Feline infectious peritonitis, or FIP, is a worldwide viral cat disease. Although not all cats infected with the virus will become ill or even develop FIP, once they do develop symptoms, there is a high chance that they will eventually succumb to it. What is the cause of FIP? FIP is a complicated disease, but is the result of a feline coronavirus infection. Similar to some human viruses, many cats – sometimes all of them in one household – will be infected, but only a few will ever have progressive symptoms and degeneration. FIP is thought to be a mutation of the coronavirus, and the effect it has seems to be also dependent on the cat’s own immune defense system. One bit of biological irony is that the FIP virus itself is not contagious, since it isn’t shed by the cat. However, the precursor form, coronavirus, is. What are the risks? FIP tends to affect younger cats (those three years old or less), but its symptoms and effects can happen at any age. This is probably because FIP tends to be more aggressive in cats that have weakened or immature immune systems. The corona virus itself is spread by direct contact, usually through the nose and mouth. The main source of transmission is cat feces, so shared litter boxes are a common cause for the spread of the virus within one household. Still, it is a maddening hit or miss situation, since some cats will become carriers, while others will develop FIP. Symptoms FIP tends to have two distinct subsets of symptoms, though it’s possible for some cats to share symptoms from both sets. Wet Form • Distended abdomen due to fluid build-up • Breathing difficulties • Long-term fever that does not respond to treatment • Loss of appetite and ensuing weight loss • Depression Dry Form • Long-term fever that does not respond to treatment • Loss of appetite and ensuing weight loss • Depression • Other symptoms related to organ failure, depending on which internal organs are affected; kidney, liver, pancreas, nervous systems, and eyes are usually affected Diagnosis Confirmation can actually be very difficult, with biopsies probably being the best way to check for it, in combination with microscopic tissue analysis, blood tests, and analysis of the fluid from the abdomen, if it is in the wet form. For the coronavirus, one can test for antibodies, but this will only serve as a filter before an infected cat is introduced to a local population – again, though a cat may have coronavirus, it may not lead to FIP unless the immune system is impaired or weakened. Treatment Unfortunately, there is no decisive treatment for FIP. Once the symptoms start, one can go through a set of supportive measures to prolong the cat’s health and quality of life, but in general, the wet form of FIP will have the cat succumb in days or weeks, with the dry form taking up to several months. Prevention Prevention is easy to say, but hard to do. Feline companions have to be prevented from being exposed to the coronavirus. Two of the most effective ways is to keep your feline companion indoors, and to make sure no cat with the coronavirus ever comes into the house. There is a vaccine, but its effectivity is controversial at best, as it should be given before the cat is infected.