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Feline Infectious Peritonitis

Feline infectious peritonitis (inflammation of the lining of the abdomen) is a viral disease triggered by feline coronavirus (FCoV) which carries a high mortality, often fatal. It is the number one cause of death in cats in developed countries. This disease exploits weakened and immature immune systems, spreading by way of white blood cells (WBCs) as they circulate through the body. It is most often spread through inhalation of airborne contaminants and infected feces. The highest incidence is seen between 3-16 months of age with over half being under 1 year. It is comparatively higher in multi-cat households versus a single cat home. There are two forms: wet (effusive), which targets the body cavities and dry (non-effusive), which targets organs. The wet form tends to progress more rapidly but both suffer becoming increasingly lethargic. 




  • persistent and unresponsive fever

  • lack of appetite

  • weight loss

  • diarrhea

  • swelling of the abdomen

  • accumulation of fluid in the chest

  • difficulty breathing

  • sneezing/runny nose

  • lethargy




  • poor growth in kittens

  • anemia

  • jaundice

  • diarrhea

  • fever

  • depression

  • inflammation of the eye

  • neurological symptoms (loss of vision, loss of ability to coordinate movements)



It is difficult to diagnose because it can mimic other disease and there is no one laboratory test for it. A CBC can be done looking at WBC, but this only indicates an infection is present not which infection. An ELISA or IFA test shows the presence of coronavirus antibodies, but cannot distinguish the type or the cause of the condition, only that the cat has been in contact with the virus and produced antibodies to it. A biochemistry profile may be tested including a polymerase chain reaction (PCR), which can differentiate the unique DNA of FIP, but again only showing that it is coronavirus and not which type. A fluid sample from the abdomen or chest cavity may be needed for further evaluation. In more difficult cases surgery may be required to aid in diagnosing. The best approach is to rule out any other infection or disease and conclude based on symptoms.


The overall prognosis is poor. There is no effective treatment for the effusive form as it spreads too quickly. For the non-effusive form treatment is based on symptoms and just to make the last bit of life comfortable maybe prolonging life. Treatment (not a cure) may include antibiotics, anti-inflammatory, and immunosuppressive drugs. Removing fluid to eliminate pressure may be helpful.


Once a cat is diagnosed there is no need to quarantine. However, it is essential to isolate new litters from other cats (not including the mother). Pet owners should restrict indoor cats from going outside.



Article by Ron Hines DVM PhD 


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