Pathogenesis of Feline Infectious Peritonitis (FIP) - the infection of the monocyte

The key event in the development of feline infectious peritonitis (FIP) is the infection of the monocyte (a white blood cell) by feline coronavirus (FCoV). From the moment of infection of the monocyte, the cat's fate hangs on whether or not that monocyte can contain the virus and eventually defeat it, or whether the virus wins, and begins replicating within the monocyte. In this animation, we depict the latter. We show how the virus hijacks the immune system, leading to an inflammatory sequence of events which results in a pyogranuloma forming around a blood vessel. In the film we show the development of acute FIP, where there is a lot of virus, many blood vessels affected, and the resulting leakage from damaged blood vessels causes the clinical signs of effusive FIP -- ascites, thoracic effusion, pericardial effusion. In non-effusive FIP the course is more chronic: fewer blood vessels are affected, the cat's immune system tries harder to contain the infection, leading to larger pyogranulomata and the clinical signs of chronic inflammation and relating to the organ(s) containing the pyogranulomas. The catvirus.com website and You Tube channel are mainly aimed at postgraduate veterinarians and undergraduate veterinary students, to supply information which is difficult to source elsewhere and to enable free online continuing professional development. Non-veterinarians can find resources suitable for all cat lovers.at my website, www.catvirus.com. Dr Diane D. Addie is a ...

Feline infectious peritonitis (FIP) is a leading infectious cause of death in the cat, especially affecting purebred cats and cats in rescue environments anywhere a lot of cats are kept indoors. No matter what any laboratory or manufacturer of test kits claims, there is no single test for FIP diagnosis is a challenge to even the most competent veterinary clinician and involves following a series of steps on an algorithm (free to download from www.catvirus.com). FIP can present as effusive (wet) or non-effusive (dry). This film shows one step in the work up of an effusion in a suspect wet FIP case. To perform a Rivalta test, take 10 mls of water (must be at room temperature), add 2-3 drops of 8% acetic acid (ordinary clear/white vinegar) and carefully layer a drop of the effusion into it. If the effusion dissipates like a wisp of smoke in air the Rivalta test is negative and the cat is 97% not likely to have FIP. If, however, the effusion hangs from the surface in a globule, then slowly floats down like a jellyfish, the Rivalta test is positive. A positive Rivalta test means that the cat is 86% likely to have FIP (ie 5 of 6 cats with a positive Rivalta test do have FIP, so clearly other tests need to be performed to be more certain of the diagnosis). Dr Diane D. Addie is a veterinary virologist with two dreams: to eradicate feline infectious peritonitis (FIP) from the face of the earth, and to find a cure for feline chronic gingivostomatitis. You can read more about her ...