Vet Clinics Treating FIP

Wisconsin

Castlerock Veterinary Hospital

  • Address: 1214 South Oak Avenue, Marshfield, WI 54449
  • Phone: 715-389-1011
  • Email: castlerockvethosp@gmail.com

Illinois

Minnesota

Iowa

Vet clinics with * are partnered with Marshmallow's Mission, providing care kits for FIP diagnosed families.

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FAQ

What is FIP?
Feline Infectious Peritonitis also referred to as FIP is a serious viral disease caused by a specific mutation of the Feline Enteric Coronavirus also referred to as FECV. While FECV is very common and usually causes mild stomach issues, when it mutates inside a cat's body, it becomes FIPV, targeting immune cells and causing systemic inflammation.
Is FIP contagious?
FIP is not contagious to humans or dogs. It is strictly a feline disease and cannot infect humans or other animal species. FIP is not contagious but FECV can be.
What are the main types of FIP?
Wet FIP causes fluid accumulation in the abdomen or chest cavity, leading to a swollen belly or difficultly breathing. Dry FIP causes inflammatory lesions on internal organs, leading to organ dysfunction without significant fluid buildup. Ocular FIP affects the eyes, causing cloudiness, color changes or inflammation. Neurological FIP affects the central nervous system leading to unsteadiness, tremors or seizures.
What are the early warning signs?
Early warning signs can be subtle and easily mistaken for other illnesses. Watch for: Persistent or fluctuating fever that does not respond to antibiotics. Lethargy, hidden behavior or decreased energy. Sudden loss of appetite and weight loss. A distended "pot bellied" abdomen. Unsteady walking, head tilts or cloudy eyes.
How is FIP diagnosed?
Bloodwork: Vets are looking for high globulin levels, low albumin to globulin ratio, and elevated inflammatory markers. Fluid Analysis: Testing abdominal or chest fluid. Imaging: Ultrasound or X-rays to check fluid or organ lesions.
Can FIP be cured?
Yes! FIP is no longer a death sentence. Thanks to modern antiviral treatments like GS-441524, FIP has an estimated cure rate over 85-95% when treatment is started early.
What is GS-441524 and how does it work?
GS-441524 is an antiviral nucleoside analog. It works by targeting the FIP virus directly, stopping its ability to replicate inside the cat's cells. Allowing the cat's immune system to recover and clear the virus.
How long does FIP treatment take?
The standard research-backed protocol consists of 84 days of treatment: daily oral or injectable medication, 84 days of observation: monitoring cat off medication to ensure full remission with no relapse.
Can my veterinarian prescribe FIP medication?
Yes, in the United States and several other countries, veterinarians can legally prescribe oral and injectable GS-441524 through licensed pharmacies under FDA regulatory guidelines.
What should I do if my cat is diagnosed?
Consult your vet immediately. Discuss legally compounded oral GS-441524. Start treatment promptly. Early intervention dramatically improves survival rates. Monitor weight daily. Medication dosages are weight dependent and must be adjusted as your cat regains health and weight.

Research

What is FIP?

Feline Infectious Peritonitis aka FIP is a severe, immune-mediated viral disease affecting domestic and wild cats. FIP does not start as FIP. It begins as the Feline Enteric Coronavirus aka FECV, a common, highly contagious, and usually mild intestinal virus widespread in multi-cat environments. In roughly 5-10% of infected cats, the benign enteric coronavirus undergoes a specific in body mutation. This mutated variant is known as the Feline Infectious Peritonitis Virus. FIP generally presents in two main forms, Wet FIP and Dry FIP. Wet FIP is characterized by rapid fluid accumulation in the abdomen or chest cavity, causing swelling, lethargy, and breathing difficulty. Dry FIP is characterized by severe inflammatory lesions on internal organs, eyes, or the central nervous system.

The Science and Immunopathogenesis

Why is mutated FIP so dangerous compared to normal enteric coronavirus? Macrophage Tropism: While harmless FECV replicates in the gut cells, the mutated FIP gains the ability to infect and replicated inside macrophages and monocytes. Systemic Dissemination: Infected macrophages carry the virus throughout the circulatory system to blood vessels in the organs, eyes, and brain. Immune Complex Vasculitis: The cat's body mounts an intense immune reaction. The interplay between viral antigens and antibodies causes severe inflammation of the blood vessels, leading to fluid leakage or located granulomatous tumors.

How FIP is Cured

For decades, treatment was limited to supportive care and anti-inflammatory steroids that only temporarily delayed the outcome. Today, targeted antiviral therapeutics directly halt FIP in its tracks. GS-441524: A small molecule nucleoside analog that directly inhibits the viral RNA dependent RNA polymerase. By mimicking natural molecular building blocks, it halts FIP replication without harming host feline cells. GS-5734: A prodrug of GS-441524. Commonly administered intravenously or subcutaneously in clinical settings before transitioning to oral GS-441524. Alternative oral antivirals used primarily as secondary treatments for refractory cases or relapses. Standard protocols involve 84 days of continuous daily oral treatment, followed by a 84 day observation period to confirm full viral clearance. Veterinarians in the US can legally prescribe compounded, quality assured oral GS-4415324 directly through regulated compounding pharmacies like Stokes Pharmacy.

Key Peer Reviews Studies and Scientific Timeline

Seminal peer-reviewed articles defining the medical understanding, virology, and treatment of feline infectious peritonitis (FIP) include foundational clinical identification by Jean Holzworth (1963), viral characterization by Niels C. Pedersen, and modern therapeutic breakthroughs by Brian G. Murphy and Niels C. Pedersen.

Initial Discovery and Pathology

  • Holzworth J. (1963): "Feline infectious peritonitis." J Am Vet Med Assoc, 196:99-107. First clinical description of FIP as a distinct and fatal disease entity. [1]
  • Wolfe LG, Griesemer RA (1966): "Feline infectious peritonitis." Pathologia Veterinaria, 3(3):255-279. Established the core histopathologic and pyogranulomatous features of the disease. [1, 2]

Virology and Immunopathogenesis

  • Pedersen NC et al. (1981): "An enteric coronavirus infection of cats and its relationship to feline infectious peritonitis." Am J Vet Res, 42(2):268-277. Differentiated low-virulence feline enteric coronavirus (FECV) from the lethal FIP virus (FIPV) pathotype. [1]
  • Pedersen NC (2014): "An update on feline infectious peritonitis: Virology and immunopathogenesis." The Veterinary Journal, 201(2):133-141. Comprehensive peer-reviewed synthesis of macrophage tropism, mutations, and immune-mediated vascular damage. [1, 2]

Antiviral Therapeutics Breakthroughs

  • Murphy BG, Perron M, Murakami E, et al. (2018): "The nucleoside analog GS-441524 strongly inhibits feline infectious peritonitis (FIP) virus in tissue culture and experimental cat infection studies." Vet Microbiol, 219:226-233. Proved the efficacy of the parent nucleoside analog in halting FIPV replication. [1]
  • Pedersen NC, Perron M, Bannasch M, et al. (2019): "Efficacy and safety of the nucleoside analog GS-441524 for treatment of cats with naturally occurring feline infectious peritonitis." J Feline Med Surg, 21(4):271-281. Landmark clinical trial demonstrating high remission rates, transforming FIP from a universally fatal diagnosis into a curable disease. [1, 3, 4]