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Wet FIP (Effusive): Symptoms, Fluid Buildup, and Diagnosis

Wet FIP: Understanding the Fluid and the Virus

For many cat owners, Wet FIP (Effusive FIP) appears seemingly overnight. You might notice your cat losing weight along the spine, yet their belly seems to be growing larger and tighter.

This contradiction—a skinny cat with a large belly—is the hallmark of Wet FIP. Understanding what is happening inside your cat’s body is the first step toward helping them fight back.

What Actually Happens in "Wet" FIP?

Feline Infectious Peritonitis (FIP) is caused by a mutation of the feline coronavirus. In the "Wet" form, the cat’s own immune system reacts too aggressively to the virus.

This reaction attacks the blood vessels, causing vasculitis (inflammation of the blood vessel walls). Imagine a garden hose with tiny pinpricks along it; the water leaks out. Similarly, your cat’s blood vessels become "leaky," allowing protein-rich fluid to escape into the body cavities.

Recognizing the Symptoms

​Wet FIP progresses faster than the Dry form. Early detection is critical.

  • Abdominal Effusion (Ascites): The most distinct sign. The abdomen distends and feels fluid-filled (like a water balloon), not hard like a food-bloat.

  • Thoracic Effusion (Fluid in Chest): Less visible but more dangerous. If fluid fills the chest cavity, it compresses the lungs. Watch for rapid breathing, panting, or labored breaths.

  • Weight Loss: Despite the heavy belly, you will feel the spine and hip bones becoming prominent.

  • Persistent Fever: A fever (usually over 39.5°C) that fluctuates and does not go away with standard antibiotics.

  • Pale or Yellow Gums: Anemia or Jaundice (liver involvement) often accompanies the fluid.

2 cat lay down on the bed one of it have a huge abdomen that spot a FIP wet form sign

Feline infectious peritonitis(FIP) wet form: Noticeable abodominal selling in a cat

How is Wet FIP Diagnosed?

Because fluid is present, veterinarians can usually diagnose Wet FIP quickly using these methods:

  • Fluid Analysis (The Rivalta Test) Your vet will draw a small sample of the fluid. FIP fluid is typically straw-yellow, clear to slightly cloudy, and sticky. They will perform a Rivalta Test—a simple chemical reaction. If the drop of fluid holds its shape like a jellyfish in the mixture, it is positive for FIP.

Rivalta test positive. A blue liquid has a shape like Jelly fish falling in testing tube.

Rivalta Test show positve(the liquid have a shape like jelly fish) 
(Ref. Author Kalumet from Wikipedia)

  • ​​Blood Chemistry (A:G Ratio) Blood tests often show high Globulins (due to the immune fight) and low Albumin. Veterinarians look at the Albumin to Globulin (A:G) ratio.

    • A:G < 0.6: Highly indicative of FIP.

    • A:G > 0.6: FIP is unlikely.

Blood Test Result From Central Lab

Example: Blood Chemisrty from VET CENTRAL LAB

  • X-rays: To identify what is in abdomen

Feline X-rays film, show full of fluid in cat abdomen

X-Ray flim Show full of fuid in abdomen

  • FCoV/FIP Rapid test kit: Make sure sample is a blood to fluid as you can see. The blood show positive but fluid show negative.

FCoV Test Kit Detect Positive FIP

FCoV Test Kit Show Positive

  • RT-PCR (Real Time Polymerase Chain Reaction)

FIP_PCR_TEST.jpg

RT-PCR From Central Lab Show Positive sign

GS-441524 is an antiviral medication indicated for the treatment of FIP in cats.

Preventing FIP

  • Stress Reduction: Create a calm and safe environment for your cat. This point is they best way but cat owner need to observe your cat and seek which acvitities that trgger their cat mood.

  • Good Hygiene: Regularly clean litter boxes and your cat's belongings.

Conclusion:

FIP can be a serious concern, but with knowledge and preparation, you can safeguard your cat's health. Consult with our team for personalized advice and support tailored to your cat's specific needs.

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