Is It Really FIP or Just Symptoms of Another Disease? Check the Facts!

Feline Infectious Peritonitis (FIP) is a serious disease caused by a mutation of the Feline Coronavirus (FCoV). Most of the time, when pawrents are told that their cat has been diagnosed with FIP, feelings of sadness, fear, and anxiety immediately take over.

And that’s understandable. FIP spreads rapidly and aggressively. If the diagnosis is not done correctly and the cat receives treatment too late, the cat's life could be at serious risk.

But here's the catch: diagnosing FIP is not an easy task. That’s because many other diseases show symptoms very similar to FIP, making misdiagnosis highly possible.

So, what can you do to avoid misdiagnosis? Let’s find out together! The BasmiFIP India team has prepared everything you need to know in this article.

Why Is FIP Diagnosis Often Confusing?

Diagnosing FIP is considered difficult and confusing because the initial symptoms can resemble many other diseases. These symptoms include:

• Fever

• Vomiting

• Loss of appetite

• Weight loss

Moreover, as many already know, FIP is classified into four different types:

• Wet FIP

• Dry FIP

• Ocular FIP

• Neurological FIP

Each type has different clinical signs, which makes the diagnostic process even more complex.

The challenge increases if the cat is already suffering from comorbidities—other existing health conditions. These can confuse the vet even further when trying to pinpoint the real cause of the symptoms.

Why? Because the vet has to determine whether the symptoms are due to a mutation of the FCoV virus or are simply an extension of a disease the cat was already suffering from.

Why Accurate Diagnosis Is Essential for the Right Treatment

Just like with humans, proper diagnosis is the foundation of successful treatment. If a misdiagnosis occurs, the disease can linger—or worse, cost the cat its life.

For cats with FIP, an accurate and timely diagnosis is key to recovery. The sooner and more precisely FIP is diagnosed, the better the cat's chances of survival.

As of now, the most effective treatment for FIP is the antiviral drug GS-441524. At BasmiFIP India, this medication is given in doses tailored to:

• The type of FIP diagnosed

• The cat’s body weight

• The results of laboratory tests

That’s why an accurate diagnosis is crucial—so that GS-441524 can work as effectively as possible inside the cat’s body.

Symptoms That Often Lead to Misdiagnosis

Here are some common symptoms of FIP that also appear in many other illnesses—causing them to be frequently misdiagnosed:

• High fever

• Persistent vomiting

• Digestive problems, including diarrhea or constipation

• Loss of appetite

• Significant weight loss

• Fatigue, weakness, lethargy

• Swollen lymph nodes

Diseases Often Mistaken for FIP

Let’s go over the list of diseases that are frequently mistaken for FIP:

Toxoplasmosis

Caused by a parasite called Toxoplasma gondii, infected cats often show signs such as fever, appetite loss, lethargy, and seizures. Interestingly, lethargy and seizures are also symptoms found in neurological FIP—making this one of the most commonly confused cases. That’s why additional testing is essential.

FeLV (Feline Leukemia Virus)

Much like FIP, FeLV spreads through saliva, urine, and feces. It can even act as a trigger for the onset of FIP. Cats with FeLV may appear completely healthy for a long time before severe symptoms finally show.

FIV (Feline Immunodeficiency Virus)

FIV weakens a cat’s immune system, making them more vulnerable to other infections. Since it also affects multiple organs, FIV is often mistaken for FIP, even though the treatment paths are entirely different.

FPV (Feline Panleukopenia Virus)

Cats with FPV may show symptoms like fever, vomiting, diarrhea, and appetite loss—very similar to FIP. That’s why further tests and diagnostics are a must in suspected cases.

IBD (Inflammatory Bowel Disease)

IBD causes vomiting, diarrhea, and weight loss due to chronic inflammation in the gut. These symptoms can easily be mistaken for FIP—especially if FIP is affecting the digestive system.

Lymphoma

As the name suggests, lymphoma affects the cat’s spleen and lymph nodes. Like FIP, it causes internal organ inflammation, which makes diagnosis difficult—even for experienced vets.

Cancer

Yes, cats can also get cancer. And just like FIP, it can be life-threatening and must be treated immediately. However, the symptoms of cancer and FIP are remarkably similar—both causing fever, weight loss, lethargy, and refusal to eat.

Tests That Help Differentiate FIP from Other Diseases

To determine whether your cat truly has FIP or not, the vet must conduct several tests. So, what are they? Let’s go over them briefly:

Blood Test (CBC and Blood Chemistry)

The first and most common test is a Complete Blood Count (CBC) and blood chemistry panel. This gives the vet a general idea of the cat’s overall health.

Typically, they will look at:

• Albumin levels

• Globulin levels

• Red blood cell count

• White blood cell count

• The Albumin-to-Globulin (A/G) ratio

These indicators help determine the need for further testing.

Rivalta Test

This test is only performed to confirm wet FIP. It’s only applicable for cats that have swollen abdomens due to fluid buildup.

X-Ray and Ultrasound (USG)

These imaging tools help vets assess the condition of internal organs. They’re usually used to detect fluid accumulation, organ enlargement, or inflammation in the chest or abdomen area.

MRI (Magnetic Resonance Imaging)

MRI uses magnetic fields and radio waves to visualize soft tissues, including the brain, spinal cord, and blood vessels. It’s especially helpful in suspected neurological FIP cases.

Biopsy

A biopsy involves taking a small tissue sample from an organ or lymph node to be analyzed in a lab. However, due to high costs and slow results, vets rarely recommend this as a first choice.

When Should You Suspect It Might Not Be FIP?

If all tests have been done and results remain inconclusive, your cat can start a trial treatment using GS-441524.

To know the right dosage, consult BasmiFIP India through WhatsApp first for expert guidance.

If after two weeks your cat shows no improvement—or seems to reject the treatment—please contact your vet immediately for a follow-up evaluation.

The Role of Your Vet and Importance of Follow-Up Consultations

Seeing your usually energetic and affectionate cat suddenly become quiet and weak can be devastating. That’s why pawrents need the support and guidance of an experienced veterinarian.

With a proper diagnosis, you’ll be able to stand by your cat’s side throughout the treatment journey. Recovery can be long and exhausting—but you don’t have to go through it alone.

BasmiFIP India is always here to support you and answer any of your questions—even if you just need to talk about your worries.

After your cat has been diagnosed and has started treatment with GS-441524 (in the dose recommended by BasmiFIP India), don’t forget to do follow-up tests on days 30, 60, and 84.

These tests are important to track your cat’s recovery progress—and to check for signs that might point to a different illness.

Conclusion

FIP is a disease that shares many symptoms with other conditions, which makes accurate diagnosis challenging. That’s why a series of thorough tests is essential before confirming FIP.

Trust your veterinarian and the BasmiFIP India team to provide the best care and support for your beloved cat.