FIP in Cats: What It Is, Signs to Watch For, and Today’s Life-Saving Treatments
Published On: 12/23/2025
Last Updated On: 12/23/2025
By Callie, Seymour, Yebba, and Mama and our Hooman Ashley!
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Some topics make us curl our tails a little tighter around our hearts. This is one of them.
If you’ve ever heard the words “Your cat might have FIP,” you know the air changes instantly. The room feels smaller. The clock gets louder. Your mind races ahead to places you didn’t want to visit today.
We’re here to slow that moment down.
Because while FIP used to feel like a dead end, that story is changing — and cat parents deserve to know that hope is real, tangible, and growing.
What Is FIP in Cats?
FIP stands for Feline Infectious Peritonitis. It’s a disease caused by a mutation of the feline coronavirus — a virus many cats carry without ever becoming sick.
In a small number of cats, that virus mutates inside the body and triggers an intense inflammatory response. That inflammation can affect the abdomen, chest, brain, eyes, or other organs.
It’s not contagious cat-to-cat in its FIP form. It’s not caused by anything you did wrong. And it doesn’t mean your cat wasn’t strong enough.
It means biology took a cruel turn — and science is now fighting back.
Common Signs of FIP to Watch For
FIP doesn’t always announce itself loudly at first. Sometimes it whispers.
Early signs can include:
Lethargy or hiding more than usual
Decreased appetite or weight loss
Persistent fever that doesn’t respond to antibiotics
Poor coat quality
Behavioral changes
As the disease progresses, symptoms may depend on the type of FIP:
Fluid buildup in the abdomen or chest
Swollen belly
Difficulty breathing
Neurological symptoms (wobbliness, seizures)
Eye inflammation or vision changes
Organ-related symptoms depending on where inflammation occurs
If something feels off, trust that instinct. Cat parents know.
The Part We Need You to Hear: FIP Is Treatable Now
This is where the story shifts.
For years, FIP was considered fatal. Period. No footnote. No alternate ending.
Today, that’s no longer true.
Antiviral medications — most commonly GS-based treatments — have shown incredibly high success rates, especially when started early. Many cats go on to live full, healthy lives after treatment.
Treatment typically involves:
Daily antiviral medication (oral or injectable)
A treatment course around 84 days
Close monitoring by a veterinarian
Supportive care as the body heals
It is not always simple. It can be emotionally exhausting. It can be expensive. But it is possible — and thousands of cats are proof.
Diagnosis Isn’t Always Straightforward (And That’s Okay)
There is no single definitive test for FIP.
Diagnosis is often based on:
Bloodwork trends
Imaging (ultrasound, X-rays)
Fluid analysis (when present)
Clinical signs and response to treatment
This can feel frustrating and scary. It can feel like walking through fog.
You’re not imagining that — it is hard. And you’re allowed to ask questions, seek second opinions, and advocate loudly for your cat.
What to Do If You Suspect FIP
Seek veterinary care immediately
Ask direct questions about FIP
Request referrals or consults if needed
Connect with reputable rescue networks or veterinary professionals familiar with current treatments
Take notes, breathe, and remember you are not alone
A Gentle Note From the Newsroom Cats
If you’re here because you’re scared — we see you.
If you’re here because you’re learning — thank you.
FIP is no longer a hopeless diagnosis. It’s a challenge, yes — but one that science, advocacy, and love are meeting head-on.
We’ll keep telling these stories. We’ll keep sharing what matters. And we’ll keep standing with cat parents through the hard parts — because that’s what community looks like.
Hope belongs here. Always.
🐾 Coming tomorrow on Stray Cat News
We traveled two hours away to East Stroudsburg, PA for something very important:
✨ stretching
✨ cats
✨ community magic
We attended Tina Wieland’s Cozy Cat Stretch at Cozy Kitty Café, and hoomans… it was cozy, grounding, heart-filling, and exactly what a winter body (and soul) needs.
From gentle movement to adoptable cats wandering the room, this experience reminded us why cat cafés + wellness + local creators = something really special.
Full recap coming tomorrow. Trust us — you’ll want to read this one. 💛
