Types of FIP in Cats: Wet vs. Dry FIP

Feline Infectious Peritonitis (FIP) is a complex and often fatal disease caused by a mutated form of the feline coronavirus (FCoV). While FIP was once considered untreatable, breakthrough antiviral treatments have brought hope to cat parents across the world, including in the Philippines.

FIP presents in two major forms:

• Wet FIP (Effusive)

• Dry FIP (Non-effusive)

Understanding the key differences between these types is essential for timely diagnosis and effective treatment. Each form presents differently in terms of symptoms, disease progression, and diagnostic challenges.

What Is Wet FIP (Effusive)?

Wet FIP, also called effusive FIP, is the more common and more rapidly progressing form. It’s characterized by a build-up of fluid in the cat’s body cavities—most commonly the abdomen and/or chest.

Causes of Fluid Accumulation

In wet FIP, the immune system’s inflammatory response leads to leaky blood vessels, causing protein-rich fluid to accumulate in body cavities.

Common Symptoms of Wet FIP:

• Distended or bloated abdomen (due to abdominal effusion)

• Labored breathing (if fluid is in the chest cavity)

• Persistent fever that doesn’t respond to antibiotics

• Weight loss and lethargy

• Pale gums or jaundice

• Loss of appetite

The fluid is often straw-colored, viscous, and may be sampled by a vet for analysis.

Diagnostic Tip:

A positive Rivalta test on abdominal or thoracic fluid is often used as a supporting diagnostic tool for wet FIP, especially in resource-limited settings like many regions in the Philippines.

📍 Learn more about how FIP is diagnosed: 👉 FIP Diagnosis Guide

What Is Dry FIP (Non-effusive)?

Dry FIP, or non-effusive FIP, is harder to diagnose due to the absence of fluid buildup. Instead, the virus targets specific organs, forming granulomas (inflammatory lesions) in places like the liver, kidneys, eyes, brain, or lymph nodes.

This form tends to progress more slowly, and symptoms depend on which organs are affected.

Common Symptoms of Dry FIP:

• Enlarged lymph nodes

• Ocular inflammation (red eyes, cloudy eyes, sudden blindness)

• Neurological signs (seizures, tremors, difficulty walking)

• Liver or kidney dysfunction

• Chronic weight loss and inappetence

• Mild to moderate fever

In dry FIP, imaging (like ultrasound), bloodwork, and in some cases, biopsies, are needed for a confident diagnosis.

Key Differences: Wet FIP vs. Dry FIP

Feature	Wet FIP	Dry FIP
Fluid Accumulation	Yes (abdomen or chest)	No
Symptoms	Rapid bloating, breathing issues	Vague symptoms based on organs
Onset Speed	Rapid progression	Slow and chronic
Common in	Young cats, especially under 2	Slightly older or adult cats
Diagnosis	Fluid analysis, Rivalta test	Imaging, organ biopsy
Neurological Involvement	Rare at onset	More common

Both forms can overlap—some cats may start with wet FIP and develop dry FIP symptoms later, especially neurological or ocular involvement.

Diagnosis and Treatment: What to Know

Diagnosis

FIP can be challenging to diagnose definitively without invasive testing. Most vets rely on a combination of:

• Bloodwork (globulin levels, A:G ratio, anemia)

• Imaging (fluid detection, organ enlargement)

• FCoV antibody or PCR testing

• Clinical history and symptom pattern

For more guidance on diagnosing FIP in the Philippines, see our guide: 👉 FIP Diagnosis Support

Treatment

Thanks to antiviral treatments like GS-441524-based therapy, FIP is no longer a death sentence. Success rates are now above 85% when caught early and treated properly.

🌿 Learn more about treatment options and recovery: 👉 FIP Treatment Options

Common Cases in the Philippines

In the Philippines, wet FIP is more frequently diagnosed due to several regional factors:

• Higher incidence of multi-cat households

• Limited access to early FCoV testing

• Tropical climate and frequent stressors like transportation or overcrowding

Many rescues and foster homes have reported cases where wet FIP progresses quickly, especially in kittens. However, dry FIP cases with neurological symptoms are increasingly being recognized as awareness grows.

Early recognition and prompt treatment are key to survival, especially in resource-limited settings.

Final Thoughts: Recognizing the Type of FIP Saves Lives

Whether a cat develops wet or dry FIP depends on various factors, including immunity, viral load, and stress. Understanding the symptoms and progression of each form empowers owners to act quickly and seek evidence-based treatment.

With proper support, many Filipino cat owners have successfully reversed FIP symptoms and restored their cats to full health.

💊 Looking for trusted FIP medications and support in the Philippines? 👉 Visit our Shop for treatment options and expert guidance.