FIP in Cats: Australian Caregiver's Complete Guide

Your cat has FIP. Or your vet has just said the words "we suspect Feline Infectious Peritonitis", and you have been googling at 2am, reading old forum posts that all end in heartbreak.

FIP in Cats: Australian Caregiver's Complete Guide

Take a breath. Those old forum posts are out of date.

Thanks to GS-441524, Feline Infectious Peritonitis (FIP) is no longer a death sentence. Across Australia, New Zealand and the wider Oceania region, pawrents are watching their cats go from collapsed and barely eating to bouncing back to normal in 84 days. This guide is the foundation: what FIP actually is, how to spot it, how it is diagnosed, and what treatment looks like in 2025. Read it carefully, because with FIP, the speed at which you act genuinely moves the needle.

Quick Summary for Pawrents in a Hurry

• FIP is a viral disease caused by a mutation of Feline Coronavirus (FCoV). It is not contagious cat to cat in its FIP form.

• There are four clinical types: wet (effusive), dry (non-effusive), ocular, and neurological.

• FIP is clinically proven to be treatable. GS-441524 monotherapy has a 92% success rate (Pedersen et al., UC Davis, 2019). The dual antiviral protocol with GS-441524 plus EIDD-1931 capsules shows 78.3% remission (Li and Cheah, 2025).

• Standard treatment runs 12 weeks (84 days), followed by an observation period.

• Over 100,000 cats have been treated worldwide since 2019. You are not alone.

• Act fast, start treatment. Every day matters.

What Is FIP, in Plain English

Most cats in Australia and New Zealand carry Feline Coronavirus (FCoV) at some point in their lives. In the vast majority, it causes nothing worse than mild diarrhoea or no symptoms at all. The cat sheds the virus and moves on.

In a small percentage of cats, however, the virus mutates inside the body. That mutated form is what we call FIP. Instead of staying in the gut, the virus starts replicating inside immune cells called macrophages and triggers a runaway inflammatory response throughout the body.

That is the key point: FIP is not a contagion you catch from another cat with FIP. It is a mutation event inside one cat. Your other cats at home are not at high risk just because one cat in the household has been diagnosed.

Who gets it? FIP most commonly affects:

• Kittens and young cats under two years old

• Purebreds (Ragdolls, Bengals, British Shorthairs and others)

• Cats from multi-cat environments such as shelters, catteries and rescues

• Cats under stress (rehoming, surgery, vaccination, illness)

Older cats can develop FIP too, but the young, the recently rehomed, and the recently stressed are the highest risk groups Australian shelters and breeders see.

The Four Types of FIP, and How They Show Up

FIP does not look the same in every cat. Recognising the form your cat presents with is critical because dosing depends on it.

1. Wet (Effusive) FIP

This is the form most pawrents and vets recognise first because the changes are visible.

Key FIP symptoms in cats with the wet form:

• A swollen, fluid filled abdomen (often described as a "pot bellied" look)

• Laboured breathing if fluid builds in the chest cavity

• Lethargy and dramatic loss of energy

• Persistent fever that does not respond to standard antibiotics

• Poor appetite and weight loss despite the bloated belly

• Pale or yellow tinged gums

Wet FIP typically progresses fast. If your vet draws off straw coloured, slightly sticky fluid from the abdomen or chest, that is a strong clinical pointer.

2. Dry (Non-effusive) FIP

Dry FIP is the slow burn cousin and is harder to diagnose because there is no obvious fluid. The inflammation forms granulomas in internal organs instead.

Key symptoms:

• Persistent low grade fever, often cycling up and down

• Gradual weight loss and muscle wasting

• Reduced appetite over weeks

• Lethargy and hiding behaviour

• Jaundice if the liver is involved

• Enlarged lymph nodes

Many dry FIP cases are diagnosed late because the symptoms look like "just an off cat" for weeks before pawrents realise something serious is going on.

3. Ocular FIP

Ocular FIP affects the eyes and can occur on its own or alongside other forms.

Key symptoms:

• Cloudy eyes or a colour change in the iris

• Visible inflammation inside the eye

• Blood or pus in the front chamber of the eye

• Changes in pupil size or shape

• Sudden vision loss or bumping into furniture

Ocular signs require higher antiviral dosing than wet or dry, because the eye is a protected compartment the drug must penetrate.

4. Neurological FIP

Neurological FIP affects the brain and spinal cord and is the most challenging form to treat, though absolutely treatable when caught and dosed correctly.

Key symptoms:

• Wobbly, uncoordinated walking (ataxia)

• Seizures

• Head tilt or unusual head movements

• Behavioural changes, confusion, vocalising at night

• Partial paralysis or weakness in the back legs

• Incontinence

Like the eye, the central nervous system requires a higher dose to achieve effective drug levels.

How FIP Is Diagnosed in Australia and New Zealand

There is no single test that returns a tidy "yes, this is FIP" result. Diagnosis is what vets call a "puzzle piece" process, combining several findings.

Your vet will typically work through:

1. Clinical history and physical exam: age, breed, household, recent stressors, fever pattern.

2. Bloodwork: high globulin levels, a low albumin to globulin (A:G) ratio (often under 0.6), anaemia, elevated bilirubin, and signs of inflammation.

3. Fluid analysis (in wet cases): the fluid is usually pale yellow, high in protein and contains specific cell types consistent with FIP.

4. Imaging: ultrasound to look for fluid, organ changes, enlarged lymph nodes or granulomas.

5. PCR testing: FCoV PCR on fluid or tissue can support diagnosis. A positive PCR with consistent clinical signs is highly suggestive.

6. Rivalta test: a quick in clinic fluid test that can support a wet FIP diagnosis.

If your cat is showing neurological or ocular signs, MRI and ophthalmology assessment may be added.

Here is the practical part: a vet who tells you the diagnosis is "highly likely FIP" based on the puzzle pieces above is usually right, and treatment should not be delayed waiting for a perfect confirmation. With FIP, the cost of waiting is paid in your cat's body condition. Act fast, start treatment.

FIP Treatment in Australia: What Actually Works

For years, vets had nothing to offer FIP cats. That changed when GS-441524, a nucleoside analogue antiviral, was shown in the landmark Pedersen et al. study at UC Davis (2019) to bring 92% of treated cats into remission. Since then, over 100,000 cats worldwide have been treated, and the protocols have been refined for wet, dry, ocular and neurological forms.

GS-441524 is the hero ingredient behind CureFIP. It directly targets the viral replication machinery, shutting down the cycle that drives FIP's inflammation. Treatment runs for 12 weeks (84 days), every single day, without missed doses.

Injectable GS-441524: The Gold Standard for Severe Cases

For cats with significant illness, ocular involvement, or neurological signs, injectable GS-441524 remains the reference treatment. CureFIP Oceania stocks two concentrations to make dosing larger or smaller cats easier:

• GS-441524 Antiviral Injectable, 20mg/ml, 8ml at AU$79.00, available With B12 or Without B12.

• GS-441524 Antiviral Injectables, 30mg/ml, 8ml at AU$99.00, available With B12 or Without B12.

Dosing is by FIP type, per the Pedersen et al. UC Davis protocol (PMC6435921):

• Wet FIP: 6 mg/kg per day

• Dry FIP: 8 mg/kg per day

• Ocular FIP: 10 mg/kg per day

• Neurological FIP: 10 mg/kg per day

Schedule: one subcutaneous injection per day, 7 days a week, for 84 days. Your vet should confirm dose, recalculate as your cat regains weight, and monitor bloodwork along the way.

Oral Dual Therapy: For Suitable Wet and Dry Cases

For pawrents whose cats hate injections, or for cases where the disease profile suits an oral route, CureFIP offers the CureFIP Oral Capsules, Dual-Action Formula at AU$139.00. This combines GS-441524 with EIDD-1931 in a single daily capsule.

Weight banded dosing per the catalog:

• Under 2.5 kg: GS-441524 25 mg plus EIDD-1931 5 mg

• 2.5 to 5 kg: GS-441524 35 mg plus EIDD-1931 8 mg

• Over 5 kg: GS-441524 50 mg plus EIDD-1931 12 mg

One capsule per day, every day, for the recommended 12 weeks. The dual antiviral approach has shown 78.3% remission in published outcomes (Li and Cheah, 2025).

Important: oral dual therapy is positioned for wet and dry FIP. It is generally not recommended once ocular or neurological signs are present, or if your cat cannot eat or defecate. Those cases need the injectable route to achieve the higher doses required.

EIDD-1931 as a Standalone

EIDD-1931 Oral Capsules are also available at AU$39.00 per 60 capsule bottle, dosed at one 15 mg capsule per 2.5 kg body weight every 12 hours, for a standard 60 day course. EIDD-1931 is not for ocular or neurological cases, and not for cats that are not eating or defecating. It must not be used in pregnant or lactating queens. Your vet will guide whether and how this fits your cat's plan.

What Recovery Looks Like

Most cats start showing improvement within 1 to 2 weeks of starting GS-441524. The fever breaks, appetite returns, and energy starts coming back. That can feel miraculous, but the full 84 days of treatment is essential. Stopping early is the single biggest cause of relapse.

After day 84, your cat enters an observation period of around 12 weeks, with regular bloodwork to confirm remission is holding. Cats that clear that window are considered to be in long term remission and very often live full, normal cat lives.

Supportive care during treatment includes:

• High calorie, palatable food (warming wet food often helps)

• A quiet, low stress space at home

• Gentle hydration support if needed

• Regular weigh ins to keep doses accurate as your cat grows

Why Speed Matters

FIP damages organs while it runs unchecked. The earlier you start GS-441524, the less repair the body has to do afterwards, and the smoother the 84 days tend to be. If your vet has raised FIP as a possibility, do not spend a week waiting on a single confirmatory test if the clinical picture is already pointing there. Discuss starting treatment.

CureFIP Oceania exists for exactly this reason: to give Australian and New Zealand pawrents fast, reliable access to clinically proven GS-441524 protocols, with the dosing guidance and support that turns a terrifying diagnosis into a recovery story.

FAQ

Is FIP contagious to my other cats?

The underlying Feline Coronavirus (FCoV) is contagious between cats, mostly through shared litter trays, and most cats handle it without ever developing FIP. The mutated FIP form itself is not transmitted cat to cat in any meaningful way. Your other cats are not at high risk simply because one cat has been diagnosed, though good hygiene and stress reduction across the household always helps.

How much does FIP treatment cost in Australia?

Total cost depends on your cat's weight, the form of FIP, and whether you use injectables or oral capsules. As a starting point, GS-441524 Antiviral Injectable, 20mg/ml, 8ml is AU$79.00 and the 30mg/ml, 8ml version is AU$99.00. The CureFIP Oral Capsules Dual-Action Formula is AU$139.00. Your vet, together with CureFIP Oceania, can help you map out the full 84 day plan and how many vials or bottles your cat will need based on weight and FIP type.

How quickly will I see improvement after starting GS-441524?

Most pawrents report a noticeable change within the first 1 to 2 weeks: fever drops, appetite returns, and energy starts to come back. That early improvement is encouraging, but it is not the finish line. The full 84 day course must be completed to avoid relapse.

Can FIP come back after treatment?

Relapse is possible, especially if treatment is stopped early, under dosed, or the wrong dose was used for the form of FIP. With correctly dosed 84 day protocols and a clean 12 week observation period, the majority of cats achieve long term remission. The published figures are 92% success for GS-441524 monotherapy (Pedersen et al., UC Davis, 2019) and 78.3% remission for the dual GS-441524 plus EIDD-1931 protocol (Li and Cheah, 2025).

Do I need a vet to treat my cat with CureFIP products?

Yes. Veterinary supervision is essential throughout. Your vet confirms the diagnosis and FIP type, sets the correct dose for your cat's weight, monitors bloodwork during the 84 days, and guides the observation period afterwards. CureFIP Oceania supports you and your vet with the products, dosing references, and a community of pawrents who have walked this road and come out the other side with their cats beside them.