FIP is caused by a feline coronavirus. Coronaviruses of various species exist in most types of animals and humans and usually cause acute respiratory or enteric disease. FIP is the cause of death of 1 in 100 to 1 in 300 cats in U.S. The incidence can be 5 or more times greater among young cats coming from catteries and shelters and is the major cause of abdominal fluid (ascites) and intraocular and neurologic inflammatory disease in cats under 3-5 years of age. FIP is virtually 100% fatal and there is no good prevention. The emotional toll of FIP is especially great, because it strikes suddenly weeks, months and even years after initial infection. Therefore, cat lovers usually experience this disease long after they have developed strong emotional bonds with their new pet.