Feline Infectious Peritonitis FIP Causes and Treatments for Cats

Feline Infectious Peritonitis
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FIP is caused by a virus and can be fatal to cats. Learn how to prevent FIP.

Feline Infectious Peritonitis -- or FIP -- is a viral infectious disease that affects wild and domesticated cats around the world. The disease is caused by certain strains of a virus called the coronavirus. Most strains of the coronavirus do not cause disease, but in a small percentage of affected cats the virus may progress into clinical FIP, which can be fatal. Here we’ll look at the causes, symptoms, and treatment of FIP in cats.


FIP is caused by certain strains of a virus called the coronavirus. Most strains of the coronavirus do not cause disease, but in certain cases the virus may progress into clinical FIP either through mutation of the virus or a compromised immune system. White blood cells become infected with the virus, and then those cells carry the virus throughout the cat’s body. As these cells enter different parts of the cat’s body such as the brain, kidneys, or abdomen, an inflammatory reaction occurs in the tissues where the infected cells congregate. This interaction between the cat’s immune system and the virus is what ultimately causes the disease.

FIP is more common in young cats that are two years old or younger.


Cats who have been exposed to the coronavirus often show no symptoms, though some may show upper respiratory symptoms such as runny nose, watery eyes, and sneezing. Other cats may experience diarrhea. Only a small percentage of cats with the coronavirus will develop FIP, but those that do will exhibit different symptoms depending on if they have the “wet” or “dry” form of the disease.

Symptoms Seen in Both Forms

  • Fever that doesn’t respond to antibiotics
  • Anorexia
  • Weight loss
  • Lethargy

Symptoms Seen in “Wet” Form

  • Fluid accumulates in the abdominal cavity, chest cavity, or both
  • Cats with fluid in the chest may exhibit labored breathing
  • Cats with fluid in the abdomen may show a progressively distending abdomen (or pot belly)

Symptoms Seen in “Dry” Form

  • Inflammatory cells (or granulomas) form in various organs, and the symptoms will depend on which organ is affected
  • Excessive thirst, urination, vomiting, and weight loss is seen if the kidneys are affected
  • Jaundice is seen if the liver is affected
  • The eyes and neurological system can also be affected


Your vet may drain and examine any fluids in the chest or abdominal cavity; if these fluids are straw-colored, it's likely that the cat has FIP. In more than 95% of cases, Feline Infectious Peritonitis is fatal. There is no known cure at this time. In most cases, treatment of FIP is purely supportive to make the cat more comfortable while they are still alive. Inflammatory responses are often alleviated with corticosteroids, cytotoxic drugs, and antibiotics. Other supportive treatment includes blood transfusions, fluid therapy, and draining accumulated fluids.

Protect Your Cat From Feline Infectious Peritonitis

You can help to protect your cat from developing FIP by limiting exposure to infectious agents. Keep litter boxes, food bowls, and water bowls clean and separate. Staying current with your cat’s vaccinations, avoiding too much contact with unfamiliar cats, and providing proper nutrition can also help your cat to stay healthy. An intranasal vaccine to prevent FIP has been developed, but it is not recommended by the American Association of Feline Practitioners Feline Vaccine Advisory Panel.

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This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.

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