Feline Infectious Peritonitis (FIP) has long been a death sentence for infected felines, but within the past few years advancements have been made that can cure the disease. Read on to learn more about the disease and how the team at The Cats at Longstreet and Harmony Hill Animal Hospital are working to save those affected.
As recently as 3 years ago, all cat veterinarians and shelters lived in fear of feline infectious peritonitis, or FIP. At the time, this disease was 100% fatal and could strike at any time. Most often, it was seen in kittens who seemed healthy and then after adoption or getting spayed or neutered, they’d become progressively sicker, lose weight, and fluid would accumulate in their abdomen or chest. Happily, that has changed.
FIP is a syndrome. It’s not a simple cause and effect, but more of a recipe or a process. First, a cat must be exposed to a common, relatively benign virus called feline enteric coronavirus, or FeCoV. FeCoV only affects cats and in adult cats, it will often make them feel puny for a couple of days, they’ll have a decrease in appetite, and a few days of diarrhea.
In kittens, though, the diarrhea can be severe enough that they can die, and it’s probably one of
the leading causes of kitten death in shelters and rescues. It’s also highly contagious. Once it’s
introduced into a multi-cat environment, it is rapidly passed from cat-to-cat.
Like our human coronaviruses, FeCoV is always mutating. Once a cat has the benign enteric form inside their body, it can continue to mutate and, in some cases, the surface proteins on the virus will change in such a way that the virus gains the ability to hide from the immune system, but at the same time, it loses the ability to be transmitted directly from cat-to-cat. These mutated forms are called by many names, but we’ll call them the FIP-variant coronaviruses here.
Once a cat has the FIP-variant coronavirus, they have the first part of the recipe to potentially develop
FIP. We know that there appears to be a genetic predisposition. In catteries and breeding colonies, we’ll see FIP develop only in certain family lines, even though the whole facility is exposed to the same viruses and environmental factors. We think that all cats that develop FIP probably have an immune system that isn’t quite as healthy or robust as some others, and it makes them more likely to fall ill.
The final factor we usually see is what we call a trigger event. This event does not cause FIP all by itself. Rather, it provides just a tiny bit of additional physiological stress that further suppresses the immune system and provides a window for the virus to replicate in an uncontrolled fashion.
The most commonly recognized form used to be the wet form. We don’t think it’s because it’s truly more common, but easier to recognize.
Affected cats often have a high fever, don’t want to do anything, and either their bellies swell up like balloons, or they can’t breathe because their chests are full of fluid.
The wet form is easier to ‘prove’ because the fluid can be sampled and sent out for additional testing.
The other form we see is the dry form of FIP. This can be a lot harder to recognize because the clinical signs are highly variable. The disease we’ll see will depend entirely on where the immune system and the virus battle and form what are called granulomas.
The dry form can be harder to diagnose because you must either use a needle to extract samples of whatever might be abnormal or collect tissues at surgery for biopsy.
Once we find it, it can be treated. There’s a new treatment not yet approved in the United States that inhibits viral replication. It’s called GS-441524 (or GS, for short), and if pet owners can find it, we have at least an 80% cure rate when this medication is given at the appropriate dose for the appropriate time. Treatment is most often about 84 days, or 12 weeks, but it can be longer if a cat is very sick,
or the dose needs to be adjusted.
For cats affected with FIP and their families, this drug is nothing short of a miracle. All affected cats need to have their other symptoms treated, including nausea medications and appetite stimulants as needed, pain medications as needed, fluids if they’re dehydrated, antibiotics if they have other concurrent infections, and sometimes steroids to help reduce inflammation and make them more comfortable while the treatment is working. Cats who start on GS will usually show marked, obvious improvement within 2 or 3 days of starting the medication.
The Cats at Longstreet has been able to help treat dozens of FIP cats in the past 3 years, and we have found our place in helping to educate other rescues and pet owners. Treatment on average is around $2,000-3,000 for most cats. We’ve reached a time of radical change in feline medicine and are honored to be able to help spread the word that FIP is no longer a death sentence.