Some early signs of FIP can be subtle and may be mistaken for other health problems. FIP can present in different ways, and not every cat will have the same symptoms.
A. Wet FIP — Often Associated with Fluid Accumulation
1. An Enlarged or Swollen Abdomen
The belly may become noticeably larger while the rest of the body appears thin.
2. Fluid Around the Lungs or in the Chest
This can cause rapid or difficult breathing and may become more noticeable when a cat is resting.
3. Persistent or Recurring Fever
A fever that continues or repeatedly returns may be a sign that something is wrong.
4. Low Energy and Reduced Appetite
A cat may become less active, sleep more than usual, or show a significant decrease in appetite.
B. Dry FIP — Symptoms Can Be Less Obvious
1. No Obvious Abdominal Fluid or Swelling
A cat may not have a noticeably enlarged belly and may appear relatively normal at first.
2. Gradual Weight Loss
Some cats may lose weight over time despite continuing to eat.
3. Eye-Related Changes
Recurring inflammation of the eyes, changes in the appearance of the eyes, or unusual pupil responses can occur in some cases.
4. Neurological Changes
Some cats may develop tremors, difficulty walking, changes in coordination, or unusual responses to their surroundings.
5. Changes in Behavior or Activity
A cat may spend more time sitting or resting, interact less with people or other pets, or seem unusually withdrawn.
If your cat has ongoing low energy, poor appetite, unexplained weight loss, or recurring fever—especially when these changes persist or worsen—it’s important to contact a veterinarian and discuss whether FIP or other possible causes should be evaluated.
FIP can resemble other illnesses, so symptoms alone cannot confirm a diagnosis. Veterinary evaluation and appropriate testing are important when FIP is suspected.