Feline infectious peritonitis or FIP is a very dangerous disease for our pet cats. Luckily it is not a very common disease, occurring in only a very small percentage of cats. Most cats are infected at a young age often before a year and a half old. Once clinical signs start to appear however there is a greater than 95% chance of death. Here is what you need to know about this little understood feline disease.

FIP is caused by a strain of feline coronavirus. As we have learned recently with COVID 19, there are many different strains of coronavirus. Coronaviruses in general are very common and up to 90% of cats are infected with one strain or another. Most of these cats show no visible symptoms but can transmit the virus to other cats. The most common strain of feline coronavirus lives in the gastrointestinal tract where it can cause recurrent diarrhea. It is still unknown which strains exclusively cause FIP and often it is a mutation of this common strain that causes the disease. In most cats even if they do contract the deadly strain of this virus, their immune system is able to fight off any infection before it causes serious issues.

FIP shows up in two different forms. There is a wet form and a dry form. In the wet form, fluid tends to accumulate in the cat’s body in either the abdomen or more rarely the chest. You can see difficulty breathing if there is fluid in the chest or a swollen pot-bellied appearance if it is in the abdomen. The wet form is a little easier to diagnose as you can collect samples of the fluid to test in a laboratory. The dry form causes much more vague symptoms, but involves a lot of inflammation throughout the body. In either form, once clinical signs start to develop, the cat tends to become sick quite rapidly and the disease typically results in death within several weeks.

As mentioned above, you can collect fluid samples in the wet form of FIP to run laboratory analyses however even that is not definitive. Because so many strains of coronavirus exist and can cause FIP it is very difficult to test for. All of the tests currently available are unable to differentiate between the strains. Most of the time you do not get a diagnosis of FIP as much as have any other possibility ruled out. If your veterinarian does diagnose your cat as having FIP, unfortunately there is no treatment and the disease is almost always fatal so euthanasia is often the best option.

The viruses that cause FIP do not survive long in the environment. Basic household cleaning and hygiene practices will destroy it. Because of this, and the chances that most cats do not develop FIP despite being infected with the virus, means it is relatively safe to bring another cat into your household within a couple of weeks of having a cat with the disease. In multiple cat households, you should wait a couple months to make sure no other cats become ill before bringing any new cats home.

Overall, Feline Infectious Peritonitis is not a very common disease, but is a very deadly one. It is nearly impossible to accurately test for and there is no treatment or cure once clinical signs occur. As with any other illness it is important to bring your cat to the vet if you start noticing any signs that they are not feeling well.


Article written by: Heather