Feline Infectious Peritonitis (FIP) is a disease that is incurable and fatal for cats. The average life expectancy for cats with FIP is two months or less from the time of diagnosis.
In one study, half of the cats with FIP died within nine days. However, some cats may live for several months.
The wet form of FIP is fatal within about five weeks of diagnosis. The dry form is also dangerous, but cats that get it may live for a few months.
The “wet” form of FIP includes the effusion of thick, yellow fluid. The “dry” form is more insidious, leading to death over a much longer period.
FIP can damage your cat’s eyes or nervous system causing blindness and paralysis. In the wet form, fluid may build up in your cat’s tummy (causing swelling of the abdomen) or chest (causing difficulty in breathing).
Understanding Feline Infectious Peritonitis (FIP)
What is FIP?
FIP is a complex and poorly understood disease that results from a mutation of the FCoV, a common virus that usually causes mild or no symptoms in cats. FCoV is not the same as the coronavirus that makes people get COVID-19. FCoV is transmitted through fecal-oral contact, such as sharing litter boxes, food bowls, or grooming. Most cats infected with FCoV develop antibodies and clear the infection, but some cats may become chronic carriers and shed the virus intermittently.
In about 10% of infected cats, the FCoV mutates into a strain called FIPV (feline infectious peritonitis virus), which can invade and damage the cells of the immune system and various organs, such as the liver, kidneys, brain, and eyes. The mutation is influenced by genetic and environmental factors, and it occurs within the individual cat, not between cats. Therefore, FIP is not considered contagious, although FCoV is.
Causes of FIP
The exact cause of FIP is unknown, but it is thought that a combination of factors contributes to the development of the disease. These factors include:
- The genetic makeup of the cat and the virus: Some breeds, such as Persians, Abyssinians, Bengals, Birmans, Himalayans, Ragdolls, and Rexes, are more prone to FIP than others. Some strains of FCoV may be more likely to mutate into FIPV than others.
- The immune response of the cat: Some cats may have a defective or inappropriate immune response that allows the FIPV to spread and cause inflammation in the body. This may be related to the age, health, and stress level of the cat.
- The environmental conditions: FIP is more common in cats that live in crowded, stressful, or unsanitary environments, such as shelters, catteries, or multi-cat households. These conditions may increase the exposure to FCoV and the risk of mutation.
Risk factors
The risk factors for FIP include:
- Age: FIP is most frequent in young cats between 6 months and 2 years old, but it can occur at any age.
- Breed: As mentioned above, some breeds are more susceptible to FIP than others.
- Health status: Cats with weakened immune systems, such as those with feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), or other chronic diseases, may be more vulnerable to FIP.
- Stress: Stressful events, such as moving, surgery, vaccination, or illness, may trigger or worsen FIP in some cats.
- Exposure: Cats that have contact with other cats that are infected or shedding FCoV may have a higher chance of developing FIP.
Signs and Diagnosis of FIP
Signs of Wet and Dry FIP
FIP can manifest in two forms: wet (effusive) and dry (non-effusive). The wet form is characterized by the accumulation of fluid in the abdomen or chest, which causes swelling, breathing difficulties, and weight loss. The dry form is characterized by the formation of granulomas, which are nodules of inflammatory cells, in various organs, such as the liver, kidneys, eyes, and brain. The dry form may cause organ dysfunction, neurological signs, eye problems, and skin lesions. Some cats may have signs of both forms of FIP.
The signs of FIP are often vague and nonspecific, and they may vary depending on the organs affected. Some of the common signs of FIP include:
- Fever that does not respond to antibiotics
- Loss of appetite and weight
- Lethargy and depression
- Anemia and pale gums
- Jaundice (yellowing of the skin and eyes)
- Diarrhea and vomiting
- Difficulty breathing and coughing
- Abdominal or chest distension
- Seizures, paralysis, or behavioral changes
- Blindness, uveitis (inflammation of the eye), or retinal detachment
How FIP is Diagnosed?
FIP is difficult to diagnose because there is no definitive test for the disease. The diagnosis is based on a combination of clinical signs, history, physical examination, laboratory tests, and imaging. Some of the tests that may be performed include:
- Blood tests: These may show anemia, elevated globulins (a type of protein), low albumin (another type of protein), and high liver enzymes. However, these findings are not specific to FIP and may be seen in other conditions.
- FCoV antibody test: This test measures the level of antibodies against FCoV in the blood. However, this test cannot distinguish between FCoV and FIPV, and it cannot predict whether a cat will develop FIP or not. A positive result means that the cat has been exposed to FCoV, but it does not mean that the cat has FIP. A negative result means that the cat has not been exposed to FCoV, but it does not rule out FIP.
- FCoV PCR test: This test detects the genetic material of FCoV in the blood, feces, or fluid samples. However, this test also cannot distinguish between FCoV and FIPV, and it may give false positive or negative results. A positive result means that the cat is infected or shedding FCoV, but it does not mean that the cat has FIP. A negative result means that the cat is not infected or shedding FCoV, but it does not rule out FIP.
- Fluid analysis: This test examines the fluid from the abdomen or chest for its appearance, protein content, and cell types. The fluid in FIP is usually yellow, cloudy, and sticky, and it has a high protein level and a high number of white blood cells. However, these characteristics are not exclusive to FIP and may be seen in other diseases.
- Biopsy: This test involves taking a sample of tissue from an affected organ and examining it under a microscope. This is the most definitive way to diagnose FIP, but it is also the most invasive and risky. The biopsy may show the presence of granulomas and FIPV within the cells.
Treatment and Prognosis for FIP
Options for Treatment
There is no cure for FIP, and the treatment is mainly supportive and palliative. The treatment aims to relieve the symptoms, improve the quality of life, and prolong the survival of the cat. Some of the treatment options include:
- Fluid therapy: This may help to correct dehydration, electrolyte imbalance, and anemia.
- Diuretics: These may help to reduce the fluid accumulation in the abdomen or chest and ease breathing.
- Anti-inflammatory drugs: These may help to reduce the inflammation and pain caused by FIP. Corticosteroids are the most commonly used drugs, but they may have side effects, such as increased appetite, thirst, urination, and susceptibility to infections. Non-steroidal anti-inflammatory drugs (NSAIDs) may also be used, but they may cause gastrointestinal ulcers or kidney damage.
- Antibiotics: These may help to prevent or treat secondary bacterial infections that may complicate FIP.
- Immunosuppressive drugs: These may help to suppress the immune system and reduce the inflammatory response to FIP. However, they may also increase the risk of infections and other complications. Cyclosporine and interferon are some of the drugs that have been used, but their efficacy and safety are not well established.
- Antiviral drugs: These may help to inhibit the replication of FIPV and slow down the progression of the disease. However, there are no approved antiviral drugs for FIP, and the ones that have been used experimentally are expensive, toxic, and of limited availability. GS-441524 and GC376 are some of the drugs that have shown promising results in clinical trials, but they are not commercially available and their use is restricted by legal and ethical issues.
- Nutritional support: This may help to maintain the body weight and condition of the cat. A high-quality, highly digestible, and palatable diet is recommended, and supplements such as omega-3 fatty acids, vitamins, and antioxidants may be beneficial. Feeding tubes may be needed in some cases.
- Symptomatic treatment: This may help to address specific signs or complications of FIP, such as seizures, eye problems, or skin lesions. Anticonvulsants, eye drops, or topical creams may be prescribed as needed.
Prognosis for Cats With FIP
The prognosis for cats with FIP is poor, and most cats die within weeks or months of diagnosis. The survival time depends on the form, severity, and progression of the disease, as well as the response to treatment. Some cats may live longer than others, and some may even go into remission, but these are rare exceptions.
Euthanasia may be considered when the quality of life of the cat is severely compromised by the disease. The decision to euthanize a cat with FIP is a difficult and personal one, and it should be made in consultation with the veterinarian and the owner’s wishes.
Prevention and Control Measures
There is no vaccine for FIP, and the prevention and control of the disease are challenging. However, some measures that may help to reduce the risk of FIP include:
- Testing and isolating cats that are infected or shedding FCoV, especially in multi-cat environments. However, the tests are not reliable and may not reflect the true status of the cat.
- Reducing the exposure to FCoV by maintaining good hygiene, sanitation, and litter management. Cleaning and disinfecting the litter boxes, food bowls, and other items that may be contaminated with feces regularly. Use disposable litter and avoid clay or clumping litter that may stick to the paws and fur of the cat.
- Reducing the stress and overcrowding of cats by providing adequate space, resources, and enrichment. Avoid introducing new cats or changing the environment frequently. Providing a calm and comfortable environment for the cat.
- Boosting the immune system of the cat by feeding a balanced and nutritious diet, avoiding unnecessary vaccinations or medications, and treating any underlying health problems promptly.
- Consulting the veterinarian regularly and monitoring the health and behavior of the cat closely. Seeking medical attention as soon as possible if any signs of FIP are noticed.
