP. Yet other groups have determined that the vaccine is not only ineffective, but if the cat has previously been exposed to FIP (positive antibody titer, carrier cat) then the vaccination may cause the cat to die from FIP. In our experience, over several years, we have not had any vaccinated cats get FIP. Vaccination before exposure is likely to be helpful in preventing FIP; however, vaccination of a cat that has already been exposed to FIP is not likely be helpful in preventing FIP.