FIP stands for feline infectious peritonitis. This disease occurs when feline coronavirus, or FCoV, mutates inside a cat’s body. The mutation results in the FIP virus. 

FCoV itself is already present in many cats, and if signs of illness ever present themselves, it usually shows up as mild diarrhea. In fact, over half of all domestic cats have FCoV, but those who develop FIP only amount to less than 10% of cats. So, it’s safe to assume that your cat, especially if you adopted from a rescue or shelter, has already been exposed to FCoV. This does not immediately indicate that your cat will develop FIP.

The most heartbreaking fact about FIP is that when it’s left untreated, FIP is fatal. Research is still being done on what directly causes FIP, but the information below can help you monitor for signs and communicate effectively with your veterinarian. 

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For Dante

This post covers the signs of FIP, your options, and support for you and your beloved feline companion. If you’re comfortable reading beyond that, you’ll find the story of a precious cat named Dante. His family inspired me to write this post. As they searched and searched for comforting resources during the thick of Dante’s struggles, they found nothing productive, nor anything written without medical jargon.

My hope is that this post informs fellow cat owners of how to monitor their cats for symptoms of FIP, or that it comforts someone in a time of need.

If you’re here because your cat or kitten has been diagnosed with FIP, I extend the biggest virtual hug to you and your companion. Please know that you are not alone. This post is intended to be read with the pace of your slow, deep breaths, and I sincerely hope it offers you some degree of comfort. Pause, talk with your vet, and think about all the options you have. 

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Here’s the entire list of resources in this post. PLEASE click through them and do your research. 

• Diagnosis of Feline Infectious Peritonitis
• Feline Infectious Peritonitis: Still an Enigma?
• FIPTreatment.com
• Efficacy and Safety of the Nucleoside Analog GS-441524 for Treatment of Cats with Naturally Occurring Feline Infectious Peritonitis
• FIP Warriors
• SOCK FIP
• Rainbows Bridge

What is FIP?

FIP stands for feline infectious peritonitis. This disease occurs when feline coronavirus, or FCoV, mutates inside a cat’s body. The mutation results in the FIP virus. 

FCoV itself is already present in many cats, and if signs of illness ever present themselves, it usually shows up as mild diarrhea. In fact, over half of all domestic cats have FCoV, but those who develop FIP only amount to less than 10% of cats (Tasker, 2018). So, it’s safe to assume that your cat, especially if you adopted from a rescue or shelter, has already been exposed to FCoV. This does not immediately indicate that your cat will develop FIP.

The most heartbreaking fact about FIP is that when it’s left untreated, FIP is fatal. Research is still being done on what directly causes FIP, but the information below can help you monitor for signs and communicate effectively with your veterinarian. 

How do Cats get FIP?

Cats and kittens can develop FIP if they’ve been infected with FCoV, but only if FCoV mutates in the cat’s body. FCoV can be passed from cat to cat through the fecal-oral pathway. This means that when cats shed FCoV in their stool, other cats can come into contact with the virus via the litter box. However, there is scientific evidence that only FCoV, not FIP itself, is passed from cat to cat (Kipar & Meli, 2014). 

Veterinary research also holds that the genetics and environment of each individual cat impacts whether or not FIP will develop. For instance, a cat’s immune system response and stress levels can increase the likelihood that FCoV will mutate, causing the development of FIP. It’s also been found that recent stressful events, such as surgery, vaccinations, illness, and living in an animal shelter can promote the mutation of FCoV into FIP (Tasker, 2018).

What are the Signs of FIP?

FIP typically presents itself in either an effusive (wet) form, a non-effusive (dry) form, or a combination of the two (Kipar & Meli, 2014). It is most common for FIP to occur when a cat is younger than 2 years or older than 10 years. The likelihood is far greater for those under 2 years than those older than 10 years, so please observe your cat carefully when they’re young (Tasker, 2018).

The effusive form, or wet form, is the most common form of FIP. It typically presents with:

• A swollen or distended abdomen
• A buildup of fluid in the area between the lungs and the chest
• Fluid around the heart
• Scrotal swelling in male cats

The non-effusive form, or dry form, of FIP typically presents with:

• A variety of neurological symptoms such as seizures, changes in behavior, and a lack of muscle control.
  • The lack of muscle control can be referred to as ataxia, which presents similarly to feline cerebellar hypoplasia.
• Loss of vision or cloudiness of the eyes
• Bumps or growths in the cat’s skin

It is also possible that a cat can have both forms of FIP at once. General signs to look out for include:

• Lethargy
• Fever
• Anorexia, weight loss, or lack of growth
• Diarrhea
• Lessened or loss of appetite 

(Tasker, 2018)

Unfortunately, some of these signs overlap with other common feline illnesses. This is why it’s so important to monitor your cat during all life stages, to take them to routine vet appointments, and to contact a trusted vet immediately when something is not right. 

How do Cats get Diagnosed with FIP?

From what I’ve read, cats are most commonly diagnosed with FIP after they have passed away. This is because some veterinarians and cat owners decide that the required invasive tests, such as biopsies, may cause more unnecessary stress for a cat who is already ill and uncomfortable. 

Your veterinarian may also explore your cat’s health history to decide whether or not more testing should be done (Tasker, 2018). However, I’ll list some different diagnostic pathways below that you can discuss with your veterinarian. A diagnosis of FIP, if accessible to you, will be especially important while you make any treatment decisions.

A trusted veterinarian

Having a veterinarian you trust that knows your cat and their health history is of the utmost importance. Ask your vet what they know about FIP and what signs they will look for as your cat ages. 

A veterinarian who is knowledgeable of FIP and knows your cat’s history will be able to test for other health conditions to rule them out. If your cat has the classic signs of FIP and the other tests come back negative, your veterinarian may diagnose your cat with FIP. 

There are more clinical ways to diagnose a cat with FIP, but again, having a veterinarian you trust is the most important tool you have. 

FCoV antibody tests

These tests use your cat’s blood sample to test for the presence of FCoV. A positive result means that your cat has been exposed to FCoV, but it does not indicate the presence of FIP nor does it indicate whether or not your cat will develop FIP (Tasker, 2018).

If you and your veterinarian decide to test your cat for FCoV antibodies, it’s important to know that some cats with FIP have received results with higher FCoV antibody counts than healthy cats. However, in rare instances, some cats who are already diagnosed with FIP can receive negative FCoV test results (Tasker, 2018). 

What all this means is that it’s probably best if you don’t rely on a FCoV antibody test alone to determine whether or not your cat has FIP. This diagnostic route may be more helpful when paired with another tool. 

Tissues samples and fluid samples

Tissue samples seem to be the most reliable form of FIP testing, along with the analysis of fluid buildup. Your veterinarian can use an ultrasound to find out if and where your cat has a fluid buildup and how much fluid there might be (Tasker, 2018). If necessary, your veterinarian may recommend drawing some of the fluid from your cat to run some tests on it.

The tissue sample option obviously involves an invasive procedure for your cat. If your cat is not too ill, your veterinarian can take a tissue sample from lymph nodes, the liver, or kidneys to analyze them (Tasker, 2018). Please know that if you don’t feel comfortable putting your cat through this procedure or cannot afford to do so, it’s okay. 

If the tissue samples or fluid samples come back positive for FIP, you and your vet can work together to make an informed decision about next steps. It’s unfortunate that an FIP diagnosis requires such invasive procedures. However, this again highlights how important it is to have a strong relationship with a veterinarian who is knowledgeable of FIP and of the most current research.

What are Your Options if Your Cat has FIP?

I often hear people say, “Oh, what we wouldn’t do for our pets.” In a perfect world, we would all do everything in our power to give our pets happy and healthy lives. Still, we have to acknowledge that not everyone can do so. It’s not always realistic. Whether it’s based on your morals or financial situation, you have to do what’s right for you and your beloved fur baby. You are no less of a person or a pet parent if you cannot commit to these options at this time.

Not every option will feel right to you. Maybe none of them will. My hope is that you’ll trust yourself to make a decision that feels right, doable, and realistic to your unique situation. 

Palliative care

Palliative care involves the basic treatment of FIP symptoms as they arise. As long as your cat is not at the point of suffering, owners can explore this option. 

Examples of palliative care include:

• Ensuring your cat eats at least 200 calories per day
• Giving them at least 60 milliliters of water each day
• Addressing anemia with vitamin B12 injections or supplements
  • Signs of anemia include pale or gray-looking gums and ingesting non-food items
• Addressing diarrhea with probiotics mixed in your cat’s food once a day

PLEASE visit FIPTreatment.com for much more detailed information and a comprehensive palliative care guide, from how to encourage your cat to eat enough to what to do if your cat has a fever.

Medical treatment

There is a relatively new drug called GS-441524, or GS, that has the potential to cure cats and kittens of FIP. Unfortunately, as of 2022 it’s still not easy to access, but it can be done. Here’s a summary of the safety of the drug and how effective it can be. 

GS is an antiviral medication that stops the FIP virus from replicating within the cat. The most common minimum treatment course is 84 days via injections, but there is also a pill form available (Pedersen et al., 2019).

In one study conducted on the safety and efficacy of GS, 25 out of 31 cats were considered FIP survivors at the time of the article’s publication. This means that the 25 cats were tested, no longer had FIP, and had not gone into a symptom relapse. Some of the survivors had to receive more than one round of treatment before the end of the study, and some of the 6 cats who did not survive had other underlying health conditions (Pedersen et al., 2019). 

For those with successful treatment outcomes, the cats experienced:

• Normal temperatures/no fever
• Return of their appetites
• Weight gain
• Increased activity and play
• Loss of fluid buildup (effusions)
• Return of eye health and normal function

(Pedersen et al., 2019)

The most common side effect of GS in this study was skin reactions where the injections were given. However, no other negative effects were found. Liver and kidney function remained normal, and young kittens did not have any growth defects. Please also know that the GS drug has been tested both in experimental (artificially induced) FIP and naturally-occuring FIP. I plan to discuss experimental treatment in a later post, but this study in particular only included cats with naturally-occuring FIP (Pedersen et al. 2019).

From what I’ve read in this article and heard from personal experiences, GS can be very effective to treat and cure FIP in cats. Please know that for financial reasons, among many other factors, this is not always the most realistic option for pet parents. However, it’s amazing that there is finally an option for those who are able to make this commitment.

Humane euthanasia

You know your cat and your unique situation better than anyone else does. If the medication and/or palliative care routes are not right for you and your feline friend, then that’s okay. It’s your reality. The downsides to long-term care are real and need to be acknowledged. Financial loss, time commitment, and the wellbeing of your cat are just some of the things to consider.

Watching an animal you love go through something as awful as FIP can be frustrating and gut-wrenching. If you have arrived at the point of making the difficult decision to help your cat cross the rainbow bridge, you are not alone. 

If euthanasia is your best option, please ask your vet what to expect. In my personal experience, each vet handles the process differently. In general, the vet will administer an injectable sedative that helps your cat fall into a peaceful sleep. Once your friend is resting comfortably, the vet will inject the substance that will peacefully guide them over the rainbow bridge. 

Things to consider

While you’re discussing euthanasia with your vet, please do not be afraid to ask for what you want or to say no to something.

If you have the time, make the day or moments before all about your special kitty. Spend quality time with them, give them their favorite snacks, and let them soak up some sunshine. When the time comes, you should be able to stay present with your cat and hold them close if you wish. Consider bringing something special with them, such as their favorite blanket, toy, or bed. 

Give yourself time to grieve. Despite what some might say, the loss of a pet can truly feel like the loss of a family member. 

Breathe. Your cat is resting in peace, and you’ve done everything you could do. You may choose to honor your cat in different ways by having them cremated or buried. You can also make or ask for different keepsakes, such as paw prints and impressions. 

Some pet parents have opted to donate the cat’s body to FIP research. The donation can contribute to the research of the efficacy of GS and contribute to FIP research in general. If financial factors are on your mind, but you would like to consider this option, please know that there are some researchers out there who are interested in conducting post-mortem research at a lower cost or even entirely for free. 

Support

There are several amazing support groups out there for whatever the outcome is. I’ll list them below and note what each group focuses on. If you’re here because you’re simply taking time to learn about FIP, please consider supporting these groups by donating to their cause and raising awareness.

FIP Warriors provides cat owners with an option to access the GS medication. You can visit their website and reach out to the moderator to request access to treatment. Since GS is not widely available, it’s very expensive. FIP Warriors provides a price calculator and GoFundMe pages to help. You can also check out their success stories and additional research studies. 

SOCK FIP is a non-profit organization. You can donate to their research-focused cause, read memorial stories, and access global FIP resources. 

Rainbows Bridge is an online pet memorial home. You can join a weekly candle-lighting ceremony, create a pet memorial of your own, and access a grief support center. 

Dante’s Story

If you’ve made it this far, please take another deep breath. Here’s the story of Dante, written by his amazing owner, Jess. Jess’s experience with FIP is heartbreaking to read, but if it helps at least one person out there, it’s worth every minute.

Dante

My fiancé and I originally decided we wanted to adopt an adult female cat. Right after my fiancé’s birthday, we scheduled a virtual cat meet-and-greet with the Lawrence Humane Society (this was during COVID’s peak). During the meet-and-greet, the consultant held up two little black kittens, one girl and one boy. We knew instantly we wanted the boy. It was just an unspeakable and unexplainable agreement between the three of us. His name was Bjorn and he was born on January 21, just a few months before. 

I went and picked up Bjorn myself. Because of COVID, I couldn’t come into contact with any of the associates at the humane society. So, when I arrived, Bjorn was waiting outside for me in a box. Once I grabbed it, got back in my car, and opened it, I sobbed my head off. I couldn’t and still can’t explain it, but I just knew he was going to be so big in my life. I loved him so much already! 

We named him Dante the day we brought him home, but he eventually became known as Bubby. We both worked from home, so we spent 24/7 with him and we all grew VERY attached to each other. He was so, so playful, sweet, snuggly, and clever. I’ve never seen a cat hunt so well.

He had the most interesting sounds! He whined, mouth closed, like a dog. And when he meowed, it sounded like, “Mmm, oh wow!” Sometimes he would get a toy stuck somewhere, come up to me, and then whine until I’d go fix it. 

Dante had a beautifully unique personality. He would ask to be held by putting his front beans on our shoulders and then lifting his legs. He slept on our pillows every night. His favorite show was “Meerkat Manor,” and he loved watching the meerkats run around and hunt. Dante was a master at stealing food: eggs, potatoes, full chicken breasts…ugh.

Dante’s signs of FIP

We went out of town to adopt our newest baby, Tosca, who is named after the meerkat Dante had a little crush on. When we got back, we noticed that he looked huge. He was easily five or six pounds heavier! We thought maybe the pet sitter had just overfed him because other than that, he seemed perfect. 

One day later, I noticed his third eyelid was showing in each eye, and he was acting lethargic. He also had diarrhea that same night. We took him to the vet where we were told it was likely just an eye infection, so he was prescribed steroid eye drops and an antibiotic. His eyes cleared up instantly and we were feeling super optimistic. But, by the next evening, one of his eyes looked a little cloudy and he didn’t eat his dinner. 

This was extremely unusual for him. He ALWAYS scarfed down food. When we woke up the next morning, the eye that was cloudy was completely white and he had no vision in it. 

Dante’s diagnosis

When we got in to see our regular vet, he came in, looked at Dante, and immediately sat down. He told us he felt confident Dante had something called FIP. We had never heard of it. We instantly asked, “Okay, so what’s the plan? Another antibiotic?” It was then that our vet told us what FIP is. 

He told us there was no treatment other than an unapproved drug on the black market. The treatment was still being studied and was extremely expensive. “Regardless, this will be the thing that ends Dante’s life,” he said. It felt like the wind had been knocked out of us. Dante was our whole entire world.

Dante had a mix of wet and dry FIP. Overall, his symptoms were sudden blindness, lethargy, fever, diarrhea, a swollen/fluid filled abdomen, and loss of appetite. 

Dante’s options

Dante showed his first symptoms and passed away within about 3 or 4 days. His FIP progressed rapidly and severely. 

We felt we had no options at the time. Medical treatment was still being studied, was mostly inaccessible, and was way too expensive. Because of Dante’s type of FIP, it’s likely he would’ve needed intense treatment. 

We knew our best option was to help him pass on. He was in tons of pain, blind, and simultaneously starving while unable to eat. It was the worst thing either of us have gone through, but in Dante’s final moments, he let us know he was ready to go. 

We received Dante’s ashes and while we will cherish them forever, we wish we would have donated his body to FIP research. FIP is one of the most studied and least understood feline conditions, and if we had been able to slow down at the time, I think we would’ve chosen to honor Dante by helping vets understand what happened to him.

Honoring Dante

Now you know what signs of FIP to look for, and hopefully you also know that you are not alone in this. 

Your relationship with your kitty is your superpower and ultimately how you can detect FIP in its early stages. You know your cat. If something seems off, take them to the vet. Don’t be afraid of demanding answers. 

If love was enough to keep them here, we’d never lose our pets. One of the hardest parts of Dante’s passing was the feeling that all the incredible and intense love we had for him had nowhere to go. Eventually, we figured out that finding ways to honor him let that love, and his memory, live on. To this day, even in our new home, we put up his hammock each morning. We still kiss his collar, celebrate his birthday, and talk to our other cats about him. For the longest time, we slept with his collar on our pillows. Even his paw prints are still on our mirrors and TVs. He may be gone, but he’s still very much here. 

We love you forever, Dante.

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Disclaimer: The information here is based on my second-hand experience, conversations with veterinarians, research articles, and the first-hand experiences of those who have been through their own FIP journey. Take your cat to a trusted veterinarian immediately if your cat is showing signs of illness.

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