feline infectious peritonitis (fip)

This disease is thought to be caused by mutation of a virus that is quite widespread so sporadic cases of FIP are seen from time to time. The disease is seen most commonly in multi-cat households, affects young cats and is usually fatal. More than one form of the disease exist so the signs can be quite variable. They include progressive eye and neurological problems in the 'dry' form and fluid accumulation in the abdomen and chest in the 'wet' form, although both types can appear together.

SOURCE: cats.org.uk