Symptoms2026-03-09Carelogy編集部
Feline Infectious Peritonitis (FIP): Latest Treatment, Symptoms & Prevention
Complete guide to FIP in cats: symptoms, wet vs dry forms, latest antiviral treatments (GS-441524), and prevention. Vet-supervised.
The Bottom Line: FIP Is No Longer a Death Sentence
Feline Infectious Peritonitis (FIP) was once considered universally fatal, but that is changing fast. The antiviral drug GS-441524 has made successful treatment a real possibility, with remission rates exceeding 80% in some studies. The key is catching it early — the sooner treatment begins after onset, the higher the chance of remission. FIP predominantly strikes young cats under 2 years old, and multi-cat households face elevated risk due to the higher prevalence of feline coronavirus in those environments.
The Two Forms of FIP and Their Symptoms
Wet (effusive) FIP: Fluid accumulates in the abdomen or chest cavity. Classic signs include a distended belly, labored breathing, loss of appetite, and persistent fever. This form tends to progress rapidly.
Dry (non-effusive) FIP: Granulomas form on internal organs. Symptoms vary depending on which organs are affected and may include eye inflammation (uveitis), neurological signs like wobbliness or seizures, and enlarged liver or kidneys. Dry FIP is harder to diagnose and progresses more slowly.
Both forms share common red flags: a persistent fever that does not respond to antibiotics, weight loss, and lethargy. If your cat has an unexplained, lingering fever, FIP should be on the list of possibilities to investigate.
What Causes FIP and How It Spreads
FIP develops when the feline coronavirus (FCoV) mutates inside an individual cat's body. FCoV itself is extremely common — in multi-cat households, 80–90% of cats carry it — and usually causes nothing more than mild diarrhea. However, in roughly 5–10% of infected cats, the virus mutates into the form that triggers FIP.
How it spreads: FCoV is transmitted primarily through feces. Shared litter boxes are the main risk factor in multi-cat homes.
Cats at highest risk: Kittens and young cats under 2, purebred cats, cats living in crowded multi-cat environments, and cats under significant stress. Understanding these risk factors can help you take preventive steps.
Latest Treatments: GS-441524 and Molnupiravir
GS-441524: A metabolite of remdesivir, this antiviral blocks the FIP virus from replicating its RNA. An 84-day oral course has achieved remission rates above 80% in published studies. Regulatory approval as a veterinary drug is progressing in several countries.
Molnupiravir: Originally developed for COVID-19 in humans, molnupiravir has shown promising results against FIP as well. It is gaining attention as a more affordable alternative to GS-441524.
Cost: An 84-day treatment course typically runs $1,500–$6,000 (¥200,000–800,000), depending on the cat's weight and which drug is used. The price tag is steep, but compared to the era when FIP was considered untreatable, these drugs represent a remarkable breakthrough.
Prevention and Early Detection Tips
There is no guaranteed way to prevent FIP, but you can meaningfully reduce the risk:
- Keep litter boxes scrupulously clean (one per cat plus one extra, scooped daily)
- Avoid overcrowding in multi-cat households
- Minimize stress (learn to recognize signs of stress in cats)
- Watch young cats closely for persistent low-grade fevers or appetite loss
The most effective tool for early detection is regular health monitoring. Use the CatsMe app to log your cat's daily condition and spot subtle changes before they become serious. The earlier FIP is caught, the better the treatment outcomes.
兽医问「什么时候开始的？」你答得上来吗？
别让自己在诊室里手足无措。CatsMe自动记录每日健康评分，一键就能分享给兽医。
FIP猫伝染性腹膜炎コロナウイルス腹水猫の病気
