FIP (Feline Infectious Peritonitis)
I recently started a cat podcast called Hiss and Tell: Cat Behavior and Beyond. One of the most requested topics was FIP, Feline Infectious Peritonitis. While I don’t normally write about feline health issues here (I am a behaviorist, not a veterinarian), FIP stands as one of the most perplexing and devastating diseases affecting domestic cats worldwide and is worth discussing. With its elusive nature and often fatal outcomes, FIP poses a significant challenge to veterinarians, researchers, and cat owners alike. If reading a bunch of text about FIP isn’t to your taste, you can also watch the full episode of the podcast here, below!
FIP is caused by a feline coronavirus (FCoV), which primarily affects the gastrointestinal tract. Most cats infected with FCoV exhibit mild or no symptoms, and the virus is shed in feces, allowing for easy transmission among cats, particularly in multi-cat environments such as shelters. However, in a small percentage of cases (approximately 5-10%), FCoV mutates within the cat's body, leading to the development of FIP. Stress has been shown to play a role in disease development. Most effected cats are young, with the disease being almost unheard of in adult or geriatric cats.
FIP manifests in two distinct forms: the effusive (wet) form and the non-effusive (dry) form. In the effusive form, fluid accumulates in body cavities such as the abdomen or chest, leading to symptoms such as abdominal distension, difficulty breathing, and lethargy. Conversely, the non-effusive form presents with a wide array of symptoms, including fever, weight loss, jaundice, neurological abnormalities, and organ dysfunction. These symptoms can vary widely among affected cats, complicating the diagnosis process.
Diagnosing FIP can be difficult due to its varied and nonspecific symptoms and the lack of a definitive diagnostic test. Veterinarians typically rely on a combination of clinical signs, laboratory tests (such as bloodwork and imaging, PCR testing, etc), and occasionally biopsy samples to make a diagnosis. However, even with these diagnostic tools, confirming FIP remains elusive in some cases.
Historically, treatment options for FIP have been limited, with supportive care being the mainstay of management. This includes fluid therapy, nutritional support, and medications to alleviate symptoms such as inflammation and pain. In recent years, several experimental treatments have emerged, including antiviral drugs, immunomodulators, and monoclonal antibodies. While these treatments have shown promise, their efficacy remains variable, and they are not widely available. However, most cat owners ARE able to gain access to these treatments via a robust “black market” that has popped up on social media via FIP groups who support one another. Over 90% of treated cats go on to make a recovery, although some must be on medication for life.
The complex nature of FIP has spurred intensive research efforts aimed at unraveling its mysteries and developing effective treatments. Scientists are exploring various strategies, including understanding the mechanisms of FCoV mutation, identifying biomarkers for early detection, and developing novel antiviral agents. Additionally, advances in immunology have led to investigations into enhancing the cat's immune response to FCoV, potentially preventing the development of FIP altogether.
FIP remains a formidable foe in the realm of feline medicine, challenging veterinarians and researchers to find solutions to its devastating effects. While progress has been made in understanding the disease and exploring treatment options, much remains to be done. Continued collaboration between scientists, veterinarians, and cat owners is essential in the quest to conquer this enigmatic disease and improve the health and well-being of our feline companions.