Feline infectious peritonitis (FIP) is a disease caused by feline virus, which can be infected by cats of all ages, but mainly affects cats under 3 years old, especially cats aged 4-14 months. The disease mainly occurs in foster care, shelter, etc. and high-density breeding places where stray cats gather. The disease is typically endemic, with a wide range of morbidity. Once clinical symptoms appear, the mortality rate is high. The course of the disease is usually several weeks to several months, and it is rare to survive for several years.
FIP virus (FIPV) mutates from feline enteric coronavirus (FECV). FECV is ubiquitous around the world, and in multi-cat environments, most apparently healthy cats are infected by ingestion of feces or fecal contaminants and shed the virus in their feces. Kittens are usually infected at 9 weeks of age. In the initial stage of infection, the replication-competent FECV produces a large number of virus mutants capable of causing FIP, but only a few cats exposed to these mutant viruses develop FIP. The causes of FIP are complex and related to the cat’s genetic susceptibility, age at infection and various stressors encountered during infection, as well as the cat’s ability to clear the virus. From initial infection with FECV to the onset of clinical symptoms, the incubation period is as short as 2-3 weeks, but can also be several months, rarely several years. The mutation of FECV to FIPV, or the progression from subclinical to clinical disease, occurred during the incubation period.
Once a cat becomes ill, it is difficult to recover. Younger, wet cases had a shorter course of disease than older, dry cases. Some wet cases can also survive for several months. The results of one study showed that most cats with relatively mild non-exudative FIP had a 1-year survival rate of only 5%.
Before the symptoms of FIP are discovered, the owner and the cat have already established a deep relationship. Most people find it difficult to accept the diagnosis that the cat has FIP with a high mortality rate and cannot be treated, especially for those cats who are in good health at the beginning of the diagnosis. . Owners hope to find more sensitive and specific diagnosis and treatment methods, but the results are often suboptimal or more confusing. Since there is no cure, some owners will look for solutions through the Internet or other channels.
In recent years, with the improvement of the understanding of FIP, some great progress has been made in the diagnosis and treatment, but there is still no particularly simple prevention method, and there is no simple diagnosis method and effective treatment method.
Diagnostic tests for FTP
Diagnosing FIP begins with consideration of the cat’s age, origin, clinical signs, and physical examination results. FIP should be considered in cats aged 4-36 months from high-density housing with persistent high fever and in response to antibiotic therapy. Except for FIP, other diseases rarely have such symptoms. The characteristic symptoms found by the owner’s observation or physical examination are helpful for the diagnosis of this disease. In cases of non-exudative (dry) or exudative (wet) FIP, common clinical symptoms include bloating due to ascites, dyspnea due to pleural effusion, jaundice, hyperbilirubinuria, renal mass/swollen mesenteric lymph nodes , uveitis, and neurological symptoms associated with the brain/spinal cord. Based on this reasonable certainty, an initial diagnosis of FIP can be made. But due to the high mortality rate of the disease, both veterinarians and pet owners are wary of making a diagnosis of this “reasonable certainty” and hope for further confirmation. Laboratory inspections are required for this purpose, including indirect and direct tests.